Basal Ganglia Flashcards
the corpus striatum has ______ subdivisions. The neostriatum is _______ divided into 2 parts by the __________
- 3
- one nucleus
- ant. limb of internal capsule
what separates the globus palladius ?
internal medullary lamina
What do the GPe and GPi stand for?
GPe external
GPi internal
what are the2 parts of the neo striatum?
caudate nucleus
Putamen
What are the 3 parts of the corpus striatum?
Striatum
Globus pallidus
Amygdaloid nuclear complex
Where does the amygdaloid complex develop from?
Telencephalon, but is functionally associated with Limbic system
what 2 other structures are FUNCTIONALLY related to basal ganglia?
- sub thalamic nuclei
2. Substantia Nigra
What are the 4 sub thalamic nuclei?
VA
VL
DM
CM
what are the 2 parts of Substantia nigra and what neurons do they have?
- Pars compacta SNc - dopamine, black pigment
2. Pars reticularis SNr - GABA neurons
What other structures are ANATOMICALLY related to corpus striatum?
- lentiform nucleus
globus pallidus and Putamen - Claustrum: bounded by external and extreme capsules
what nucleus plays a role in coordination of synergistic movements?
Pedunculopontine nucleus
- sets up a rhythmic cholinergic input to striatum
T/F: then basal ganglia connects widespread areas of the cortex with circumscribed parts of motor cortex, limbic cortex, or frontal lobe association.
true
what is the function of the caudate nucleus?
cognitive function/processing
what is the function of the putamen?
Motor function
- habit formation
what does the dorsal vs. ventral striatum do?
dorsal: involved with caudate and putamen
Ventral: involved with limbic system and emotion
what is the difference between indirect and direct circuits?
Direct: facilitates motor activity
Indirect: Inhibits motor activity
what is the nigrostriatal pathway?
What fibers are involved?
- dopamine containing fibers from SNc to striatum &
- GABA fibers from Striatum back to SNc
T/F: theres direct output of basal ganglia to spinal cord LMN, but not to brainstem
False
No direct efferent pathways
what are the major efferents?
GPe and SNr
-They go to thalamic nuclei
what other efferent modulates the tectospinal pathway? Any others?
SNr
the primary mechanism underlying function of basal ganglia is _____. Inhibition of a _______. How is this accomplished?
- disinhibition
- tonically active inhibitory pathway
- by a balance of signals from direct and indirect circuits, conversion on output nuclei GPi and SNr
what are the cells in the GPi linked to?
remembered motor tasks
what is the direct circuit pathway?
widespread areas of cortex (glutamate) –> striatum (GABA) –> GPi and SNr (GABA) –> thalamic nuclei (glutamate) –> frontal lobe cortex
what is the indirect circuit pathway?
widespread areas of cortex –> striatum –> GPe (GABA) –> subthalmic nuclei –> frontal lobe cortex
what are the cells in the GPi linked to?
thalamus
T/F: cells of GP are not spontaneously active as they are controlled by cortical (nigral) activation of quiet stratal cells (caudate & putamen)
False
-spontaneous
What is the 2nd function of the basal ganglia? What does it mean for an Alzheimers pt?
Procedural learning,
- ability to learn and replicate automatic motor skills
Alzheimers patients can learn new motor tasks, but not new facts.
what is the blood supply of the basal ganglia?
striatal and ganglionic arteries
what are the 3 hyperkinetic disorders?
Athetosis
Choreas
Ballismus
what is Athetosis?
(oriental dancer)
what is Choreas
jerking movements.
what is Ballismus?
violent flinging movements
What is the hypothesis for these 3 hyperkinetic disorders?
indirect circuit is cut and permits direct circuit to drive movements unopposed
What is the one Hypokinetic disorder?
parkinson disease
what happens with Parkinson?
degeneration of nigrostriatal/dopaniergic neurons.
What is the hypothesized mechanism for parkinsons?
Loss of control over UMN (Frontal cortex) results in loss of voluntary control of alpha LMN
