Basil Ganglia Flashcards
(25 cards)
What does subcortical mean
Subcortical = Under the cerebral cortex, which is made of gray matter
basal ganglia function
-INITIATION and EXECUTION of movement
-prevention of unwanted mvmts (inhibitory control)
-direct/ indirect pathways create desired mvmt
also: emotion, social behavior, goal directed behavior, eye mvmt
what specific parts of initiation and execution are involved in the basil ganglia
-regulation of muscle contraction
-force
-multi joint mvmt
-sequencing of mvmts
where is ALL input recived in the basil ganglia
STRIATIUM (caudate and putamen)
where does the caudate receive input from
heteromodal assosiation corticies
motor areas of frontal lobe involved in eye mvmts (eye fields?)
where does the putamen recieve input from
-sensory corticies- parietal lobe
-higher order visual corticies- occipital and temporal lobe
-premotor cortex and PriMC
-auditory association cortices- temporal lobe
what NT do subcortical structures receive input from
ACh, serotonin, NE, histamine
what are the “output” structures of the basil ganglia
VL, VA nuclei of thalamus
intralaminar nuclei of thalamus
mediodorsal nucleus
superior collicilis
what does the VL and VA nuclei of thalamus project to
frontal lobe (PriMC, premotor area, and SMA)
what does the intralaminar nuclei of thalamus project to
additional motor relay
what does the mediodorsal nucleus project to
limbic BG loop
what does thesuperior colliculus project to
eye mvmt BG loop
via tectospinal tract
explain the direct pathway of basal ganglia control
GO
background:
- GPi and SN send constant signals to thalamus to STOP mvmt
- thalamus sends constant signals to cortex to GO (mvmt)
GO:
cortex-> glu to striatum-> inhbit GPi and SN-> (inhibits inhibitor, pulling breaks off thalamus so it can GO)
explain the indirect pathway of basal ganglia control
NO GO
background:
-GPe always sending inhibitory to Subthalamatic nuclei
NO GO:
cortex-> glu to striatum-> inhibits Gpe (inhibits inhibitor)
Doubles down: cortex sends glu to subthalamatic nuclei which turns on GPi and SN-> send constant signals to thalamus to STOP mvmt
Describe dopamines roll in the basil ganglia AND what it goes through. what is it excititory and inhibitory to?
MODULATES STOP AND GO
-modulates stratum activity (THROUGH SNpc)
-excitatory to direct
-inhibitory to indirect pathways
what is the main dopamine hub
substantia nigra pars compacta
how does dopamine modulate the stop and go pathways through excititory and inhibatory pathways?
excititory-> stratum neurons in direct pathway
inhibitory-> stratum neurons in indirect pathway
describe the duel effect
Powerful decrease in suppression of thalamus by basal ganglia from dopamine affecting excitatory and inhibitory pathways
Name all of the Neuro transmitters involved it in the stop and go pathways
-dopamine
-Ach
-gaba
-glutamate
ACh role in basil ganglia
Inhibits dopamine when appropriate can quickly interrupt ongoing motor behavior in response to salient environmental stimuli
GABA, Glutamate role in basil ganglia
Primary neurotransmitters in direct and indirect pathways
explain the oculomotor loop
explain the goal directed behavior of the prefrontal loop
nonmotor
explain the limbic/emotion loop
nonmotor
