This study seeks to analyze the molecular basis of circadian rhythms and behavioral modulation by hormones in the nudibranch Melibe leonina. The goals are to localize circadian clock neurons in the central nervous system using immunohistochemistry, stain for the neurotransmitters conopressin and melatonin, and assess behavioral responses to injections of these hormones through video recordings. Understanding the relationship between clock neurons, hormones, and behavior can provide insights into circadian rhythm regulation applicable to fields like medicine.
Neuron based time optimal controller of horizontal saccadic eye movementsAlireza Ghahari
A neural network model of biophysical neurons in the midbrain for controlling oculomotor
muscles during horizontal human saccades is presented. Neural circuitry that includes
omnipause neuron, premotor excitatory and inhibitory burst neurons, long lead burst neuron,
tonic neuron, interneuron, abducens nucleus and oculomotor nucleus is developed to
investigate saccade dynamics. The final motoneuronal signals drive a time-optimal
controller that stimulates a linear homeomorphic model of the oculomotor plant.
Sensorimotor Network Development During Early Postnatal Life in the Awake and...InsideScientific
In the last decades, electrophysiological and imaging-based approaches provided significant new insights into the mechanisms of neuronal development. Nevertheless, many important questions remain unanswered. How does the fine control of a motor output develop? How does sensorimotor integration in the early and subsequent phases of brain development shape behavior? How does sensorimotor development evolve in awake and sleeping states? What role do myoclonic twitches play in this process?
Answering these questions requires performing high-precision tests in the brain of non-anesthetized animals across sleep and wake during the early stages of their postnatal development. Such tests require head-fixation apparatus suitable for neonatal and juvenile rodents. The Mobile HomeCage combines a stable head-fixation with an air-lifted cage that closely resembles laboratory rodents’ natural habitat – an optimal platform for studying early postnatal brain development.
In this webinar, Dr. Cavaccini (Prof. Karayannis’s lab at the Brain Research Institute, University of Zurich) and Dr. Dooley (Prof. Blumberg’s lab at the University of Iowa), share their insights into the development of rodent sensorimotor neuronal circuits during early postnatal life. They elucidate the cortical and subcortical mechanisms involved in the development of sensorimotor circuitry during wakefulness (in a mouse model) and REM sleep (in a rat model).
Key Takeaways
Dr. Anna Cavaccini:
- Anatomical and functional changes occur at the striatal level before and after the onset of different sensory modalities
- Locomotor activity changes throughout early development, and it correlates with striatal function
- Sensory information coming from whiskers affects locomotion and striatal function before and after the onset of different sensory modalities
Dr. James Dooley:
- Myoclonic twitches in REM sleep continue to trigger cortical and thalamic activity beyond the early postnatal period
- Twitch-related thalamic activity is spatiotemporally refined by the third postnatal week
- Motor thalamus activity reflects an internal model of movement produced by twitches and is dependent on the cerebellar output
Monitoring neural activities by optical imagingMd Kafiul Islam
Monitoring neural activities by optical imaging along with the use of genetic modification provides better spatio-temporal resolution to study single neural firing and hence very useful in understanding the neural process and dynamics. This is just a glimpse of few articles reported their outcome of such imaging.
Electrophysiology of Human Native Receptors in Neurological and Mental DisordersInsideScientific
Dr. Agenor Limon presents research integrating functional metrics with large anatomical, transcriptomic, and proteomic datasets to evaluate the relationship between synaptic E/I ratio and behavioral abnormalities across postmortem intervals and brain banks.
Alterations in synaptic function have been found in transcriptomic, genetic, and proteomic studies of neurological and mental disorders. Clinical and preclinical studies suggest that synaptic dysfunction and behavioral abnormalities in disorders like Alzheimer’s disease and schizophrenia may be mechanistically linked to the emergence of imbalances between excitatory (E) and inhibitory (I) receptors. However, until recently, the electrophysiological E/I synaptic ratio had only been measured in animal models.
Using pioneering methods developed in the lab including reactivation and microtransplantation of synaptic receptors from frozen human brains, Dr. Agenor Limon’s research team has obtained electrophysiological metrics of global synaptic E/I ratios in cortical brain regions of subjects that were affected by Alzheimer’s Disease and synaptic measurements in schizophrenia.
In this webinar, Dr. Agenor Limon will present recent research integrating functional metrics with large anatomical, transcriptomic, and proteomic datasets to evaluate the relationship between synaptic E/I ratio and behavioral abnormalities across postmortem intervals and brain banks.
Key Topics Include:
- Understand the global synaptic excitation to inhibition ratio between excitatory and inhibitory synaptic receptors determined from reactivated frozen human brain tissue
- Understand the relationship between electrophysiological metrics of receptor function and multi-omic data in neurodegenerative disorders
- Understand the role of deviations of the excitation to inhibition ratio with clinical presentation in Alzheimer’s disease
This document discusses neuronal plasticity, which refers to the brain's ability to change and adapt as a result of experience. It describes various types and mechanisms of neuroplasticity, including enhancement of existing connections through synapse development and strengthening, and formation of new connections through unmasking of silent synapses and axon sprouting. It also discusses cortical remapping in deaf individuals and long-term potentiation as the basis of neuronal plasticity. Synaptic plasticity can be measured in the hippocampus, where strong stimulation leads to calcium influx and activation of protein kinases that strengthen synapses.
Edgardo J. Arroyo is an Associate Research Scientist at Yale University School of Medicine who has extensive experience researching various aspects of myelin formation, degradation, and regeneration in the central and peripheral nervous systems. His research has focused on elucidating the cellular mechanisms and microanatomy of neuron-glial interactions using techniques such as immunohistochemistry, confocal microscopy, and biochemistry. He has studied topics such as the effects of spinal cord injury, stem cell transplantation, sodium channel expression after nerve damage, and how demyelination affects the molecular organization of nodes of Ranvier.
This document discusses motor learning and recovery of function. It covers several key points:
1) Motor learning involves the acquisition and modification of movement skills through practice and is enabled by neural plasticity in the brain.
2) Neural plasticity allows for both short-term and long-term changes in synaptic connections that support motor learning and recovery of function after injury.
3) Recovery of function involves both functional changes like unmasking existing connections as well as structural changes such as remapping of sensory or motor cortex.
4) Motor learning can be declarative, requiring conscious effort, or non-declarative and automatic, through mechanisms like classical conditioning, sensitization, and procedural learning.
This document discusses how the brain controls body movements and transfers information. It argues that an intact body with sensory feedback is essential for maximal brain control and information transfer. It provides evidence that: 1) Volitional control of neurons drops when proprioceptive feedback is disrupted. 2) Proprioception and other senses are needed for normal movements. 3) Intact sensory feedback is required for learning through experience. 4) Current brain-machine interfaces transfer far less information than an intact brain due to reduced feedback. The body provides crucial feedback that allows the brain to effectively generate movements and learn from the environment.
Neuron based time optimal controller of horizontal saccadic eye movementsAlireza Ghahari
A neural network model of biophysical neurons in the midbrain for controlling oculomotor
muscles during horizontal human saccades is presented. Neural circuitry that includes
omnipause neuron, premotor excitatory and inhibitory burst neurons, long lead burst neuron,
tonic neuron, interneuron, abducens nucleus and oculomotor nucleus is developed to
investigate saccade dynamics. The final motoneuronal signals drive a time-optimal
controller that stimulates a linear homeomorphic model of the oculomotor plant.
Sensorimotor Network Development During Early Postnatal Life in the Awake and...InsideScientific
In the last decades, electrophysiological and imaging-based approaches provided significant new insights into the mechanisms of neuronal development. Nevertheless, many important questions remain unanswered. How does the fine control of a motor output develop? How does sensorimotor integration in the early and subsequent phases of brain development shape behavior? How does sensorimotor development evolve in awake and sleeping states? What role do myoclonic twitches play in this process?
Answering these questions requires performing high-precision tests in the brain of non-anesthetized animals across sleep and wake during the early stages of their postnatal development. Such tests require head-fixation apparatus suitable for neonatal and juvenile rodents. The Mobile HomeCage combines a stable head-fixation with an air-lifted cage that closely resembles laboratory rodents’ natural habitat – an optimal platform for studying early postnatal brain development.
In this webinar, Dr. Cavaccini (Prof. Karayannis’s lab at the Brain Research Institute, University of Zurich) and Dr. Dooley (Prof. Blumberg’s lab at the University of Iowa), share their insights into the development of rodent sensorimotor neuronal circuits during early postnatal life. They elucidate the cortical and subcortical mechanisms involved in the development of sensorimotor circuitry during wakefulness (in a mouse model) and REM sleep (in a rat model).
Key Takeaways
Dr. Anna Cavaccini:
- Anatomical and functional changes occur at the striatal level before and after the onset of different sensory modalities
- Locomotor activity changes throughout early development, and it correlates with striatal function
- Sensory information coming from whiskers affects locomotion and striatal function before and after the onset of different sensory modalities
Dr. James Dooley:
- Myoclonic twitches in REM sleep continue to trigger cortical and thalamic activity beyond the early postnatal period
- Twitch-related thalamic activity is spatiotemporally refined by the third postnatal week
- Motor thalamus activity reflects an internal model of movement produced by twitches and is dependent on the cerebellar output
Monitoring neural activities by optical imagingMd Kafiul Islam
Monitoring neural activities by optical imaging along with the use of genetic modification provides better spatio-temporal resolution to study single neural firing and hence very useful in understanding the neural process and dynamics. This is just a glimpse of few articles reported their outcome of such imaging.
Electrophysiology of Human Native Receptors in Neurological and Mental DisordersInsideScientific
Dr. Agenor Limon presents research integrating functional metrics with large anatomical, transcriptomic, and proteomic datasets to evaluate the relationship between synaptic E/I ratio and behavioral abnormalities across postmortem intervals and brain banks.
Alterations in synaptic function have been found in transcriptomic, genetic, and proteomic studies of neurological and mental disorders. Clinical and preclinical studies suggest that synaptic dysfunction and behavioral abnormalities in disorders like Alzheimer’s disease and schizophrenia may be mechanistically linked to the emergence of imbalances between excitatory (E) and inhibitory (I) receptors. However, until recently, the electrophysiological E/I synaptic ratio had only been measured in animal models.
Using pioneering methods developed in the lab including reactivation and microtransplantation of synaptic receptors from frozen human brains, Dr. Agenor Limon’s research team has obtained electrophysiological metrics of global synaptic E/I ratios in cortical brain regions of subjects that were affected by Alzheimer’s Disease and synaptic measurements in schizophrenia.
In this webinar, Dr. Agenor Limon will present recent research integrating functional metrics with large anatomical, transcriptomic, and proteomic datasets to evaluate the relationship between synaptic E/I ratio and behavioral abnormalities across postmortem intervals and brain banks.
Key Topics Include:
- Understand the global synaptic excitation to inhibition ratio between excitatory and inhibitory synaptic receptors determined from reactivated frozen human brain tissue
- Understand the relationship between electrophysiological metrics of receptor function and multi-omic data in neurodegenerative disorders
- Understand the role of deviations of the excitation to inhibition ratio with clinical presentation in Alzheimer’s disease
This document discusses neuronal plasticity, which refers to the brain's ability to change and adapt as a result of experience. It describes various types and mechanisms of neuroplasticity, including enhancement of existing connections through synapse development and strengthening, and formation of new connections through unmasking of silent synapses and axon sprouting. It also discusses cortical remapping in deaf individuals and long-term potentiation as the basis of neuronal plasticity. Synaptic plasticity can be measured in the hippocampus, where strong stimulation leads to calcium influx and activation of protein kinases that strengthen synapses.
Edgardo J. Arroyo is an Associate Research Scientist at Yale University School of Medicine who has extensive experience researching various aspects of myelin formation, degradation, and regeneration in the central and peripheral nervous systems. His research has focused on elucidating the cellular mechanisms and microanatomy of neuron-glial interactions using techniques such as immunohistochemistry, confocal microscopy, and biochemistry. He has studied topics such as the effects of spinal cord injury, stem cell transplantation, sodium channel expression after nerve damage, and how demyelination affects the molecular organization of nodes of Ranvier.
This document discusses motor learning and recovery of function. It covers several key points:
1) Motor learning involves the acquisition and modification of movement skills through practice and is enabled by neural plasticity in the brain.
2) Neural plasticity allows for both short-term and long-term changes in synaptic connections that support motor learning and recovery of function after injury.
3) Recovery of function involves both functional changes like unmasking existing connections as well as structural changes such as remapping of sensory or motor cortex.
4) Motor learning can be declarative, requiring conscious effort, or non-declarative and automatic, through mechanisms like classical conditioning, sensitization, and procedural learning.
This document discusses how the brain controls body movements and transfers information. It argues that an intact body with sensory feedback is essential for maximal brain control and information transfer. It provides evidence that: 1) Volitional control of neurons drops when proprioceptive feedback is disrupted. 2) Proprioception and other senses are needed for normal movements. 3) Intact sensory feedback is required for learning through experience. 4) Current brain-machine interfaces transfer far less information than an intact brain due to reduced feedback. The body provides crucial feedback that allows the brain to effectively generate movements and learn from the environment.
This document discusses neuroplasticity and brain recovery after stroke. It explains that strokes interrupt blood flow to the brain, damaging neurons. While some neurons die immediately, others may survive in the penumbra region with reduced blood flow. The brain has mechanisms for recovery, including remapping of neural connections to compensate for lost functions. Recovery is best facilitated by early rehabilitation that takes advantage of increased neuroplasticity shortly after the stroke. Stem cell therapies also show promise for replacing lost neurons but have safety challenges.
This document discusses neuroplasticity and recovery after spinal cord injury. It classifies spinal cord injuries and explains that neuroplasticity refers to the brain's ability to form new neural connections. It provides examples of cortical reorganization and plasticity in the brain after injuries like amputation or spinal cord injury. The document also discusses how sensory feedback training and treadmill training can enhance neuroplasticity and promote recovery of locomotion through reorganization of spared pathways in the spinal cord.
Mirror neurons are a class of neurons in the monkey premotor cortex that discharge both when the monkey performs an action and when it observes another individual performing a similar action. The review discusses evidence that a mirror neuron system exists in humans and plays a fundamental role in action understanding and imitation learning. It proposes that the human mirror neuron system may be linked to and help explain the evolution of human language capabilities.
This study investigated differences in the density of nitric oxide synthase (NOS) interneurons in the striatum between individuals with Tourette Syndrome (TS) and normal controls (NC). Brain tissue from 5 TS and 5 NC individuals was stained using immunohistochemistry to label NOS interneurons. The staining procedure and a pilot study to determine the most effective antibody were described. Sections from each brain were analyzed under a microscope using the Optical Fractionator probe method to count and compare NOS interneuron densities in the caudate nucleus and putamen between groups. It was hypothesized that NOS interneuron density would be decreased in the striatum of individuals with TS.
This document discusses voluntary motor control and the brain regions involved. The basal ganglia and cerebellum help modulate and plan movement. Within the basal ganglia, different regions receive input and output to different motor areas in a somatotopic organization. The cerebellum contains somatotopic maps and is divided into vestibulocerebellum, neocerebellum, and spinocerebellum. The primary motor cortex codes for force and direction of movement. Premotor areas encode sensorimotor transformations and fire before movement based on visual or sensory cues. Mirror neurons in the premotor cortex fire both when performing and observing specific motor acts.
The Brain as a Whole: Executive Neurons and Sustaining Homeostatic GliaInsideScientific
Carl Petersen and Alexei Verkhratsky share their research on homeostatic neuroglia and imaging of neuronal network function. This webinar is brought to you by APS’ new journal, Function, and part of their Physiology in Focus learning series.
During this exclusive live webinar, Carl Petersen and Alexei Verkhratsky discuss astrocyte-mediated homeostatic control of the central nervous system, and how optical and 2-photon microscopy can be used for functional neuroimaging.
Imaging Neuronal Function
Carl Petersen, PhD
Highly dynamic and spatially distributed neuronal circuits in the brain control mammalian behavior. Through technological advances, optical measurements of neuronal function can now be carried out in behaving mice at multiple scales. Wide-field imaging allows the dynamic interactions between different brain areas to be studied as sensory information is processed and transformed into behavioral output. Within a brain region, two-photon microscopy can be used to image the neuronal network activity with cellular resolution allowing different types of projection neurons to be distinguished. Together optical methods provide versatile tools for causal mechanistic understanding of neuronal network function in mice.
Astrocytes: indispensable neuronal supporters in sickness and in health
Alexei Verkhratsky, MD, PhD, DSc
The nervous system is composed of two arms: the executive neurons and the homeostatic neuroglia. The neurons require energy, support, and protection, all of which is provided by the neuroglia. Astrocytes, the principal homeostatic cells of the brain and spinal cord, are tightly integrated into the neural networks and act within the context of the neural tissue. As astrocytes control the homeostasis of the central nervous system at all levels of organization, from the molecular to the whole organ level, we can begin to define and understand brain vulnerabilities to aging and diseases.
Neural oscillations occur throughout the central nervous system and can be measured at different scales: microscopic (single neuron), mesoscopic (local groups of neurons), and macroscopic (between brain regions). At the microscopic level, neurons generate action potentials that form rhythmic spike trains. Groups of synchronized neurons give rise to local field potential oscillations. Interactions between brain areas also produce large-scale oscillations measured by EEG. Different neural oscillations have been linked to cognitive functions like perception and memory.
It provides a brief information about Neuroplasticity to enthusiast willing to know "How we gain daily skills?" and "Changing ability of our brain according to our daily habit."
For more details on study, you can follow the references...
Neuroplasticity refers to the brain's ability to change and adapt in response to experience. It allows for strengthening and weakening of nerve connections and even the growth of new nerve cells. All areas of the brain show some degree of plasticity, even in adulthood, contrary to previous beliefs. Experiences shape the brain by stimulating synaptogenesis, synaptic pruning, and changes in neuronal connectivity. Neuroplasticity enables learning, recovery from injury, and adaptation to environmental changes throughout life.
This study examined mirror neurons in macaque monkeys through electrophysiological recordings. The researchers recorded from 37 mirror neurons in the F5 region of the monkeys' brains. They found that mirror neurons responded both when the monkey performed hand actions like grasping and when they observed the experimenter perform the same actions. Mirror neurons responded more strongly during the late movement and holding periods of the observed actions. The results support the hypothesis that mirror neurons are involved in action recognition. The study provides evidence that mirror neurons encode the meaning and intention of observed actions.
This document contains three annotated bibliographies summarizing research articles:
The first summarizes a study finding that intracellular gold nanoparticles increase neuronal excitability and seizure activity in mice brains. The second describes research using an automated maze to assess hippocampus-sensitive memory in mice. The third summarizes a study using magnetic resonance imaging to find age-dependent axonal transport deficits in a mouse model of frontotemporal dementia.
Neuroplasticity, the brain's ability to change and form new connections, is key to recovery after spinal cord injury. Repeated sensory feedback training can enhance motor responses by changing synaptic activity in the spinal cord. Studies show that complete spinal cord injuries can sometimes recover limited voluntary control of walking with intensive locomotor training stimulating the spinal cord's pattern generators, demonstrating the potential for neuroplasticity after injury. Strategies like treadmill training, pharmacology, and regenerative techniques aim to further promote plasticity and improve functional recovery.
Modulation of theta phase sync during a recognition memory taskKyongsik Yun
1) The study examined changes in theta phase synchronization across the brain during a recognition memory task using electroencephalography.
2) They found that theta phase synchronization was stronger between the frontal and left parietal areas during correct recognition of previously viewed objects compared to identifying new objects.
3) Specifically, theta phase synchronization between these regions increased from 400-1100ms after stimulus onset for recognized objects, suggesting recognition memory involves interaction between the frontal and left parietal cortices mediated by theta phase synchronization.
Neuroplasticity refers to the brain's ability to change and adapt throughout life in response to experiences. There are two main types of neuroplasticity - structural, involving physical changes to neurons and synapses, and functional, involving changes in neural pathways and connections that underlie learning and memory. Structural neuroplastic changes include synaptic plasticity, synaptogenesis, neurogenesis, and neural cell death. Functional changes are mediated by synaptic plasticity mechanisms like long-term potentiation and long-term depression. Neuroplasticity allows the brain to form new memories and skills, but can also contribute to cognitive decline or altered motor control depending on the circumstances.
Internal state dynamics shape brainwide activity and foraging behaviorTomoya Koike
This study found that zebrafish larvae exhibit two distinct behavioral states - exploitation and exploration - which are encoded by distinct neural populations across the brain. Whole-brain calcium imaging identified neuronal clusters that correlated with each behavioral state. In particular, neurons in the dorsal raphe encoded the exploitation state, showing persistent elevated activity that predicted the duration of exploitation behavior. In contrast, exploration-state neurons were activated during exploration but did not influence its duration. The study provides evidence that distinct neuromodulatory systems, including serotonergic and cholinergic neurons, are involved in encoding the different behavioral states.
The role of vasopressin in light-induced c-Fos expression in the SCNJane Chapman
- Light exposure at night causes rapid induction of the immediate early gene c-Fos in the suprachiasmatic nucleus (SCN), which is implicated in shifting circadian rhythms.
- A population of retinal projections to the SCN express the neuropeptide vasopressin (VP), but the physiological significance is unknown.
- This study investigated whether VP released from retinal neurons mediates light-induced c-Fos expression in the SCN. Rats pre-treated with a VP antagonist before light exposure still showed c-Fos expression in the SCN, with no significant decrease. This suggests VP is not essential for generating light-induced c-Fos expression in the SCN.
Molecular mechanisms that control circadian rhythms - Mohammed Elreishi Mohammed Elreishi
Circadian rhythms are driven by an internal
biological clock that anticipates day/night cycles to
optimize the physiology and behavior of organisms.
The 2017 Nobel Prize in Physiology or Medicine is
awarded to Jeffrey C. Hall, Michael Rosbash and
Michael W. Young for their Discoveries of Molecular Mechanisms Controlling the Circadian Rhythm.
The researchers constructed a neural circuit in the computer simulation Swimmy to model the central pattern generator controlling a fish's swimming activity. They identified 8 neurons involved through experiments manipulating each neuron's activity. They concluded the circuit uses a mutually depressing inhibition oscillator mechanism, where two generator neurons (cells 23 and 11) directly inhibit each other through synaptic depression, controlling the firing patterns of the other neurons and generating the swimming rhythm. This allowed the simulated fish Swimmy to move its tail in alternating motions during swimming.
This document discusses neuroplasticity and brain recovery after stroke. It explains that strokes interrupt blood flow to the brain, damaging neurons. While some neurons die immediately, others may survive in the penumbra region with reduced blood flow. The brain has mechanisms for recovery, including remapping of neural connections to compensate for lost functions. Recovery is best facilitated by early rehabilitation that takes advantage of increased neuroplasticity shortly after the stroke. Stem cell therapies also show promise for replacing lost neurons but have safety challenges.
This document discusses neuroplasticity and recovery after spinal cord injury. It classifies spinal cord injuries and explains that neuroplasticity refers to the brain's ability to form new neural connections. It provides examples of cortical reorganization and plasticity in the brain after injuries like amputation or spinal cord injury. The document also discusses how sensory feedback training and treadmill training can enhance neuroplasticity and promote recovery of locomotion through reorganization of spared pathways in the spinal cord.
Mirror neurons are a class of neurons in the monkey premotor cortex that discharge both when the monkey performs an action and when it observes another individual performing a similar action. The review discusses evidence that a mirror neuron system exists in humans and plays a fundamental role in action understanding and imitation learning. It proposes that the human mirror neuron system may be linked to and help explain the evolution of human language capabilities.
This study investigated differences in the density of nitric oxide synthase (NOS) interneurons in the striatum between individuals with Tourette Syndrome (TS) and normal controls (NC). Brain tissue from 5 TS and 5 NC individuals was stained using immunohistochemistry to label NOS interneurons. The staining procedure and a pilot study to determine the most effective antibody were described. Sections from each brain were analyzed under a microscope using the Optical Fractionator probe method to count and compare NOS interneuron densities in the caudate nucleus and putamen between groups. It was hypothesized that NOS interneuron density would be decreased in the striatum of individuals with TS.
This document discusses voluntary motor control and the brain regions involved. The basal ganglia and cerebellum help modulate and plan movement. Within the basal ganglia, different regions receive input and output to different motor areas in a somatotopic organization. The cerebellum contains somatotopic maps and is divided into vestibulocerebellum, neocerebellum, and spinocerebellum. The primary motor cortex codes for force and direction of movement. Premotor areas encode sensorimotor transformations and fire before movement based on visual or sensory cues. Mirror neurons in the premotor cortex fire both when performing and observing specific motor acts.
The Brain as a Whole: Executive Neurons and Sustaining Homeostatic GliaInsideScientific
Carl Petersen and Alexei Verkhratsky share their research on homeostatic neuroglia and imaging of neuronal network function. This webinar is brought to you by APS’ new journal, Function, and part of their Physiology in Focus learning series.
During this exclusive live webinar, Carl Petersen and Alexei Verkhratsky discuss astrocyte-mediated homeostatic control of the central nervous system, and how optical and 2-photon microscopy can be used for functional neuroimaging.
Imaging Neuronal Function
Carl Petersen, PhD
Highly dynamic and spatially distributed neuronal circuits in the brain control mammalian behavior. Through technological advances, optical measurements of neuronal function can now be carried out in behaving mice at multiple scales. Wide-field imaging allows the dynamic interactions between different brain areas to be studied as sensory information is processed and transformed into behavioral output. Within a brain region, two-photon microscopy can be used to image the neuronal network activity with cellular resolution allowing different types of projection neurons to be distinguished. Together optical methods provide versatile tools for causal mechanistic understanding of neuronal network function in mice.
Astrocytes: indispensable neuronal supporters in sickness and in health
Alexei Verkhratsky, MD, PhD, DSc
The nervous system is composed of two arms: the executive neurons and the homeostatic neuroglia. The neurons require energy, support, and protection, all of which is provided by the neuroglia. Astrocytes, the principal homeostatic cells of the brain and spinal cord, are tightly integrated into the neural networks and act within the context of the neural tissue. As astrocytes control the homeostasis of the central nervous system at all levels of organization, from the molecular to the whole organ level, we can begin to define and understand brain vulnerabilities to aging and diseases.
Neural oscillations occur throughout the central nervous system and can be measured at different scales: microscopic (single neuron), mesoscopic (local groups of neurons), and macroscopic (between brain regions). At the microscopic level, neurons generate action potentials that form rhythmic spike trains. Groups of synchronized neurons give rise to local field potential oscillations. Interactions between brain areas also produce large-scale oscillations measured by EEG. Different neural oscillations have been linked to cognitive functions like perception and memory.
It provides a brief information about Neuroplasticity to enthusiast willing to know "How we gain daily skills?" and "Changing ability of our brain according to our daily habit."
For more details on study, you can follow the references...
Neuroplasticity refers to the brain's ability to change and adapt in response to experience. It allows for strengthening and weakening of nerve connections and even the growth of new nerve cells. All areas of the brain show some degree of plasticity, even in adulthood, contrary to previous beliefs. Experiences shape the brain by stimulating synaptogenesis, synaptic pruning, and changes in neuronal connectivity. Neuroplasticity enables learning, recovery from injury, and adaptation to environmental changes throughout life.
This study examined mirror neurons in macaque monkeys through electrophysiological recordings. The researchers recorded from 37 mirror neurons in the F5 region of the monkeys' brains. They found that mirror neurons responded both when the monkey performed hand actions like grasping and when they observed the experimenter perform the same actions. Mirror neurons responded more strongly during the late movement and holding periods of the observed actions. The results support the hypothesis that mirror neurons are involved in action recognition. The study provides evidence that mirror neurons encode the meaning and intention of observed actions.
This document contains three annotated bibliographies summarizing research articles:
The first summarizes a study finding that intracellular gold nanoparticles increase neuronal excitability and seizure activity in mice brains. The second describes research using an automated maze to assess hippocampus-sensitive memory in mice. The third summarizes a study using magnetic resonance imaging to find age-dependent axonal transport deficits in a mouse model of frontotemporal dementia.
Neuroplasticity, the brain's ability to change and form new connections, is key to recovery after spinal cord injury. Repeated sensory feedback training can enhance motor responses by changing synaptic activity in the spinal cord. Studies show that complete spinal cord injuries can sometimes recover limited voluntary control of walking with intensive locomotor training stimulating the spinal cord's pattern generators, demonstrating the potential for neuroplasticity after injury. Strategies like treadmill training, pharmacology, and regenerative techniques aim to further promote plasticity and improve functional recovery.
Modulation of theta phase sync during a recognition memory taskKyongsik Yun
1) The study examined changes in theta phase synchronization across the brain during a recognition memory task using electroencephalography.
2) They found that theta phase synchronization was stronger between the frontal and left parietal areas during correct recognition of previously viewed objects compared to identifying new objects.
3) Specifically, theta phase synchronization between these regions increased from 400-1100ms after stimulus onset for recognized objects, suggesting recognition memory involves interaction between the frontal and left parietal cortices mediated by theta phase synchronization.
Neuroplasticity refers to the brain's ability to change and adapt throughout life in response to experiences. There are two main types of neuroplasticity - structural, involving physical changes to neurons and synapses, and functional, involving changes in neural pathways and connections that underlie learning and memory. Structural neuroplastic changes include synaptic plasticity, synaptogenesis, neurogenesis, and neural cell death. Functional changes are mediated by synaptic plasticity mechanisms like long-term potentiation and long-term depression. Neuroplasticity allows the brain to form new memories and skills, but can also contribute to cognitive decline or altered motor control depending on the circumstances.
Internal state dynamics shape brainwide activity and foraging behaviorTomoya Koike
This study found that zebrafish larvae exhibit two distinct behavioral states - exploitation and exploration - which are encoded by distinct neural populations across the brain. Whole-brain calcium imaging identified neuronal clusters that correlated with each behavioral state. In particular, neurons in the dorsal raphe encoded the exploitation state, showing persistent elevated activity that predicted the duration of exploitation behavior. In contrast, exploration-state neurons were activated during exploration but did not influence its duration. The study provides evidence that distinct neuromodulatory systems, including serotonergic and cholinergic neurons, are involved in encoding the different behavioral states.
The role of vasopressin in light-induced c-Fos expression in the SCNJane Chapman
- Light exposure at night causes rapid induction of the immediate early gene c-Fos in the suprachiasmatic nucleus (SCN), which is implicated in shifting circadian rhythms.
- A population of retinal projections to the SCN express the neuropeptide vasopressin (VP), but the physiological significance is unknown.
- This study investigated whether VP released from retinal neurons mediates light-induced c-Fos expression in the SCN. Rats pre-treated with a VP antagonist before light exposure still showed c-Fos expression in the SCN, with no significant decrease. This suggests VP is not essential for generating light-induced c-Fos expression in the SCN.
Molecular mechanisms that control circadian rhythms - Mohammed Elreishi Mohammed Elreishi
Circadian rhythms are driven by an internal
biological clock that anticipates day/night cycles to
optimize the physiology and behavior of organisms.
The 2017 Nobel Prize in Physiology or Medicine is
awarded to Jeffrey C. Hall, Michael Rosbash and
Michael W. Young for their Discoveries of Molecular Mechanisms Controlling the Circadian Rhythm.
The researchers constructed a neural circuit in the computer simulation Swimmy to model the central pattern generator controlling a fish's swimming activity. They identified 8 neurons involved through experiments manipulating each neuron's activity. They concluded the circuit uses a mutually depressing inhibition oscillator mechanism, where two generator neurons (cells 23 and 11) directly inhibit each other through synaptic depression, controlling the firing patterns of the other neurons and generating the swimming rhythm. This allowed the simulated fish Swimmy to move its tail in alternating motions during swimming.
The document reports on research investigating circadian rhythms in the nudibranch Melibe leonina. It was found that there are two circadian clocks: one in the brain controlling locomotion and one in the buccal ganglia controlling digestion/swallowing. Preliminary experiments showed neurons containing clock proteins CRY2 and CLK in the brain and buccal ganglia expressed independent daily activity rhythms. Future experiments aim to further characterize clock protein expression and activity of clock neurons in these regions.
The document reports on research investigating circadian rhythms in the nudibranch Melibe leonina. It was found that there are two circadian clocks: one in the brain controlling locomotion and one in the buccal ganglia controlling digestion/swallowing. Preliminary experiments showed clock proteins CRY2 and CLK are present in brain neurons, and the buccal ganglia express their own daily activity rhythm. Further experiments aim to characterize clock protein expression and neuronal activity in the two clock centers.
Circadian rhythm refers to the approximately 24-hour cycles in human and animal physiology and behavior, regulated by an internal biological clock. The master circadian clock is located in the hypothalamus, specifically the suprachiasmatic nucleus, which receives light input from the retina. These circadian rhythms evolved to protect DNA from UV radiation and help entrain organisms to the light-dark cycle. Core body temperature, melatonin secretion, and cortisol levels are classic markers used to measure circadian rhythms. Light exposure can advance or delay circadian rhythms depending on timing.
Microdialysis is an integral part of preclinical research to determine extracellular fluid and blood concentrations of metabolites, hormones, drugs, etc, and is often used in quantifying the biochemistry of brain and peripheral tissues. However, it is a molecular-only technique and other imaging modalities are needed to provide the researcher with functional and anatomical information of the animal in vivo.
Aton et al., Neuron, 2009 - Mechanisms of Sleep-Dependent Consolidation of Co...SaraAton
This study investigated the cellular mechanisms involved in sleep-dependent consolidation of ocular dominance plasticity (ODP), a form of cortical plasticity triggered by monocular deprivation. The study found that:
1) Sleep consolidates ODP primarily by strengthening responses to stimulation of the non-deprived eye.
2) Consolidation is inhibited by reversible intracortical antagonism of NMDA receptors or cAMP-dependent protein kinase during post-deprivation sleep.
3) Consolidation is associated with sleep-dependent increases in neuronal activity in visual cortex and phosphorylation of proteins required for glutamatergic synapse potentiation.
This demonstrates that synaptic strengthening via NMDA receptor and
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Similar to Allison Nash SURF proposal Melibe 2015 (20)
1. UNIVERSITY OF NEW HAMPSHIRE
COLLEGE OF LIFE SCIENCES AND AGRICULTURE
Localization of circadian clock neurons and analysis of behavioral
modulation by conopressin and melatonin in the Nudibranch Melibe leonina
Submitted by: Allison Nash
Sophomore – BMS:MLS major
9344 Granite Square Station
Durham, NH 03824
amh336@wildcats.unh.edu
Faculty Sponsor: Winsor Watson
179 Rudman Hall
(603) 862-1629
Date: February 15, 2015
2. 2
1. Abstract
Most cellular processes are regulated by circadian clock mechanisms responsible for
coordinating the metabolic and physiological activities of an organism. The Nudibranch Melibe
leonina has served as a model organism for neurobiological research of circadian rhythms and
the underlying neuronal circuitry patterns of expression and locomotion (Newcomb et al. 2014).
This project seeks to analyze the molecular basis of behavioral modulation by the circadian clock
in Melibe leonina. The first goal of the study will be to localize the clock neurons in the central
nervous system (CNS) of the Nudibranch. Sections of the brain will be stained with specific
antibodies using immunohistochemistry, and then mapped using fluorescent microscopy. The
second goal of the study will utilize the same immunohistochemistry techniques to stain for the
neurotransmitters conopressin and melatonin in the brain. The third goal of the study will be to
assess the behavioral activities of the Melibe in response to injections with each of these
hormones. Behavior will be monitored using time-lapse video recordings over 3 to 4 consecutive
24-hour light:dark (LD) cycles. The cumulative goals of the study should indicate the relation
between clock neuron functionality and the hormonal regulation of subsequent activity in the
Nudibranch.
2. Project History and Definition
Gastropods are an extremely diverse taxonomic class that includes snails, slugs, limpets
and sea hares (Holthius, 1995). Historically, the gastropod sea slug Aplysia californica has
served as a viable model organism for neurobiological research conducted by neuropsychiatrist
Eric Kandel. Kandel studied the molecular basis of memory storage in neurons by testing the
monosynaptic gill-withdrawal reflex in Aplysia (Kandel, 2006). Subsequent studies of Aplysia
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have been conducted to determine the role of the hormone conopressin. Conopressin is of
sequence homology with the hormone oxytocin, a neuromodulator in the brain, and has been
found to induce currents in molluscan neurons that function in sexual reproduction (Soest, 1998).
The study with Aplysia indicated that the vasopressin-like peptide conopressin is involved in the
regulation of the gill-withdrawal reflex at the synaptic level, that is, between the sensory and
motor neuron (Martinez-Padron, 1992).
Additional studies with the marine zooplankton Platynereis dumerilli have been conducted
to determine the role of melatonin in behavioral modulation. Melatonin is widely known to
regulate the sleep-cycle in humans, as well as other vertebrates, and has been used to treat people
that suffer from sleep disorders. This “hormone of darkness,” is secreted at night in synchronicity
with an organisms LD cycle, thereby regulating many biological functions (Tosches, 2014). The
study of zooplankton has indicated that when melatonin is released at night, it induces the firing
of neurons innervating locomotive cells, thus establishing a nocturnal swimming pattern in the
organism (Tosches, 2014).
Following the studies with conopressin and melatonin regulation in these marine
invertebrates, this research will attempt to determine how the circadian clock in the Nudibranch
Melibe leonina regulates the expression of these hormones. Melibe are soft-bodied marine slugs
that also exhibit nocturnal patterns of swimming, which have been investigated through
behavioral analysis (Watson et al. 2001). Much of behavior is regulated by hormonal secretions,
which are in turn modulated by circadian rhythms according to LD cycles for each organism.
These clock mechanisms regulate the metabolic and physiological activities of both terrestrial
and marine organisms based on 24-hour rhythms and the approximate 12-hour ebb and flow of
the tides, respectively (Wilcockson, Zhang, 2008). Behavioral analysis studies have shed light on
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the functional effect these clocks have on the locomotion of particular organisms. However, far
less is known regarding the cellular and physiological basis of these oscillators in the modulation
of behavioral expression (Newcomb et al. 2014).
As part of this study, circadian clock neurons and hormone neurotransmitters in the CNS of
Melibe leonina will be located with specialized antibodies custom made using Melibe-specific
clock protein sequences (Watson et al. 2001). The localization of clock neurons will provide
insight into any correlation between the location and corresponding function(s) of these
endogenous clock mechanisms in the regulation of hormonal secretions. Injecting the Melibe
with each of the two hormones and observing their behavior through time-lapse videos will
determine the effect these hormones have on behavior. The combination of neurobiology and
behavioral analysis will allow for a better visual of how clock neurons modulate hormonal output
and subsequent behavioral expression in the Nudibranch.
3. Approach/Methodology
Immunohistochemistry
The CNS of the Melibe leonina will be isolated through careful dissection, then fixed
and frozen. Sections will be cut using a cryostat and transferred to glass slides. Melibe-
specific clock protein sequences were used to create custom cryptochrome (CRY)
antibodies for the localization of clock neurons in the CNS of Melibe leonina. The brain
sections will be washed and blocked using a buffer solution. Then they will be diluted with
the rabbit primary antibody, specifically made to attach to the desired clock-N protein. The
slides will be washed again and diluted with the goat anti-rabbit secondary antibody, which
has a fluorescent tag attached, before being washed again and mounted for later
5. 5
examination using microscopy. The same procedure will be used to localize conopressin
and melatonin neurotransmitters in the brain with antibodies specific to each of these
hormones.
Fluorescent Microscopy
The prepared slides will be observed under a fluorescent microscope to identify the
clock neurons, which should fluoresce as bright bundles of dots under the microscope. The
staining patterns of the neurotransmitters will indicate their relative outputs and relation to
clock neurons. Images of the bundles of clock neurons and neurotransmitters will be
captured through the camera in the microscope. Slides that may not have stained well will
not be included in the final picture of the Melibe brain, but all viable sections will be
accounted for. The location of the clock neurons will be drawn on images of the brain and
presented as on a full layout of the Melibe brain to identify the particular regions of the
brain they are most present in. All pictorial representations of the clock neurons will be
compared to those completed previously, or by other lab members to ensure the most
accurate layout will be produced.
Pharmacology
The Melibe will be held in a 24-hour LD cycle for 3-4 days to assess normal behavior
using time-lapse video documentation. During the day, two Melibe will then be injected
with approximately 0.5mL of 0.1M melatonin, diluted with 0.1M sodium chloride (NaCl),
and another two will be injected with 0.1M NaCl to serve as the controls. A second set will
follow with injections of conopressin in the same amount and concentration. The behavior
of the Melibe will continue to be recorded for another 2 days to document any changes in
locomotion. Since melatonin is responsible for activating nocturnal swimming patterns in
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Melibe, it will be expected that injecting them during the day will off-set their circadian
rhythm, causing early patterns of swimming during the day.
4. Significance/Meaning/Applications
Circadian rhythms in most organisms, including humans, are responsible for maintaining
homeostasis through regulatory feedback loops, which control physiological functioning
(Wilcockson, Zhang, 2008). Regulatory behavior occurs at both the cellular and supracellular
level, and thus constitutes a fundamental aspect of animal physiology (Goldbeter, 2014). This
study takes on a traditional reductionist approach in tracing the origin of circadian regulatory
mechanisms to the intracellular level. Once the cellular basis for the functioning of clock neurons
in behavioral modulation is understood, such knowledge may be applied to broader scientific
fields such as medicine. For example, “epidemiological studies [have] demonstrated that
myocardial infarction, stroke, and sudden cardiac death, have a 24-hour daily pattern” (Ivanov et
al. 2007). Thus, determining how clock genes modulate physiological and locomotive behavior
may aid in the development of therapeutic medicine for the treatment of autonomic dysfunction
in the human body. The study conclusions are therefore applicable to further lines of research
focused on determining how disruptions of circadian rhythms may inhibit the proper
physiological functioning of organisms.
5. Personal Outcome
I am currently switching majors to Neuroscience and Behavior; thus, conducting this
research on circadian rhythms will be an invaluable experience in terms of its relation to my area
of interest. As a premed student and aspiring Neuropathologist, the medicinal application of the
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study intrigues me greatly, and working with pharmacological substances will aid in my
understanding of how they work in different organisms. Also, the experience will provide me
with a sense of how research may be conducted in medical laboratories focused on studying
diseases of the nervous system. The hands-on aspect of the study through the use of dissections
with surgical tools is also a great tool for improving dexterity, which can aid in the preparation of
slides and analysis of tissue samples.
Being awarded a SURF would provide me with the opportunity to expand my knowledge
beyond the general classroom setting, in addition to gaining direct experience with the many
facets of research, something I plan to continue in association with earning a medical degree.
Additionally, as a member of the Honors Program, I will be required to complete an Honors
Thesis my senior year. Conducting this research would provide me with grounds to base by
thesis off of in the future.
6. Location
The study will take place in Dr. Winsor Watson’s Laboratory, located in Rudman Hall on
the University of New Hampshire campus in Durham, NH. Melibe leonina specimens will be
collected off the Pacific coast by Dr. Watson’s associates, and transported to the campus
laboratory to be held in aquarium tanks.
7. My Role/Preparation/Experience
Since the start of winter break following the 2014 fall semester, I have been working in Dr.
Watson’s laboratory learning the techniques and skills necessary for conducting research in
this field of study. I participated in the dissection of the brain and ventral chord of the Atlantic
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horseshoe crab, Limulus polyphemus. I isolated and sectioned the Limulus brain using a
cryostat, and mounted the sections on slides. I then stained the slides for clock proteins using
immunohistochemistry techniques, and located the clock neurons in the protocerebrum
through fluorescent microscopy. The clock neurons were then mapped using drawing revisions
I made of the Limulus brain. Additionally, this semester I injected two Melibe with the desired
concentration of melatonin and began video recordings of their behavior. Pending
observations of this test, I will continue to research the effects these hormones have on the
behavioral patterns of the Melibe.
Localization of clock neurons and neurotransmitters in the Melibe brain will be an
extension of this research, and my experience with immunohistochemistry, fluorescent
staining/microscopy, and pharmacology has provided me with the necessary skills to proceed
with this study. As I continue research throughout the spring semester of 2015, I will be
working in loose collaboration with other undergraduate and graduate students, and extending
this research over the summer will allow for us to further our data compilation.
8. Timetable
The following table details the chronological stages of the research experiment to be
completed the summer of 2015. Some of these stages have already been started in lab to assess
the feasibility of the project and allow for repeatable tests to ensure the validity of the results.
The completion of the study will help to strengthen my application to medical school and aid
in the attainment of a career path oriented toward research in the medical field
9. 9
Experimental Stage Project Goals
1 Set up LD cycle experiment with 4
Melibe at a time. Record time-
lapse videos for 3-4 days
Assess normal behavior of the
Melibe to determine how they
express a daily rhythm
2 Inject 2 Melibe with melatonin and
2 with NaCl. Record time-lapse
videos for 2 days (repeat with
additional Melibe)
Determine how the hormone
influences the swimming behavior
and circadian rhythm of the
Melibe
3 Inject 2 Melibe with conopressin
and two with NaCl. Record time-
lapse videos for 2 days (repeat
with additional Melibe)
Determine how the hormone
influences the behavior and
circadian rhythm of the Melibe
4 Dissect and section the CNS of
the Melibe and stain for clock
neurons using the specified
antibodies
Locate the clock neurons using
fluorescent microscopy and
compare images to those
previously taken
5 Use the sections of the brain to
stain for conopressin and
melatonin neurotransmitters in the
brain
Localize the neurotransmitters in
relation to clock neurons in the
brain
6 Compile data from time-lapse
recording and images of the
Melibe brain stained for clock
neurons and hormone
neurotransmitters
Determine whether there is a
relation between the location of
clock neurons and hormonal
neurotransmitters in the brain that
influence patterns of locomotion in
the Melibe
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Appendices
Appendix 1 – Bibliography
Ivanov, P., Hu, K., Hilton, M., Shea, S., & Stanley, H. (2007). Endogenous circadian rhythm
in human motor activity uncoupled from circadian influences on cardiac dynamics. Proceedings
of the National Academy of Sciences, 104(52), 20702-20707.
Kandel, E. (2006). In Search of Memory: The emergence of a new science of mind (1st ed.).
New York: W.W. Norton &. Co.
Martinez-Padron, M., Edstrom, J., Wickham, M., & Lukowiak, K. (1992). Modulation of
Aplysia californica siphon sensory neurons by conopressin G. Journal of Experimental Biology,
2(4), 79-105.
Newcomb, J., Watson, W., Kirouac, L., Bixby, K., Lee, C., Malanga, S., & Raubach, M.
(2014). Circadian rhythm of locomotion in the nudibranch mollusc Melibe leonina. Frontiers in
Behavioral Neuroscience, 1(3), 263-273.
Soest, V., & Kits, K. (1998). Conopressin affects excitability, firing, and action potential shape
through stimulation of transient and persistent inward currents in mulluscan neurons. Journal of
Neurophysiology, 79(4), 19-32.
Tosches, M., Bucher, D., Vopalensky, P., & Arendt, D. (2014). Melatonin signaling controls
circadian swimming behavior in marine zooplankton. Developmental Biolody, 46-57.
Watson, W., Lawrence, K., & Newcomb, J. (2001). Neuroethology of Melibe leonina
swimming behavior. Integrative and Comparative Biology, 41(4), 1026-1035.
Wilcockson, D., & Zhang, L. (2008). Circatidal clocks. Current Biology, 18(17), R753-R755.