basal ganglia Flashcards
how basal ganglia select output
the best output based on practice and reward
name 6 parts of basal ganglia, one has 2 segments and a grouping name
caudate nucleus
putamen
striatum = caudate + putamen
nucleus accumbens = junction of puta/caudate
globus pallidus (internal and external)
subthalamic nucleus
substantia nigra
parts of thalamus for basal ganglia
Ventral posterior lateral sends output to S1
Ventral Lateral and Ventral Anterior send output to motor, recieve from basal ganglia
Describe direct/GO pathway in basal
Cortex excites striatum (which gets +/- from substantia nigra)
striatum inhibits GP internal
GP inhibits thalamus
less inhibition on thal allows GO
Describe indirect/STOP pathway basal
striatum sends inhibition to GP external
GP external inhibits GP internal
GP internal inhibits thalamus
inhibiting GP external means less inhibition on internal, meaning more inhibition on thalamus, STOPs thalamus
Motor loop basal
does practiced/fluid motion
M1 -> Putamen -> GO/STOP -> thalamus -> M1
Cognitive Loop basal
active in training periods, learning
association cortices -> Caudate & Nucleus accumbens -> GO/STOP -> Thalamus -> cortices
Limbic Loop basal
emotions control/expressiveness
Limbic/amygdala/hippocampus -> Caudate & Nucleus accumbens -> GO/STOP -> Thalamus -> Limbic
Huntington’s Disease
death in striatum
signs = loss of cog/emotion control and chorea late sign
too much GO, death of striatum means no inhibition on GP external (death of stop pathway), means too much inhibit intenral, so no inhibition of thalamus
Parkinson’s Disease
loss od dopaminergic cells in substantia nigra
treated with dopamine drugs or deep brain stim of basal
symptoms = akinesia, resting tremor, muscle rigidity
no substantia nigra = TOO much STOP, striatum inhibits too much of GP external, meaning no inhibition on GP internal, so internal inhibits thal too much
