This document summarizes Transcranial Direct Current Stimulation (tDCS). It discusses the history of tDCS, how it works, applications in therapeutic and enhancement contexts, physiological effects and basis, safety considerations, and the future of research. tDCS involves applying a weak electrical current to the brain via electrodes to modulate cortical excitability. It has therapeutic potential for conditions like depression, motor rehabilitation, and is being studied for cognitive enhancement. Research suggests its effects are mediated by changes in neuronal membrane potentials and synaptic plasticity.
Transcranial direct current stimulation Andri Andri
Transracial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that delivers low currents of electricity to modulate neuronal activity. It has been studied as a treatment for conditions such as depression, stroke rehabilitation and cognitive impairment. While generally safe with minor side effects like skin irritation and fatigue, more research is still needed on its efficacy and long term effects before it can be recommended in clinical practice. tDCS holds promise as a treatment to induce neuroplasticity but requires further evaluation in controlled trials.
This document provides an overview of a tDCS badge workshop. It discusses what tDCS is, common electrode placements and montages used for conditions like depression, addiction, and ADHD. Safety disclaimers are provided. The workshop demonstrates calibrating and using a DIY tDCS device, and provides resources for further learning. The presenters are independent biohacking enthusiasts who aim to objectively share their research while acknowledging limitations and risks of DIY use.
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that uses low direct current delivered through electrodes placed on the scalp to modulate cortical excitability. Several studies reviewed found that anodal tDCS over the affected motor cortex and cathodal tDCS over the unaffected motor cortex improved motor performance in stroke patients. Parameters like current dosage, electrode size and position, and stimulation duration need to be defined to induce different physiological effects. tDCS shows promise as a treatment for stroke rehabilitation and other neurological conditions by enhancing or inhibiting neural activity in targeted brain regions.
Brain Stimulation & Neuromodulation September 2016 - BH SummitJay Yeomans
Brain stimulation techniques like transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) show promise for treating neuropsychiatric conditions like depression. TMS uses magnetic fields to noninvasively stimulate areas of the brain and has been FDA approved for treating depression, while ECT uses electric currents to induce controlled seizures and is very effective for severe depression. Newer non-invasive techniques like transcranial direct current stimulation (tDCS) are also being studied for modulating brain activity. These neuromodulation approaches aim to alter brain circuits and neurotransmitter activity to improve mood and other symptoms.
Nerve conduction studies and electromyography are used to diagnose disorders of the peripheral nervous system including motor and sensory neurons, nerve roots, plexuses, peripheral nerves, neuromuscular junctions, and muscles. The document provides details on the anatomy and physiology relevant to nerve conduction studies and electromyography. It then describes the fundamentals and technical aspects of performing nerve conduction studies to evaluate motor, sensory, and mixed nerves. Common conduction study patterns are presented to characterize axonal loss, demyelination, myopathies, and neuromuscular junction disorders. Late responses including F-waves, H-reflexes, and axon reflexes are also summarized.
Evoked potentials are low amplitude electrical potentials recorded from the brain or peripheral nerves in response to sensory stimuli. They are used to evaluate the function of sensory and motor pathways. There are several types including sensory evoked potentials from visual, auditory and somatosensory stimulation as well as motor evoked potentials. Recording techniques involve signal averaging to detect the low amplitude signals. Evoked potentials provide objective measures for diagnosing various neurological disorders.
Trans cranial magnetic stimulation - Diagnostic & Therapeutic applicationNeurologyKota
Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses electromagnetic induction to stimulate neural tissue without causing pain. TMS can have acute effects like activating neural circuits or disrupting speech, as well as prolonged effects like changing synaptic strength and modulating cortical excitability. TMS has diagnostic applications like measuring motor thresholds and central motor conduction time to evaluate motor pathways, and therapeutic applications for treating depression, Parkinson's disease, neuropathic pain, and more. Common TMS protocols include single pulse, paired pulse, and repetitive TMS with low or high frequency stimulation. TMS is generally safe but can infrequently cause minor side effects like headaches.
Transcranial direct current stimulation Andri Andri
Transracial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that delivers low currents of electricity to modulate neuronal activity. It has been studied as a treatment for conditions such as depression, stroke rehabilitation and cognitive impairment. While generally safe with minor side effects like skin irritation and fatigue, more research is still needed on its efficacy and long term effects before it can be recommended in clinical practice. tDCS holds promise as a treatment to induce neuroplasticity but requires further evaluation in controlled trials.
This document provides an overview of a tDCS badge workshop. It discusses what tDCS is, common electrode placements and montages used for conditions like depression, addiction, and ADHD. Safety disclaimers are provided. The workshop demonstrates calibrating and using a DIY tDCS device, and provides resources for further learning. The presenters are independent biohacking enthusiasts who aim to objectively share their research while acknowledging limitations and risks of DIY use.
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that uses low direct current delivered through electrodes placed on the scalp to modulate cortical excitability. Several studies reviewed found that anodal tDCS over the affected motor cortex and cathodal tDCS over the unaffected motor cortex improved motor performance in stroke patients. Parameters like current dosage, electrode size and position, and stimulation duration need to be defined to induce different physiological effects. tDCS shows promise as a treatment for stroke rehabilitation and other neurological conditions by enhancing or inhibiting neural activity in targeted brain regions.
Brain Stimulation & Neuromodulation September 2016 - BH SummitJay Yeomans
Brain stimulation techniques like transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) show promise for treating neuropsychiatric conditions like depression. TMS uses magnetic fields to noninvasively stimulate areas of the brain and has been FDA approved for treating depression, while ECT uses electric currents to induce controlled seizures and is very effective for severe depression. Newer non-invasive techniques like transcranial direct current stimulation (tDCS) are also being studied for modulating brain activity. These neuromodulation approaches aim to alter brain circuits and neurotransmitter activity to improve mood and other symptoms.
Nerve conduction studies and electromyography are used to diagnose disorders of the peripheral nervous system including motor and sensory neurons, nerve roots, plexuses, peripheral nerves, neuromuscular junctions, and muscles. The document provides details on the anatomy and physiology relevant to nerve conduction studies and electromyography. It then describes the fundamentals and technical aspects of performing nerve conduction studies to evaluate motor, sensory, and mixed nerves. Common conduction study patterns are presented to characterize axonal loss, demyelination, myopathies, and neuromuscular junction disorders. Late responses including F-waves, H-reflexes, and axon reflexes are also summarized.
Evoked potentials are low amplitude electrical potentials recorded from the brain or peripheral nerves in response to sensory stimuli. They are used to evaluate the function of sensory and motor pathways. There are several types including sensory evoked potentials from visual, auditory and somatosensory stimulation as well as motor evoked potentials. Recording techniques involve signal averaging to detect the low amplitude signals. Evoked potentials provide objective measures for diagnosing various neurological disorders.
Trans cranial magnetic stimulation - Diagnostic & Therapeutic applicationNeurologyKota
Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses electromagnetic induction to stimulate neural tissue without causing pain. TMS can have acute effects like activating neural circuits or disrupting speech, as well as prolonged effects like changing synaptic strength and modulating cortical excitability. TMS has diagnostic applications like measuring motor thresholds and central motor conduction time to evaluate motor pathways, and therapeutic applications for treating depression, Parkinson's disease, neuropathic pain, and more. Common TMS protocols include single pulse, paired pulse, and repetitive TMS with low or high frequency stimulation. TMS is generally safe but can infrequently cause minor side effects like headaches.
Nerve conduction studies (NCS) involve stimulating peripheral nerves and recording electrical responses to evaluate the nerves' electrical properties. NCS can diagnose focal and generalized nerve disorders, differentiate between nerve and muscle disorders, and classify abnormalities as axonal or demyelinating. Sensory nerve action potentials and motor compound muscle action potentials are recorded. Analysis of latency, amplitude, duration and conduction velocity provides information about nerve damage localization and severity. Electromyography detects electrical activity in muscles and identifies normal, denervated, and reinnervating states. Together, NCS and EMG objectively assess peripheral nerve and muscle disorders.
Transcranial magnetic stimulation (TMS) is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain and has shown positive results in treating depression. Repetitive transcranial magnetic stimulation (rTMS) involves placing an electromagnet against the patient's head to deliver magnetic bursts and stimulate the brain region involved in mood control. rTMS has evolved as a tool for improving various neurological and psychiatric disorders beyond just depression.
Transcranial magnetic stimulation (TMS) is a noninvasive method to cause depolarization or hyperpolarization in the neurons of the brain.
This video explains the physics of this method and how it can be used in daily practice.
More about magnetic simulators: http://www.neurosoft.ru/eng/product/neuro-msd/index.aspx
The document discusses various newer neuromodulation methods for treating psychiatric disorders such as magnetic seizure therapy, transcranial alternating current stimulation, transcranial random noise stimulation, optogenetics, thermal stimulation, auricular stimulation, trigeminal nerve stimulation, transcranial ultrasound, and chemical stimulation. It provides details on the mechanisms of each method and reviews evidence from human and animal studies. Applications for several of these newer neuromodulation methods in clinical settings like depression, schizophrenia, cognitive enhancement, pain, and epilepsy are also mentioned.
The QEEG is a non-invasive brain imaging procedure that measures brain wave activity through electrodes placed on the scalp. Brain waves are recorded both at rest and during tasks to analyze characteristics like frequency, amplitude, and distribution. These characteristics are then compared to a normal database to evaluate metrics like relative power, asymmetry, coherence, and phase which provide information about brain performance and efficiency. The QEEG can be used to assess conditions like traumatic brain injury, learning disabilities, and neurological or psychological disorders.
This document provides an overview of different non-invasive brain stimulation techniques, including electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), and theta burst stimulation (TBS). It describes the history, mechanisms, applications, and side effects of each technique. ECT involves inducing seizures with electricity to treat conditions like depression. tDCS uses weak electrical currents to modulate cortical excitability. TMS uses electromagnetic induction to stimulate targeted brain regions without surgery. These non-invasive methods can modulate brain activity and connectivity to treat various neurological and psychiatric disorders.
Electroencephalography (eeg),electrical activity recorded via electrodes on the scalp,Neurophysiological Basis of EEG,Scalp EEG Recordings,Wearable EEG Devices,Recording EEG Signals,EEG Rhythms,
This document provides information on performing and interpreting nerve conduction studies. It discusses how peripheral nerves are stimulated electrically and the responses that are recorded, including compound motor action potentials, sensory nerve action potentials, and F-waves. It describes how to position electrodes and set stimulation parameters. Key aspects of the recorded waveforms like latency, amplitude, conduction velocity and abnormalities are defined. Common nerve conduction study techniques, interpretations, and limitations are also outlined.
This document provides information about nerve conduction studies (NCS). It discusses the basic components of a NCS including compound muscle action potentials, sensory nerve action potentials, F-waves, and H-reflexes. It describes the procedure, techniques, and applications of NCS in evaluating conditions like neuropathies, radiculopathies, and neuromuscular junction disorders. Limitations include NCS only assessing the largest nerve fibers and conditions proximal to the dorsal root ganglia potentially showing normal results.
This document discusses evoked potentials, which are electrical activities in the neural pathway generated in response to external stimuli. It focuses on three types of sensory evoked potentials: visual evoked potentials (VEP), somatosensory evoked potentials, and brainstem auditory evoked potentials (BEAP). VEP assess the visual pathway and look for abnormalities in P100 latency and amplitude. BEAP assess the auditory pathway by analyzing wave latencies and amplitudes, with abnormalities indicating lesions in the auditory nerve, brainstem, or cranial nerves. Evoked potentials are used to detect disturbances in the central nervous system.
Nerve conduction studies are used to evaluate the function of motor and sensory nerves. They involve stimulating nerves with controlled electrical pulses and recording the responses. For motor nerve conduction studies, the compound muscle action potential is recorded from muscles. Key measurements are latency, amplitude, and conduction velocity. For sensory nerve conduction studies, the sensory nerve action potential is recorded from sensory nerves. Common sites tested include the median, ulnar, and sural nerves. The results can help diagnose various peripheral nerve and neuromuscular disorders.
Electrodiagnosis can help diagnose Guillain-Barré syndrome (GBS) within the first week, when other tests may be normal. An absent H-reflex combined with abnormal F-waves and upper extremity sensory nerve action potentials, with normal sural nerve responses, suggests early GBS. From days 1-4, an absent H-reflex is most common abnormal finding. By days 5-7, 50-75% of patients show these characteristic electrodiagnostic features. Over time, motor nerve responses become more abnormal with low amplitudes, prolonged distal latencies, and slowed conduction velocities. Outcomes correlate with preserved motor nerve amplitudes—lower amplitudes indicate slower recovery.
Somatosensory evoked potentials (SEPs) measure electrical activity in the nervous system in response to stimulation of sensory nerves. SEPs of the median nerve and tibial nerve are commonly studied. Abnormalities can localize lesions along the sensory pathways. Prolonged latencies may indicate demyelination as in multiple sclerosis or transverse myelitis, while normal latencies with prolonged intervals suggest lesions of the spinal cord or brain. SEPs are useful for evaluating spinal cord and brain function and are often monitored during surgeries.
Pain is defined as an unpleasant sensory and emotional experience caused by actual or potential tissue damage. It is subjective and based on past experiences. Pain is transmitted through nociceptors and nerve fibers to the spinal cord and brain. It can be acute or chronic. Various factors like emotions, beliefs, and expectations can influence one's pain experience. The brain modulates pain transmission through descending pain pathways that release neurotransmitters like endorphins and serotonin.
This document provides an overview of electromyography (EMG) techniques and normal EMG findings. It describes how EMG is used to study electrical activity in muscles to aid in neurological examination. It explains the motor unit, action potential generation, different electrode types, equipment, procedures, and normal EMG findings like insertional activity, end plate noise and spikes, fibrillation and fasciculation potentials, and motor unit action potentials. Precautions for the procedure and factors that can influence EMG readings are also summarized.
The basal ganglia are brain nuclei that coordinate movement and cognitive functions. Deep brain stimulation (DBS) involves surgically implanting electrodes into the basal ganglia to deliver electrical stimulation for treating movement and neuropsychiatric disorders like Parkinson's disease. DBS was introduced in the 1990s and works by inhibiting or activating target areas in the basal ganglia to disrupt pathological oscillations. Common targets for stimulation include the subthalamic nucleus and globus pallidus. DBS improves motor symptoms in Parkinson's patients and allows for reductions in medication. Potential risks include infection, bleeding in the brain, and device-related complications.
Neuromodulation therapies like TMS and ECT allow targeted delivery of electrical or magnetic signals to specific areas of the nervous system to improve neural function. TMS uses magnetic pulses to induce currents in the brain non-invasively, while ECT induces seizures via electrodes. Both can have antidepressant effects by modifying neurotransmitter systems and inducing neuroplasticity. Ongoing research aims to better understand mechanisms of action, optimize dosing parameters, and expand indications to other psychiatric conditions.
Nerve conduction studies are tests that evaluate peripheral nerve function. They involve stimulating nerves with electrodes and recording the electrical responses of muscles or sensory nerves. Key aspects covered in the document include:
- Motor and sensory nerve conduction studies are used to measure nerve conduction velocities and amplitudes of compound muscle action potentials and sensory nerve action potentials.
- Various instruments like oscilloscopes, amplifiers, and electrodes are used along with stimulators to perform these tests.
- Factors like temperature, age, height, and physiological variations between nerve segments can influence nerve conduction study results. Interpretation of results requires considering these potential confounding factors.
1. Evoked potentials are electrical potentials recorded from the brain following presentation of a stimulus. There are several types including visual, auditory, and somatosensory evoked potentials.
2. Visual evoked potentials assess the visual pathway by recording electrical activity in the brain in response to visual stimuli. Patterns or flashes of light are used to stimulate the retina.
3. Auditory evoked potentials evaluate the auditory pathway by recording brain activity following auditory clicks or tones. This can help detect lesions in the auditory nerve or brainstem.
This document discusses fundamental concepts in direct current circuits including:
1) The 7 base units of the International System of Units (SI) including the mole and ampere
2) SI derived units which are combinations of base units used to measure non-basic quantities like mechanical, electrical, and magnetic units
3) Significant figures, which is a method of rounding measurements to a desired number of figures like 6,250,000 for electrons per second in a circuit.
Nerve conduction studies (NCS) involve stimulating peripheral nerves and recording electrical responses to evaluate the nerves' electrical properties. NCS can diagnose focal and generalized nerve disorders, differentiate between nerve and muscle disorders, and classify abnormalities as axonal or demyelinating. Sensory nerve action potentials and motor compound muscle action potentials are recorded. Analysis of latency, amplitude, duration and conduction velocity provides information about nerve damage localization and severity. Electromyography detects electrical activity in muscles and identifies normal, denervated, and reinnervating states. Together, NCS and EMG objectively assess peripheral nerve and muscle disorders.
Transcranial magnetic stimulation (TMS) is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain and has shown positive results in treating depression. Repetitive transcranial magnetic stimulation (rTMS) involves placing an electromagnet against the patient's head to deliver magnetic bursts and stimulate the brain region involved in mood control. rTMS has evolved as a tool for improving various neurological and psychiatric disorders beyond just depression.
Transcranial magnetic stimulation (TMS) is a noninvasive method to cause depolarization or hyperpolarization in the neurons of the brain.
This video explains the physics of this method and how it can be used in daily practice.
More about magnetic simulators: http://www.neurosoft.ru/eng/product/neuro-msd/index.aspx
The document discusses various newer neuromodulation methods for treating psychiatric disorders such as magnetic seizure therapy, transcranial alternating current stimulation, transcranial random noise stimulation, optogenetics, thermal stimulation, auricular stimulation, trigeminal nerve stimulation, transcranial ultrasound, and chemical stimulation. It provides details on the mechanisms of each method and reviews evidence from human and animal studies. Applications for several of these newer neuromodulation methods in clinical settings like depression, schizophrenia, cognitive enhancement, pain, and epilepsy are also mentioned.
The QEEG is a non-invasive brain imaging procedure that measures brain wave activity through electrodes placed on the scalp. Brain waves are recorded both at rest and during tasks to analyze characteristics like frequency, amplitude, and distribution. These characteristics are then compared to a normal database to evaluate metrics like relative power, asymmetry, coherence, and phase which provide information about brain performance and efficiency. The QEEG can be used to assess conditions like traumatic brain injury, learning disabilities, and neurological or psychological disorders.
This document provides an overview of different non-invasive brain stimulation techniques, including electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), and theta burst stimulation (TBS). It describes the history, mechanisms, applications, and side effects of each technique. ECT involves inducing seizures with electricity to treat conditions like depression. tDCS uses weak electrical currents to modulate cortical excitability. TMS uses electromagnetic induction to stimulate targeted brain regions without surgery. These non-invasive methods can modulate brain activity and connectivity to treat various neurological and psychiatric disorders.
Electroencephalography (eeg),electrical activity recorded via electrodes on the scalp,Neurophysiological Basis of EEG,Scalp EEG Recordings,Wearable EEG Devices,Recording EEG Signals,EEG Rhythms,
This document provides information on performing and interpreting nerve conduction studies. It discusses how peripheral nerves are stimulated electrically and the responses that are recorded, including compound motor action potentials, sensory nerve action potentials, and F-waves. It describes how to position electrodes and set stimulation parameters. Key aspects of the recorded waveforms like latency, amplitude, conduction velocity and abnormalities are defined. Common nerve conduction study techniques, interpretations, and limitations are also outlined.
This document provides information about nerve conduction studies (NCS). It discusses the basic components of a NCS including compound muscle action potentials, sensory nerve action potentials, F-waves, and H-reflexes. It describes the procedure, techniques, and applications of NCS in evaluating conditions like neuropathies, radiculopathies, and neuromuscular junction disorders. Limitations include NCS only assessing the largest nerve fibers and conditions proximal to the dorsal root ganglia potentially showing normal results.
This document discusses evoked potentials, which are electrical activities in the neural pathway generated in response to external stimuli. It focuses on three types of sensory evoked potentials: visual evoked potentials (VEP), somatosensory evoked potentials, and brainstem auditory evoked potentials (BEAP). VEP assess the visual pathway and look for abnormalities in P100 latency and amplitude. BEAP assess the auditory pathway by analyzing wave latencies and amplitudes, with abnormalities indicating lesions in the auditory nerve, brainstem, or cranial nerves. Evoked potentials are used to detect disturbances in the central nervous system.
Nerve conduction studies are used to evaluate the function of motor and sensory nerves. They involve stimulating nerves with controlled electrical pulses and recording the responses. For motor nerve conduction studies, the compound muscle action potential is recorded from muscles. Key measurements are latency, amplitude, and conduction velocity. For sensory nerve conduction studies, the sensory nerve action potential is recorded from sensory nerves. Common sites tested include the median, ulnar, and sural nerves. The results can help diagnose various peripheral nerve and neuromuscular disorders.
Electrodiagnosis can help diagnose Guillain-Barré syndrome (GBS) within the first week, when other tests may be normal. An absent H-reflex combined with abnormal F-waves and upper extremity sensory nerve action potentials, with normal sural nerve responses, suggests early GBS. From days 1-4, an absent H-reflex is most common abnormal finding. By days 5-7, 50-75% of patients show these characteristic electrodiagnostic features. Over time, motor nerve responses become more abnormal with low amplitudes, prolonged distal latencies, and slowed conduction velocities. Outcomes correlate with preserved motor nerve amplitudes—lower amplitudes indicate slower recovery.
Somatosensory evoked potentials (SEPs) measure electrical activity in the nervous system in response to stimulation of sensory nerves. SEPs of the median nerve and tibial nerve are commonly studied. Abnormalities can localize lesions along the sensory pathways. Prolonged latencies may indicate demyelination as in multiple sclerosis or transverse myelitis, while normal latencies with prolonged intervals suggest lesions of the spinal cord or brain. SEPs are useful for evaluating spinal cord and brain function and are often monitored during surgeries.
Pain is defined as an unpleasant sensory and emotional experience caused by actual or potential tissue damage. It is subjective and based on past experiences. Pain is transmitted through nociceptors and nerve fibers to the spinal cord and brain. It can be acute or chronic. Various factors like emotions, beliefs, and expectations can influence one's pain experience. The brain modulates pain transmission through descending pain pathways that release neurotransmitters like endorphins and serotonin.
This document provides an overview of electromyography (EMG) techniques and normal EMG findings. It describes how EMG is used to study electrical activity in muscles to aid in neurological examination. It explains the motor unit, action potential generation, different electrode types, equipment, procedures, and normal EMG findings like insertional activity, end plate noise and spikes, fibrillation and fasciculation potentials, and motor unit action potentials. Precautions for the procedure and factors that can influence EMG readings are also summarized.
The basal ganglia are brain nuclei that coordinate movement and cognitive functions. Deep brain stimulation (DBS) involves surgically implanting electrodes into the basal ganglia to deliver electrical stimulation for treating movement and neuropsychiatric disorders like Parkinson's disease. DBS was introduced in the 1990s and works by inhibiting or activating target areas in the basal ganglia to disrupt pathological oscillations. Common targets for stimulation include the subthalamic nucleus and globus pallidus. DBS improves motor symptoms in Parkinson's patients and allows for reductions in medication. Potential risks include infection, bleeding in the brain, and device-related complications.
Neuromodulation therapies like TMS and ECT allow targeted delivery of electrical or magnetic signals to specific areas of the nervous system to improve neural function. TMS uses magnetic pulses to induce currents in the brain non-invasively, while ECT induces seizures via electrodes. Both can have antidepressant effects by modifying neurotransmitter systems and inducing neuroplasticity. Ongoing research aims to better understand mechanisms of action, optimize dosing parameters, and expand indications to other psychiatric conditions.
Nerve conduction studies are tests that evaluate peripheral nerve function. They involve stimulating nerves with electrodes and recording the electrical responses of muscles or sensory nerves. Key aspects covered in the document include:
- Motor and sensory nerve conduction studies are used to measure nerve conduction velocities and amplitudes of compound muscle action potentials and sensory nerve action potentials.
- Various instruments like oscilloscopes, amplifiers, and electrodes are used along with stimulators to perform these tests.
- Factors like temperature, age, height, and physiological variations between nerve segments can influence nerve conduction study results. Interpretation of results requires considering these potential confounding factors.
1. Evoked potentials are electrical potentials recorded from the brain following presentation of a stimulus. There are several types including visual, auditory, and somatosensory evoked potentials.
2. Visual evoked potentials assess the visual pathway by recording electrical activity in the brain in response to visual stimuli. Patterns or flashes of light are used to stimulate the retina.
3. Auditory evoked potentials evaluate the auditory pathway by recording brain activity following auditory clicks or tones. This can help detect lesions in the auditory nerve or brainstem.
This document discusses fundamental concepts in direct current circuits including:
1) The 7 base units of the International System of Units (SI) including the mole and ampere
2) SI derived units which are combinations of base units used to measure non-basic quantities like mechanical, electrical, and magnetic units
3) Significant figures, which is a method of rounding measurements to a desired number of figures like 6,250,000 for electrons per second in a circuit.
This document describes the design of an integrated EEG and tDCS device. It aims to provide simultaneous EEG recording and tDCS stimulation at a lower cost than existing research devices. The device uses an Arduino, EEG amplification circuit, and connects to a commercial tDCS device. Validation testing showed the EEG signals matched those from a commercial device. Future work includes addressing noise issues and further development by Dr. Amthor's lab. The goal is to enable lower-cost neuroscience research combining EEG and tDCS.
Cosmo-not: a brief look at methods of analysis in functional MRI and in diffu...CosmoAIMS Bassett
The document provides an overview of functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) analysis methods including Granger causality, principal component analysis (PCA), and independent component analysis (ICA). It describes how fMRI measures brain activity indirectly through the blood oxygenation level dependent (BOLD) signal and how this can be used to identify functional brain networks. It also briefly discusses DTI for analyzing structural brain connections and resting state fMRI for studying functional networks without an explicit task.
The document discusses the fundamentals and work mechanism of magnetic resonance imaging (MRI). It introduces MRI as a medical instrument used to scan and image the inside of the body. The author's PhD focus and the increased demand for MRI exams are cited as reasons for choosing this topic. The aim is to familiarize the reader with the MRI machine and what happens inside during an exam by explaining its main parts, work mechanism, image processing, advantages, disadvantages, and predictions for future development.
There are two main types of MRI sequences: spin echo (SE) and gradient echo (GE). SE produces better image quality but has longer scan times, while GE has shorter scan times. Key MRI parameters are repetition time (TR) and echo time (TE). Different MRI weightings (T1, T2, PD, FLAIR) provide contrast between tissues. Advanced MRI techniques like DWI, PWI, and MRS provide additional clinical information on diffusion, perfusion, and metabolism. Functional MRI (fMRI) uses the BOLD contrast to non-invasively map functional brain activity with good spatial and temporal resolution. MRI and its variants are useful clinical tools for diagnosis, treatment planning, and studying brain
This document discusses the use of functional MRI (fMRI) in preoperative planning for brain tumor patients. fMRI can help assess the relationship between functionally eloquent brain regions and tumor location to minimize postoperative deficits. It describes different tasks used in fMRI like motor and language tasks. Validation studies show high sensitivity and specificity for motor mapping but more variable results for language mapping. The document also discusses limitations of fMRI like spatial uncertainty and tumor effects on BOLD signal. Overall, fMRI provides useful information to guide surgery when used appropriately with an understanding of its limitations.
The document provides an introduction to functional magnetic resonance imaging (fMRI). It discusses how fMRI works by detecting changes in blood oxygenation, which serves as an indirect measure of neural activity. The basics of MRI are also reviewed, including how MRI uses strong magnetic fields and radio waves to generate images based on magnetic properties of tissue. Example fMRI studies measuring brain activity in response to visual stimuli are presented.
Marom Bikson speaks at the BrainSTIM2015 - Targeting transcranial Electrical Stimulation (tES) using EEG. Includes how to use EEG to inform transcranial Direct Current Stimulation (tDCS) montages. And critical pitfalls in concurrent recording. Stay tuned for our upcoming paper on reciprocity.
The complete video can be found here: https://www.youtube.com/watch?v=yYmDQB7qSCE
The first publication on the topic can be found here http://neuralengr.com/wp-content/uploads/2016/05/2016-Cancelli-A-simple-method.pdf
Related technology can be found here http://soterixmedical.com/research/monitoring/eeg
Transcranial Brain Stimulation: Science and EthicsJames David Saul
This document discusses the promise and potential risks of noninvasive brain stimulation techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). It notes that these techniques have shown promise in transiently improving cognition in domains like language, learning, attention, and problem-solving. They have also shown potential for mood enhancement and manipulating social cognition. However, the document also discusses safety concerns, issues of character and justice, and questions around autonomy that arise from the ability to manipulate human cognition and behavior without consent through these techniques.
FMRI is a functional neuroimaging technique that uses MRI technology to measure brain activity through changes in blood flow and oxygen use. When an area of the brain is in use, blood flow to that region increases. FMRI relies on this coupling of cerebral blood flow and neuronal activation, using the BOLD contrast method to observe different active areas of the brain. A neuron is an electrically excitable cell that processes and transmits information through electrochemical signals.
Magnetic resonance imaging (MRI) uses strong magnets and radio waves to produce detailed images of the inside of the body without using ionizing radiation. An MRI machine contains a powerful magnet to align hydrogen atoms in the body. Radio waves are then used to excite the atoms, which emit signals as they relax. These signals are detected by antennas and used by a computer to generate 2D or 3D images of tissues and organs. MRI provides excellent soft tissue contrast and is useful for imaging the brain, muscles, joints, and other internal organs. While it has advantages over CT in avoiding radiation, MRI scans can be costly and some patients may find the enclosed scanner space claustrophobic.
Functional magnetic resonance imaging (fMRI) indirectly measures brain activity by detecting changes in blood flow and oxygenation. It uses the difference in magnetic properties between oxygenated and deoxygenated hemoglobin, known as the blood oxygen level dependent (BOLD) signal. The BOLD signal is slow and noisy, peaks around 6 seconds after stimulation, and involves subtracting conditions to identify statistically significant activity changes. fMRI data is overlaid on high-resolution structural scans and analyzed using specialized maps of visual and other functional areas.
This document outlines an MRI brain protocol. It begins with an introduction to MRI brain imaging and its advantages over CT, such as lack of radiation exposure and greater soft tissue contrast. Common indications for MRI brain are then listed. The document describes patient preparation, contrast usage, coil positioning, imaging sequences including T1, T2, FLAIR, DWI, and advanced techniques like MRS and fMRI. Specific protocols are provided for conditions like MS, trauma, pituitary imaging, and CSF flow studies.
One of lectures presented in our Port said fifth neonatology conference, 23-24 October 2014 by Prof Mohamed El Sawy, Prof in Pediatric department , faculty of medicine, Ain Shams university
The parietal lobe is located at the top of the brain and is involved in processing somatosensory information, spatial awareness, and language comprehension. It contains the primary somatosensory cortex and association areas important for functions like tactile perception, discrimination, localization, and stereognosis. Injuries or lesions to different areas of the parietal lobe can cause syndromes like Gerstmann's syndrome involving acalculia, finger agnosia, and right-left disorientation if the angular gyrus is affected. The supramarginal gyrus is involved in tasks like praxis, repetition, and constructional abilities.
This slide will provide a tutorial for preprocessing of fMRI data. The step-by-step process will be provided.
visit my website for more information:
http:/skyeong.net
The parietal lobe is located at the top of the brain and is responsible for processing sensory information and integrating it with motor commands. It has clear boundaries defined by sulci and gyri. The parietal lobe can be divided into anterior and posterior zones, with the anterior zone processing somatic sensations and the posterior zone integrating visual and somatosensory information for movement. The parietal lobe plays an important role in functions like processing tactile information, visual control of movement, and spatial awareness.
A novel implantable dual microelectrode for monitoring/predicting post trauma...dharmakarma
Here, we describe a novel dual microelectrode concept based on brain oxygenation that can be used to predict seizures caused due to traumatic brain injury. Since brain oxygenation occurs slightly prior to chaotic neural firing, it can be used to predict in advance the occurrence of a seizure.
Neuroprime is a transcranial direct current stimulation (tDCS) device that sends a small electrical current into the brain via electrodes placed on the scalp. tDCS alters brain function and has shown promise in treating various conditions such as depression, anxiety, stroke recovery, and cognitive issues. For depression specifically, clinical trials have found tDCS reduces symptoms and is comparable to antidepressants, with effects lasting over a month. The device is considered safe and works by making neurons in targeted brain areas more or less sensitive to stimulation over subsequent sessions.
Electrophysiological imaging for advanced pharmacological screening3Brain AG
We at 3Brain are committed to advancing scientific research and boosting drug discovery. Like our technology, our product lines are always evolving to accommodate high-resolution recording of in vitro cultures. Discover our HD-MEA technology and soon-to-be-released devices and see how they are furthering research in brain diseases, drug discovery, retinal organoids, etc..
For more information, visit our website at https://www.3brain.com
Nicotinergic impact on focal and non focal neuroplasticity induced by non-inv...merzak emerzak
This study investigated the effects of nicotine on neuroplasticity induced by non-invasive brain stimulation techniques. 48 healthy non-smokers received either nicotine or placebo patches combined with transcranial direct current stimulation (tDCS) or paired associative stimulation (PAS) applied to the motor cortex. Motor evoked potentials were measured as an indicator of corticospinal excitability. Nicotine abolished or reduced inhibitory neuroplasticity induced by both tDCS and PAS, but only slightly prolonged facilitatory plasticity induced by PAS. Thus, nicotine influences plasticity differently than global cholinergic enhancement, demonstrating discernible effects of activating nicotinic receptors.
Transcranial direct current stimulation as a treatment option in CSWS-prelimi...Edina Timea Varga
Cathodal transcranial direct current stimulation was tested as a potential treatment for continuous spikes and waves during slow wave sleep in children. The study aimed to detect the effect of cathodal tDCS on epileptiform EEG discharges in three patients. Cathodal tDCS was applied at 1 mA for 20 minutes over the epileptic focus. While no effect was seen in two patients, spike wave activity disappeared after sham stimulation in one patient. Larger studies are still needed to reliably determine the efficacy of tDCS for treating continuous spikes and waves during slow wave sleep.
RGN investor presentation January 2015Alex Deleuse
Rio Grande Neurosciences (RGN) is developing non-invasive brain stimulation technologies to treat neurological conditions without drugs. Their lead technology, targeted Pulsed ElectroMagnetic Field (tPEMF) therapy, aims to reduce neuroinflammation and enhance blood flow in traumatic brain injury (TBI). RGN plans clinical studies of tPEMF for concussions and is researching its potential to treat neurodegeneration. They intend to license other non-invasive neurostimulation technologies and consolidate the fragmented non-invasive brain stimulation market.
The document summarizes research on neural engineering related to cochlear implants and intracortical microelectrodes. It discusses:
1) Cochlear implant research involving developing a method to fit implants using stapedius electromyography recordings in rats.
2) Chronic neural interfacing research using intracortical microelectrodes to record brain activity, the challenges of long-term recordings due to tissue encapsulation, and methods explored to address this like enzyme-aided electrode insertion.
3) The quantification of recording performance over time and correlations with electrode impedance.
Clinical Results and Mechanisms of MAGCELL®-Therapy in Chemotherapy-Induced P...Mary Fickling
Electrode-free electrotherapy also known as MAGCELL®-therapy, arrived in the UK and Ireland in 2017 via exclusive distributors PhysioPod® UK Limited. This article, explains the clinical results and mechanism of MAGCELL® MICROCIRC in CIPN with scientific references.
MAGCELL® MICROCIRC can positively influence symptoms of neurotoxicities like sensory ataxia, neuropathy and neuropathic pain symptoms (especially CIPN I-IV) on hands and feet as a result of chemotherapy. Moreover a significant increase in nerve conductivity speed (ulnar nerve) was achieved by the treatment. Sufferers are now able to apply this effective treatment at home via the personal unit, due to repeatable short-treatment periods, no side effects and even through textile (including shoes).
1) MECTA is an innovator in neuromodulation technologies and has introduced new electroconvulsive therapy (ECT) parameter sets that aim to improve efficacy while reducing cognitive side effects.
2) Their ultrabrief ECT parameters use a very short 0.3 ms pulse width, allowing treatments to be given at lower dosages with research showing greatly reduced cognitive effects compared to standard brief pulse ECT.
3) Their new optimized and full spectrum dosing parameter sets continue to utilize the 0.3 ms ultrabrief pulse width across different current ranges and have been shown to be as effective as bilateral ECT with fewer cognitive impacts.
This document discusses new technologies for treating depression, focusing on transcranial magnetic stimulation (TMS), vagus nerve stimulation (VNS), deep brain stimulation (DBS), and magnetic seizure therapy (MST). It examines what each technology is, how effective and established its use is, possible future directions, and what we have learned from its use. Key areas targeted for TMS, DBS and MST are identified as being the prefrontal cortex, subgenual cingulate cortex, and hippocampus respectively. The document evaluates the mechanisms, side effects, and changes in brain activity associated with each method.
Martin Smith
The management of severe traumatic brain injury (TBI) has undergone extensive revision following evidence that longstanding and established practices are not as efficacious or innocuous as previously believed. Very few specific interventions have been shown to improve outcome in large randomized controlled trials and, with the possible exception of avoidance of hypotension and hypoxaemia, most are based on observational studies or analysis of physiology and pathophysiology. Further, the substantial temporal and regional pathophysiological heterogeneity after TBI means that some interventions may be ineffective, unnecessary or even harmful in certain patients at certain times.
Improved understanding of pathophysiology and advances in neuromonitoring and imaging techniques have led to the introduction of more effective and individualised treatment strategies that have translated into improved outcomes for patients. In particular, the sole goal of identifying and treating intracranial hypertension has been superseded by a focus on the prevention of secondary brain insults using a systematic, stepwise approach to maintenance of adequate cerebral perfusion and oxygenation. As well as being used to guide treatment interventions, multimodal neuromonitoring also gives clinicians confidence to withhold potentially dangerous therapy in those with no evidence of brain ischemia/hypoxia or metabolic disturbance.
The days of blind adherence to generic physiological targets in the management of severe TBI have been replaced by an individualised approach to optimisation of physiology which has translated into improved outcomes for patients.
Mark Wilson
The New England Journal of Medicine has published a number of articles recently that demonstrate no benefit from classic neurotrauma interventions (ICP monitoring, cooling, decompression). This is because factors such as ICP and CPP are associated with bad outcome by association rather than causation. This debate will demonstrate that critical care just complicates things and it is high time for the randomised trial between the very best Neurocritical care and NOB therapy (Naso-pharyngeal, Oxygen and a Blanket).
This study investigated the effects of transcranial direct current stimulation (tDCS) on electroencephalogram (EEG) activity. 10 participants underwent EEG recording before, during, and after tDCS applied to the left dorsolateral prefrontal cortex. Analysis found that beta frequency power in the EEG significantly increased during stimulation and remained elevated after. This suggests tDCS may enhance cognitive functioning by increasing beta frequency activity in the brain. No significant changes were observed in other frequency bands. This is the first study to systematically analyze pre-, during-, and post-stimulation EEG data concurrent with tDCS.
Searching for the optimal tdcs target for motor rehabilitationIkramInf
1) tDCS is a noninvasive brain stimulation technique that can modulate cortical excitability through electrodes placed on the scalp. Different electrode placements and polarities have varying effects.
2) The study discusses evidence for four tDCS montages to promote motor rehabilitation: anodal ipsilateral/cathodal bilateral stimulation, central and peripheral stimulation combination, prefrontal stimulation, and cerebellar stimulation.
3) Preliminary findings show benefits for motor recovery, but optimal parameters are still unclear as studies use heterogeneous methods. The ideal montage should be tailored to each patient's characteristics and safety based on evidence quality.
In Feb 2022, Dr. Cassano presented this NYU-MGH study at LifeStance Health. The presentation covers in-vitro and pre-clinical data in support of the use of transcranial PBM for Alzheimer’s disease (AD). The most recent clinical data on PBM for AD were also reviewed. The NYU-MGH study was described: a large randomized, double-blind clinical trial (n=125) sponsored by NIH/NIA and by the Alzheimer’s Association.
Lessons from the TTM trial and planning for the nexstscanFOAM
1) Detailed neurological examinations and blinded prognostication were conducted in the TTM trials to minimize bias in outcomes.
2) Follow-up assessments at 6 months in TTM1 found cognitive impairment, depression, and reduced quality of life in about one third of patients despite similar mortality between groups.
3) Extended cognitive testing in TTM1 at 6 months revealed memory, executive function, and processing speed impairments in about half of patients, more than in risk-factor matched controls, showing long-term cognitive consequences after cardiac arrest.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Intro to Transcranial Direct Curent Stimulation (tDCS)
1. Transcranial Direct Current
Stimulation (tDCS)
Daniel C. Stevenson
daniel.cortez.stevenson@gmail.com
https://www.linkedin.com/in/daniel-c-stevenson/
Presented in Fall, 2015
1
2. Agenda
1. History, tDCS vs. TMS, applications, & efficacy
2. Physiological effects of tDCS
3. Physiological basis of tDCS
4. Safety, DIY, and the FDA
5. Future Directions
2
11. Parkinson’s: Dose-dependent effects
11
Boggio et al. (2006). Journal of Neurological Sciences,
249(1): 31-38.
N=18
Duration=20min
3-Back Working Memory Test during last
5min of stimulation
12. Depression: Combination
Therapy
12Brunoni et al. (2013). JAMA Psychiatry 70(4): 383-91
Dorsolateral Prefrontal Cortex (DLPFC)
Located at F3,F4
N=120
Strength=2mA
Duration=30min
Frequency=1/day for 10 days; 4wks; 6wks
13. Enhancement Application
• Motor learning
• Language learning
• Visual perception
• Working memory
• Attention
• Problem-solving
• Moral judgment
13
14. Target Detection: Task x tDCS effects
14
Clark et al. (2010). NeuroImage, 59(1): 117-128.
RIF=right inferior frontal
Anodal Stimulation
Duration=30min
15. 15
Target Detection: Task x tDCS effects
Clark et al. (2010). NeuroImage, 59(1): 117-128.
N2.0mA=26
N0.1mA=36
17. Is there really an effect?
• Horvath, J. C., Forte, J. D., & Carter, O. (2015). Quantitative
review finds no evidence of cognitive effects in healthy
populations from single-session transcranial direct current
stimulation (tDCS). Brain Stimulation, 8(3): 535-550.
• Price, A. R., & Hamilton, R. H. (2015). A re-evaluation of the
cognitive effects from single-session transcranial direct
current stimulation. Brain Stimulation 8(3): 663-665.
• Horvath, J. C. (2015). New quantitative analysis following
Price & Hamilton’s critique do not change original findings
of Horvath et al. Brain Stimulation 8(3): 665-666.
• Nitsche, M. A., Bikson, M., & Bestmann, S. (2015). On the
use of meta-analysis in neuromodulatory non-invasive brain
stimulation. Brain Stimulation 8(3): 666-667.
17
19. Methodology
Abductor digiti minimi muscle
of the hand (ADM)
Tendon
Belly
Surface EMG Recordings of TMS
induced Motor Evoked Potentials
(MEPs)
Ag-AgCl
electrodes are
placed in a
“belly-tendon
montage”
19
21. Pyrimidal Tract Neurons:
Corticospinal-Upper motor neurons originating
in layer 5 of the cortex terminate in spinal cord and
innervate lower motor neuron
Corticobulbular-terminate in brainstem
21
32. Current modifies elicited neuron firing
(in rats)
32
Anodal Stimulation Cathodal Stimulation
Bindman et al. (1964) J Physiol 172: 369-382
*b,d are control traces
33. Current modifies tonic neuron firing
(in rats)
33
Control
Cathodal
Anodal
Bindman et al. (1964) J Physiol 172: 369-382
34. Na+ Voltage Gated
Channels
Nitsche et al. (2003). J Physiology 533.1: 293-301
CBZ = carbamazepine (600mg);
Na+ channel blocker
* Indicates significant difference
from the respective PLC/Drug
condition
NI=12
N0=12
NI=10
N0=10
No ∆
34
During tDCS
35. Conclusions: During tDCS Effects
• Resting membrane potential is modulated by
the electrical current
• Anodal effects are abolished by blocking Na+
channels
• These effects are necessary for longer-term
effects to occur
35
36. Long-term potentiation/depression
(LTP/LTD)
• Modulation of synaptic strength
• Occurs within the horizontal connections of
the primary motor cortex (during motor
learning and rehabilitation)
– Glutamatergic interneurons
• NMDA receptors
• AMPA receptors
36
37. Early LTP is Ca2+ dependent
37
Lynch, M. A. (2004). Long-term potentiation and memory.
Physiological Reviews 84(1): 87-136.
41. Conclusions: NMDAR/Ca2+
• NMDAR-mediated LTP is integral to long-term
tDCS effect
– NMDA antagonism eliminates both cathodal and
anodal long-term effects
– NMDA agonism enhances anodal tDCS
• Ca2+ channels mediate short-term tDCS effect
• Ca2+ channels necessary for longer-term
effects
– NMDAR interaction
41
42. Conclusions: Physiological Basis
1. Short-term effects are mediated by sub-
threshold alterations in neuron resting
membrane potential
2. Long-term effects are mediated by LTP
involving NMDA receptors
42
43. Safety: Adverse Effects
• 63% of studies report 1 mild ‘adverse effect’
– Itching, tingling, headache, burning sensation,
discomfort
• However:
– Active tDCS Rate = Sham Rate
– Except:
• Skin reddening (Tx w/ Ketoprofen)
43
Fregni et al. (2014). Clinical Research and Regulatory Affairs, [Early
Online]: 1-14.
44. Safety: Serious Adverse Effects
• Review: No “serious adverse events” since
1998 in >10,000 subjects
• 1964 study: “respiratory and motor paralysis”
– Bifrontal anodal electrodes with leg cathode
– 10x intended current strength (likely ~3mA)
– DIY-tDCS concerns
44
Fregni et al. (2014). Clinical Research and Regulatory Affairs, [Early
Online]: 1-14.
Lippold O. C. J., & Redfearn, J. W. T. (1964). Mental changes resulting
from the passage of small direct currents through the human brain.
110(469): 768-772
45. Safety: Physiological Evidence
• No pathological changes in:
– Serum enolase (marker of neuronal damage)
– HRV
– EEG
• 100x the charge density used in humans is
required to cause brain damage in rats
– Discomfort in humans starts at 2-3x
45
Fregni et al. (2014). Clinical Research and Regulatory Affairs, [Early
Online]: 1-14.
47. Safety: Standard Parameters
• Current strength <2.5mA
• Duration <60min
• ≤2 sessions per day
• This does not imply going beyond these
parameters is not safe!
47
Fregni et al. (2014). Clinical Research and Regulatory Affairs, [Early
Online]: 1-14.
48. Safety: Unknowns
• Long-term usage
• Need for more studies on safety
48
Fregni et al. (2014). Clinical Research and Regulatory Affairs, [Early
Online]: 1-14.
49. FDA Regulations
• “Medical device”
– Most stimulators are Class II
• “Investigational Device Exception” approval
– “non-significant risk” exception “expedited IDE”
– NSR overwhelmingly applied
• “Minimal Risk”
• Not cleared for any medical indication
49
50. tDCS Research is Accelerating
• 2008: Review of 122 tDCS studies since 1998a
– physiological effects of tDCS
– pharmacological modulation of tDCS
– establishing application protocols
• 2008-2010: ~100 new tDCS studiesb
– enhancing the efficacy of protocols
– defining safety parameters
– broadening the range of application
50
a Nitsche et al. (2008). Brain Stimulation, 1: 206-233.
b Nitsche, M. A., & Paulus, W. (2011). Restorative Neurology and Neuroscience, 29:463-492.
51. tDCS Research is Accelerating
51
0
100
200
300
400
500
#ofPublications
Year
PubMed publications on the subject
"transcranial direct current stimulation" since 1998
http://dan.corlan.net/medline-trend.html
52. Future Research Should Explore…
• effects of tDCS on cortical areas outside of M1
– neurotransmitters, receptors, neurons, and
networks are heterogeneous
• interaction of of [Stimulation x Task]
• timing and duration of stimulation (before,
during or after a task)
• multi-electrode stimulation of functional
networks
52
Shin, Y.-I., Foerster, A., & Nitsche, M. A. (2015).
Neuropsychologia, 69: 154-175
53. Overview: tDCS…
• is an exciting and novel electrical stimulation
device with a long history
• has a wide variety of applications
• modifies the resting membrane potential of
cells, and can induce lasting changes in
neuronal plasticity
• is of minimal risk, yet still awaits FDA approval
• tDCS research is booming, but has a long way
to go
53
Scribonius Largus
Sudden, transient stupor with pain relief
Relief due to numbness, torpor, and narcotic effect from electric fish
Alos Pliny the Elder and Greek physician Claudius Glaen (131-401 AD)
Ibn-Sidah
Muslin physician
Placed on frontal bone
Alessandro Volta
Electrical stimuli of varying du7ration can evoke different physiological effects
Discusions with Galvani started the electrical century
Many different applications of electricity (including medicine)
DC current = Galvanic Current = Voltaic Current
Giovanni Aldini (Galvani’s nephew)
Facial muscle contractions in guillotined cadavers
On himself: induced insomnia for a few days and ‘unpleasant sensation’
Augistin and Grapengiesser
DC currents as stimulating or sedative treatment
Bishoff
Successful Tx in a case of depression
1938: Cerletti treats 1st patient with ECT
Priori 2003 Clinical Neurophysiology
Kuo, Paulus, & Nitsche (2014) NeuroImage
Fregni et al, Clinical Research and Regulatory Affairs (2014)
Tinnitus
Anodal tDCS reduces intensisty of symptoms
Stroke
Daily sessions of tDCS improve upper limb function, increase activities of daily living (ADLs) scores
Various Montages, w/ or w/out Physical Therapy improve motor function in mild to moderate stoke patients
Anodal tDCS over perilesional areas improves language function, persists over time when coupled with language training
Stability of improvement over clinically significant intervals remains to be assessed.
Alzheimer’s
May improve memory performance
rtDCS creates effects lasting >4 weeks
Addiction
Effective in reducing cravings for food, smoking, concaine and alcohol.
As effective as rTMS in reducing cravings in substant dependent people and cravings for palatable food
DLPFC
Post-Polio Syndrome
Anodal tDCS over pre-motor areas improves sleep and fatigue symptoms
Brunoni et al. (2013). The Sertraline vs Electrical Current Therapy for Treating Depression Clinical StudyResults From a Factorial, Randomized, Controlled Trial. JAMA Psychiatry 70(4): 383-391
Nitsche, M. A., & Paulus, W. (2011). Transcranial direct current stimulation – update 2011. Restorative Neurology and Neuroscience, 29:463-492.
Clark et al. (2010). TDCS guided using fMRI significantly accelerates learning to identify concealed objects. NeuroImage, 59(1): 117-128.
Subjects with 2.0mA stimulation were also better than sham at both post-tests
right frontal and parietal cortex are involved in learning to identify concealed objects in naturalistic surroundings. Furthermore, they suggest that the application of anodal tDCS over these regions can greatly increase learning, resulting in one of the largest effects on learning yet reported.
Effects also found for Right Parietal
Karim, A. A., Schneider, M., Lotze, M., Veit, R., Sauseng, P., Braun, C., & Birbaumer, N. (2010). The truth about lying: Inhibitioin of the anterioir prefrontal cortex improves deceptive behavior. Cerebral Cortex, 20: 205-213.
In this arrangement, active electrode (known as G1) is placed on the belly of the muscle and reference electrode (known as G2) on the tendon. The ground electrode is usually placed between the stimulating and recording electrodes. (http://neurologysimplified.blogspot.com/2008/09/recording-electrodes-for-motor-studies.html)
\
Image from :
Acute Changes in Motor Cortical Excitability During Slow Oscillatory and Constant Anodal Transcranial Direct Current Stimulation
Til Ole Bergmann, Sergiu Groppa, Markus Seeger, Matthias Mölle, Lisa Marshall, Hartwig Roman Siebner
Journal of Neurophysiology Published 1 October 2009 Vol. 102 no. 4, 2303-2311 DOI: 10.1152/jn.00437.2009
"Blausen 0103 Brain Sensory&Motor" by BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work. Licensed under CC BY 3.0 via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Blausen_0103_Brain_Sensory%26Motor.png#/media/File:Blausen_0103_Brain_Sensory%26Motor.png
"Human motor map" by Michael Graziano - emailed peresonally. Licensed under CC BY-SA 1.0 via Wikipedia - https://en.wikipedia.org/wiki/File:Human_motor_map.jpg#/media/File:Human_motor_map.jpg
"Spinal cord tracts - English" by Polarlys and Mikael Häggström - File:Medulla spinalis - tracts - English.svg by Polarlys (translation by Selket).. Licensed under CC BY-SA 3.0 via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Spinal_cord_tracts_-_English.svg#/media/File:Spinal_cord_tracts_-_English.svg
Nitsche & Paulus J Physiology (2000)
Boxes indicate 25th and 75th percentiles
Error Bars indicate 10th and 90th percentiles
MEPs recorded in Abductor Digiti minimi (ADM) muscle
Ag/AgCl electrodes in a belly tendon arrangement
Neuroscan system (Neuroscan Inc., Herndon, VA, USA)
Time indicates last significant timepoint at indicated stimulus duration
35cm^2 electrodes
Fig. 1. After-effects of cathodal tDCS. Time course of changes in MEP amplitude evoked by a standard TMS pulse following termination of 5 – 9 min
polarisation with a 1 mA DC current.
Error bars are SEM
35 cm^2 electrodes
No effect for cathodal!
This is in accordance with tDCS-generated hyperpolarization
of the neuron leading to inactivation of the relevant
voltage-gated channels and therefore negation of any
drug effect.
Cathodal tDCS hyperpolarization inactivation of Ca2+/Na+ voltage gated channels no drug effect
Lynch, M. A. (2004). Long-term potentiation and memory. Physiological Reviews 84(1): 87-136.
Ca activations Calcium dependent kinases which control AMPA and NMDA receptor trafficking
This is in accordance with tDCS-generated hyperpolarization
of the neuron leading to inactivation of the relevant
voltage-gated channels and therefore negation of any
drug effect.
tDCShyperpolarizationinactivation of Na+/Ca2+ voltage gated channelsno drug effect
Error bars are SEM
35 cm^2
Binds at glycine binding site
100mg dosage of CYC beneificicial for Alzheimer’s disease
Fregni et al. (2014). Regulatory considerations for the clinical and research use of transcranial direct current stimulation (tDCS): Review and recommendations from an expert panel. Clinical Research and Regulatory Affairs, [Early Online]: 1-14.
Fregni et al, Clinical Research and Regulatory Affairs (2014)
“Out of 172 articles, 56% mentioned adverse effects and 63%
reported at least one adverse effect”
“when they were systematically assessed, the rates of common adverse
effects did not differ between the active arms of the studies and the sham arms.”
Most studies did not systematically assess
Erythema = skin reddening
“Due to an increase in blood flow of dermal vessels accompanying the current application”
Might be ameliorated by pre-treatment topical Ketoprofen (NSAID w/ analgesic and antipyretic effects, inhibits production of prostaglandin)
Rare skin burns resulting from incorrect application (prep of skin, humidifcation of sponges, limit of voltage)
Serious Adverse events
“According to the FDA, and similarly to other international
regulatory agencies, serious adverse events are those in which
the outcome is (i) death, (ii) life-threatening, (iii) hospitalization,
(iv) disability/permanent damage, (v) congenital
anomaly/birth defect, (vi) required intervention to prevent
permanent impairment or damage (for implantable devices),
(vii) and other serious events—e.g. refractory seizures,
cardiorespiratory arrest, anaphylactic reaction etc.”
Fregni et al, Clinical Research and Regulatory Affairs (2014)
Fregni et al, Clinical Research and Regulatory Affairs (2014)
“non-invasive procedure in the
standard medical usage of this term, meaning that it does not
involve penetrating the skin or a body cavity”
Fregni et al, Clinical Research and Regulatory Affairs (2014)
This does not imply going beyond these parameters is not safe, but we can not say for sure.
Fregni et al, Clinical Research and Regulatory Affairs (2014)
The safety and efficacy of daily to twice-daily, domiciliary,
30-min, 1–3-mA tDCS sessions across nearly 3 years was
reported in a patient with schizophrenia
Medical Device
“According to the US
Food and Drug Administration (FDA) (27), a medical device is
defined as: ‘‘An instrument, apparatus, implement, machine,
contrivance, implant, in vitro reagent, or other similar or
related article, including a component part, or accessory’’ that
is recognized for the use in diagnosis, prevention, and
treatment in humans without using chemical pathways.”
REGARDLESS OF USAGE INDICATION
“nearly all noninvasive or cutaneously administered electrical stimulationdevices have been deemed Class II medical devices by the FDA”
Investigational Device Exception (IDE) Approval
“allows for human research pending controls, documentation, and monitoring by both the manufacturer and investigator.”
Every clinical trial with tDCS requires an IDE approval from FDA
EXCEPT those clinical trials that receive a NSR exception from their IRB, resulting in an expedited IDE by FDA
NSR designation overwhelmingly applied by both IRBs and FDA (when asked)
NeuroConn and Soterix Medical have IDE for tDCS
Minimal risk
“Minimal risk means there have been no
serious adverse events, that common adverse effects such as
reddening of the skin are mild and short-lived, and that
reasonable efforts at assessment have determined there is no
evidence of brain damage.”
DEVICE x PROTOCOL designation
If it were significant-risk
May still be approved if “benefits offset risk and/or appropriate measures are taken to control risk”
Clearance
Absence of manufacturer application
Fregni et al, Clinical Research and Regulatory Affairs (2014)
Nitsche, M. A., & Paulus, W. (2011). Transcranial direct current stimulation – update 2011. Restorative Neurology and Neuroscience, 29:463-492.