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19 Cards in this Set
- Front
- Back
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What are the basal ganglia and what is their principle function?
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Not ganglia at all but rather nuclei (groups of cell bodies within CNS) located at the base of the forebrain
Motor "gatekeeper" theory of function: basal ganglia has net inhibitory effect on motor systems, release of this inhibition permits a motor system to become active |
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What structures make up the basal ganglia?
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Striatum (caudate and putamen), globus pallidus/pallidum (GPi and GPe), substantia nigra (SNc and SNr) and the subthalamic nucleus (STN)
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What structures make up the forebrain?
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The cerebrum and the diencephalon together make up the forebrain.
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What structures make up the diencephalon?
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Thalamus, subthalamus, hypothalamus, epithalamus
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What two structures is the striatum divided into?
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Caudate nucleus (caudate) and putamen
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What structure appears to separate the caudate and putamen?
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Internal capsule
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What is the mesencephalon?
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The midbrain
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What and where is the substantia nigra (SN)?
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Mesencephalonic gray matter
Divided into substantia nigra reticulata (SNr) and substantia nigra pars compacta (SNc) |
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Does the thalamus tonically inhibit or excite the motor cortex?
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The thalamus tonically excites the motor cortex.
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Does the cerebral cortex tonically excite or inhibit the striatum?
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The cerebral cortex tonically excites the striatum.
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Does the SNr/GPi complex tonically inhibit or excite the thalamus?
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The SNR/GPi complex tonically inhibits the thalamus
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Describe the direct pathway through the basal ganglia:
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Cerebral cortex excites striatum, striatal inhibition of the SNr/GPi complex increases (inhibition of the inhibitor), SNr/GPi complex inhibition of thalamus is lowered, thalamic excitation of motor cortex is released, net hyperkinetic state
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Does the striatum tonically excite or inhibit the SNr/GPi complex?
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The striatum tonically inhibits the SNr/GPi complex (inhibits the inhibitor).
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Does the GPe tonically excite or inhibit the STN?
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The GPe tonically inhibits the STN.
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Does the STN tonically excite or inhibit the SNr/GPi complex?
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The STN tonically excites the SNr/GPi complex (excites the inhibitor)
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Describe the indirect pathway through the basal ganglia:
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Cerebral cortex excites the striatum, striatal inhibition of the GPe increases, GPe inhibition of the STN decreases, STN excitation of the SNr/GPi complex increases, SNr/GPi inhibition of thalamus increase, thalamic excitation of cerebral cortex is dampened
Cerebrum --> Striatum --> GPe --> STN --> SNr/GPi complex --> Thalamus --> Cerebrum Net effect: hypokinetic state |
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What is the lentiform nucleus?
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Refers to the putamen (of the caudate) and the globus pallidus (or pallidum) within the basal ganglia
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Is the putamen lateral or medial to the internal capsule?
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Lateral
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Is the caudate lateral or medial to the internal capsule?
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Medial
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