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22 Cards in this Set
- Front
- Back
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Motor components of basal ganglia
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putamen, caudate, GP, SN(c and r)
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Input basal ganglia
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from all cortex except primary visual and auditory via thalamic relays
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output
basal ganglia |
to GP and SNr VL/VA
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blood supply to the basal ganglia
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MCA (medial striate, lenticulostriate, anterior choroidal aa)
PCA and posterior communicating aa |
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Striatum
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caudate + putamen
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major type of neurons that project out of striatum, inhibitory neurons with lots of dendritic spines for synaptic input
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Medium spiny neurons
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Medium spiny neurons project to
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GP and SNr, either contain GABA+ sub P (direct loop) or GABA + enkephalin (indirect loop)
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- Ach-containing neurons = degenerate in
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Huntington’s disease
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Striatum components
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striosomes (AChesterase poor), matrix (enkephalin and AChesterase rich), somatopopic org
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Striatum input
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corticostriate fibers (from cortex), nigrostriate fibers (dopaminergic projections from SNc ->destruction leads to Parkinson’s disease), thalamostriate fibers (from intralaminal thalamic nuclei), projections from subthalamic nucleus and from dopaminergic retrorubral area
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o Nigrostriatal projections
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inhibitory or excitatory via D1/D2 overall increases the initated motor activity through facilitation of the direct loop and inhibition of indirect loop
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o Mesolimbic dopaminergic system
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involved in responses to rewarding stimuli
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Basal Ganglia Function
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segregated input from sensorimotor, association, and limbic cortex
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- PUTAMEN involved in
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motor functions (supplementary motor, premotor, primary motor cortex-> putamen -> GP and VA/VL -> supplementary motor, premotor, primary motor cortex)
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- CAUDATE – involved in
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cognitive aspects of behavior (association areas caudage GP and DM/VA prefrontal areas)
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- VENTRAL STRIATUM (nucleus accumbens) – involved in
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motivational aspects of behavior (limbic info -> ventral striatum -> DM -> anterior cingulate and orbitofrontal cortex)
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- Direct Loop involved in
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activation of putamen inhibits GPi (which normally inhibits thalamocortical communication) ->disinhibition so thalamocortical communications can occur -> increase in motor activity
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- Indirect Loop involved in
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activation of putamen inhibits GPe (which normally inhibits subthalamic nucleus) ->disinhibition of subthalamic nucleus (which normally activates GPi) -> activation of GPi -> increased inhibition of thalamocortical communication -> decrease in motor activity
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- Dopaminergic neurons – EXCITE
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direct loop via D1 receptors and INHIBIT indirect loop via D2 receptors
10) Disorders |
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- Parkinson’s – degeneration of
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dopaminergic neurons in SNc (nigrostiatal pathway)
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pallidotomy
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surgical removal of GP which takes away inhibition of thalamocortical communications
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- Huntington’s – degeneration in
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ACh neurons in straitum, especially caudate
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