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PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
PPT - UMass Boston Computer Science: Home
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PPT - UMass Boston Computer Science: Home

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  • The nerves of peripheral nervous system connect the CNS to muscles, glands, blood vessels and all the organs of the body including the sense organs. The function of this nervous system is to carry messages from the brain to all the other parts of the body, and back from these parts to the brain and the spinal cord.
    Autonomic Nervous System The autonomic nervous system is also known as the involuntary nervous system, as it controls all the involuntary actions of the body. These nerves connect the CNS to the cardiac muscles, internal organs and the glands. The autonomic nervous system can be further sub-divided in to:Sympathetic Nervous System The sympathetic nervous system is also referred to as the 'flight or fight system', as it prepares our body for emergencies. It results in increased heart beat, high blood pressure and brings about other changes by the release of adrenaline, that prepares us to face danger or stress.
    Parasympathetic Nervous System The Parasympathetic Nervous System on the other hand has just the opposite effect. It helps in calming and relaxing the body and ensures proper functioning of the digestive system. Hence, it is also known as the 'Rest and Digest System'. It dilates the pupil, restores normal blood pressure and heart beat.
  • Cajal: Spanish anatomist who provided early depictions of neurons using Golgi staining.
  • Transcript

    • 1. Introduction to Cognitive Science Lecture 4: Neuroscienc e: An Neuroscience:Neuroscience: An OverviewAn Overview September 17, 2009
    • 2. A Quick Tour of Neuroscience The Nervous System The Neuron The Action Potential Synaptic Transmission Methods of Studying Neuronal Activity Basic Neuroanatomy
    • 3. The Nervous System Central & Peripheral Nervous Systems Unconscious, e.g., heart rate, sweating PNS: nervous system outside CNS SUBDIVISIONS: •Somatic: nerves innervate skin, joints, and muscles (axons in PNS while somas in CNS) •Autonomic Autonomic Nervous System (part of PNS)CNS: brain & Spinal Cord
    • 4. The Neuron: Basic Structure
    • 5. Santiago Ramón y Cajal (1852-1934) “The Neuron Doctrine” Neurons are the most basic functional units in the brain which communicate with one another via contact and not continuity.
    • 6. Basic Structure of a Neuron Nucleus: Cellular organelle that contains DNA Soma: Cell Body Collateral Axon Schwann Cells: Make myelin Myelin Sheath: Membraneous wrapping around axons made by Schwann cells (PNS) or oligodendroglia (CNS) Dendrites: Receive signals from other neurons (sometimes the same neuron!) Node of Ranvier: Space between two myelin-sheaths where axon is exposed Axon Terminal Arbor: Branches at end of the axon that terminate in the same region of the nervous system Saltatory Conduction: In myelinated neurons, the action potential skips along the nodes of Ranvier resulting in faster conduction Axon Hillock: Electrical trigger zone at the beginning of the axon
    • 7. Ways of Describing Neurons
    • 8. By Neurite Shape or Number (axons and dendrites) BipolarBipolar UnipolarUnipolar Multi-polarMulti-polar PyramidalPyramidal
    • 9. By Connections • Primary Sensory Neurons: receive information from neurites in sensory surfaces such as skin or retina • Motor Neurons: send messages from central nervous system to other areas • Interneurons: neurons that are neither sensory or motor neuron; can also describe CNS neurons whose axons do not leave the structure in which they reside
    • 10. By Neurotransmitter Neurotransmitter: A chemical released by a presynaptic area at axon terminii upon stimulation and activates post- synaptic dendrites •Amino Acids: e.g. glutamate, Gamma-Amino Acids: e.g. glutamate, Gamma- aminobutyric acid (GABA)aminobutyric acid (GABA) •Monoamines: e.g.Monoamines: e.g. Serotonin:Serotonin: AcetylcholineAcetylcholine Epinephrine (Adrenaline)Epinephrine (Adrenaline) Norepinephrine (Nor-Adrenaline)Norepinephrine (Nor-Adrenaline) •Others:Others: AcetylcholineAcetylcholine AdenosineAdenosine Nitric OxideNitric Oxide PeptidesPeptides AND LOADS MORE!!AND LOADS MORE!!
    • 11. The Action Potential A Brief fluctuation in membrane potential caused by the rapid opening and closing of voltage-gated ion channels. Action potentials sweep down axons to transfer information from one place to another in the nervous system.
    • 12. Neuronal Firing Patterns • Tonic: some neurons are always active and fire constantly • Phasic: neurons fire in bursts
    • 13. Synaptic Transmission
    • 14. Methods for Studying Neurons
    • 15. Neuronal Firing: Intracellular RecordingsNeuronal Firing: Intracellular Recordings • Impale neuron or axon with a microelectrode (veryImpale neuron or axon with a microelectrode (very challenging)challenging) • Measure potential difference between the tip of theMeasure potential difference between the tip of the intracellular electrode and another electrode in theintracellular electrode and another electrode in the solution bathing the neuron.solution bathing the neuron. • Intracellular electrode is filled with KCl salt solutionIntracellular electrode is filled with KCl salt solution which has high electrical conductivitywhich has high electrical conductivity • Electrode connected to an amplifier; can view potentialElectrode connected to an amplifier; can view potential differences on an oscilloscope (voltmeter). Voltagedifferences on an oscilloscope (voltmeter). Voltage changes can be heard as a popping sound.changes can be heard as a popping sound. Movie:Movie: http://www.youtube.com/watch?v=IgUMdwa1_Ushttp://www.youtube.com/watch?v=IgUMdwa1_Us
    • 16. Fluorescent Proteins: Study Neuron Shape & Development • Get neurons to express GreenGet neurons to express Green Fluorescent protein (GFP) as aFluorescent protein (GFP) as a markermarker • Can study neuron shape andCan study neuron shape and growthgrowth • If GFP is spliced (entered) intoIf GFP is spliced (entered) into DNA near where a specific geneDNA near where a specific gene of interest resides:of interest resides: Both the gene product and GFPBoth the gene product and GFP are expressed togetherare expressed together
    • 17. Electroencephalogram (EEG) Electroencephalography (EEG) is aElectroencephalography (EEG) is a non-invasive technique for detectingnon-invasive technique for detecting and localizing electrical activities of theand localizing electrical activities of the central nervous system. EEG systemscentral nervous system. EEG systems measure the electric potentials inducedmeasure the electric potentials induced on the surface of the scalp usingon the surface of the scalp using electrodes.electrodes. USESUSES •Clinical: localization of focal epilepsyClinical: localization of focal epilepsy sources, psychiatrysources, psychiatry •Research: to analyze sensorimotor orResearch: to analyze sensorimotor or cognitive functions of the brain.cognitive functions of the brain.
    • 18. Functional Magnetic Imaging (fMRI) • Type of MRI that studies blood flow responses to neuronal activity • Can study responses to specific visual or auditory stimuli or performance of a cognitive task. • Here are areas where neural activation was greater when listening to sentences using incorrect syntax vs correct syntax (blue) • And when the auditory recordings were intelligible vs untintelligible Obesler, et. Al.Obesler, et. Al. Disentangling Syntax and Intelligibility in AuditoryDisentangling Syntax and Intelligibility in Auditory Language Comprehension, Human Brain Mapping (2009)Language Comprehension, Human Brain Mapping (2009)
    • 19. Major Brain Regions
    • 20. Left and Right HemispheresLeft and Right Hemispheres The human brain consists of two hemispheres thatThe human brain consists of two hemispheres that are more or less mirror images of each other inare more or less mirror images of each other in terms of their physical shape.terms of their physical shape. Functionally, however, there are some symmetriesFunctionally, however, there are some symmetries but also asymmetries.but also asymmetries. Symmetries exist in the processing of low-levelSymmetries exist in the processing of low-level sensory input and motor control, where the leftsensory input and motor control, where the left hemisphere is responsible for the right half of thehemisphere is responsible for the right half of the body and vice versa.body and vice versa. One striking asymmetry is that the ability toOne striking asymmetry is that the ability to understand and produce language is much moreunderstand and produce language is much more pronounced in the left than in the right hemisphere.pronounced in the left than in the right hemisphere.
    • 21. Left and Right HemispheresLeft and Right Hemispheres Decades ago, a common treatment of epilepsy wasDecades ago, a common treatment of epilepsy was to cut the corpus callosum, which is the mainto cut the corpus callosum, which is the main connection between the hemispheres, in order toconnection between the hemispheres, in order to limit the spreading of epileptic activity.limit the spreading of epileptic activity. These split-brain patients typically behaved and feltThese split-brain patients typically behaved and felt like healthy people in everyday life situations.like healthy people in everyday life situations. In laboratory experiments, however, theIn laboratory experiments, however, the consequences of the functional separation of theirconsequences of the functional separation of their hemispheres can be demonstrated.hemispheres can be demonstrated.
    • 22. Split-Brain PatientsSplit-Brain Patients If the image of an object is presented in their leftIf the image of an object is presented in their left visual field, they cannot tell the experimenter thevisual field, they cannot tell the experimenter the identity of the object.identity of the object. This is because this visual information is processedThis is because this visual information is processed only in the right hemisphere, which cannot produceonly in the right hemisphere, which cannot produce language.language. They could pick that object from a set of itemsThey could pick that object from a set of items placed outside their visual field using their left handplaced outside their visual field using their left hand (controlled by the right hemisphere) but not their(controlled by the right hemisphere) but not their right one.right one. Patients can name objects presented in their rightPatients can name objects presented in their right visual field and pick them with their right hand, butvisual field and pick them with their right hand, but not with their left one.not with their left one.

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