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Motor Learning - Second Exam
Cerebral Cortex, Synapses, Glial Cells, Basal Nuclei, Cerebellum, Vestibular System
44
Anatomy
Undergraduate 3
07/28/2007

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Term
Primary Motor Cortex
Definition
Thin layer IV (input layer)
Thick layer V (output layer)
Giant pyramidal cells
Term
Sensory Cortex
Definition
Thick layer IV (input layer)
Thin layer V (output layer)
Term
Homotypical Cortex
Definition
All other areas besides motor and sensory cortex
All 6 layers are equally represented
Term
Pyramidal Cells
Definition
the major output cells of the cortex
Term
Layer V
Definition
Major output layer of the cortex
Giant pyramidal cells (Motor Cortex)
Projection fibers to subcortical structures and spinal cord
Term
Glial Cells
Definition
Maintain microenvironment and provide neurons with structural support
Names are different in CNS and PNS, but functions are the same
Term
CNS Glial Cells
Definition
Astrocytes - Satellite Cells
Oligodendrocytes - Schwann cells
Microglia - Macrophages
Term
PNS Glial Cells
Definition
Satellite Cells - Astrocytes
Schwann cells - Oligodendrocytes
Machrophages - Microglia
Term
Astrocytes
Definition
(PNS - Satelite Cells)
Can Replicate
Release neuromodulators
Secrete growth factors to support neurons
Provide barrier for ionic environment (help maintain it)
Term
Oligodendrocytes
Definition
(PNS - Schwann Cells)
Myelinate axons
Degeneration > Multiple Sclerosis
Term
Multiple Sclerosis
Definition
degeneration of oligodendrocytes
Term
Microglial Cells
Definition
(PNS - Macrophages)
Immune cells
Pick up debris
Secrete neurotoxic substances
Term
Satellite Cells
Definition
(CNS - Astrocytes)
surround cells in ganglia
regulate extracellular ionic environment
Term
Schwann Cells
Definition
(CNS - Oligodendrocytes)
Myelinate peripheral nerve axons
Term
Macrophages
Definition
(CNS - microglial)
Immune cells
Term
Chemical Synapse
Definition
Presynaptic cell makes neurotransmitter and packages it in synaptic vesicles in nerve terminal
Action potential causes release of neurotransmitter which diffuses across synaptic cleft and binds to receptor molecules on postsynaptic membrane
Term
Presynaptic Mechanisms
Definition
The presynaptic action potential causes depolarization of the axon terminal membrane
Voltage-gated Ca2+ channels open and Ca2+ enters cell
Intracellular Ca2+ promotes docking of synaptic vesicles to release sites
The neurotransmitter is released by exocytosis
The intracellular Ca2+ is pumped into the endoplasmic reticulum and eventually to the extracellular space
Term
Postsynaptic Terminal
Definition
NT diffuses through synaptic cleft
NT briefly binds to receptor on postsynaptic terminal on dendrite or motor end plate on muslce
NT binding causes changes in ion permeability across postynaptic cell membrane to depolarize or hyperpolarize the cell
RESULT: causes a change in the charge of the postsynaptic cell
Free NT molecules are removed from synaptic cleft
Graded potentials from many synapses summate to deterine response of cell
Term
Synapse Summary
Definition
Presynaptic cell makes NT and packages it in synaptic vesicles in nerve reminal
Action potential causes Ca2+ influx that initiates release of neurotransmitter to diffuse across synaptic celft and bind to receptor molecules on postsynaptic membrane
Neurotransmitter binding causes change in ionic permeability
Term
Result of crossing synapse
Definition
Causes change in the charge in the postsynaptic cell
Term
Cerebellar Output
Definition
Purkinje Cells (inhibitory)
Term
Cortex Output
Definition
Pyramidal Cells
Term
Purkinje Cells
Definition
Only output cell for Cerebellar Cortex
project to cerebellar nuclei
Term
Vestibulocerebellar Module
Definition
A cerebellar module
Function: Balance and Posture
Both reticulospinal and vestibulospinal tracts and nuclei are involved
Damage in central portion of cerebellum: disruption in balance and posture
Term
Damage in central portion of cerebellum
Definition
Cause disruption in balance and posture
Unsteadiness
Term
Spinocerebellar Module
Definition
A cerebellar module
Function: affects the control of axial muscles
Cerebellum can project directly to the spinal cord on its own
Term
Cerebellar Modules
Definition
Vestibulocerebellar
Spinocerebellar
Pontocerebellar
Each has: an area of crotex, white matter core, nucleus
Term
Pontocerebellar Module
Definition
A cerebellar module
Function: Planning and control of upper arm and hand; more cognitive function
Lateral parts of cerebellar cortex
Damage: cognitive loss; upper extremities; integration of sensory input and projections affect the movement patterns
red nuclei
Term
Vestibular System
Definition
Center for balance in the brain
Vestibular nuclei receive info from other areas of the body
Ability to control body and eyes relative to the external environment
Term
Vestibular receptors
Definition
3 semicircular canals - rotational movement
2 otolith organs - linear acceleration
Term
Semicircular canals
Definition
Vestibular receptor
Three
Rotational movement
Term
Otolith Organs
Definition
Vestibular receptor
Two
Linear acceleration
Term
How Vestibular Sensory Receptors Work
Definition
Hair cell sensory receptors
Head movements cause endolymph in semicircular canals and otolith organs to move and activate the hair cell receptors
Movement of hair cells in one direction cause depolarization and movement in the other direction causes hyperpolarization
Firing frequency speeds up in one direction and slows down in the other direction
Term
Endolymph
Definition
Moves hairs in semicircular canals and otolith organs causing either hyperpolarization or depolarization
Term
Endolymph
Definition
Moves hairs in semicircular canals and otolith organs causing either hyperpolarization or depolarization
Term
Vestibular Nuclei
Definition
control eyes, body, thalamus, and communicate with cerebellum
4 In pons and medulla
Term
Vestibulo-Ocular Reflex
Definition
Eyes move in equal and opposite direction of the head
Stabilizes gaze during movement
Can be suppressed (watching a plane in the sky)
Term
Vestibularspinal
Definition
Extensor control for posture
Term
What do vestibular nuclei project to?
Definition
eyes, cerebellum, spinal cord, and thalamus
Term
Basal Nuclei
Definition
Motor behavior
Sensorimotor integration
Cognitive function
Motor planning and initiation of movement

In forebrain
Receives input from and projects to cerebral cortex
Term
Disinhibition
Definition
In Basal Nuclei
Damage > when you lose basal nuclei, you lose inhibition, and excitation output is increased because of decreased inhibition
Term
Damage to Basal Nuclei
Definition
If you lesion nuclei > movement can be reduced (hypokinetic disturbances) or increased (hyperkinetic disturbances)
Damages showed from increased output from thalamus
Term
Huntington Disease
Definition
Cognitive deficits
Hereditary
Progressive
Untreatable
Too much calcium in the cells
Term
Parkinson Disease
Definition
Progressive
Tremor
Fixed Posture
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