Case 7 Flashcards
What is the role of the basal ganglia?
Initiation and execution of movement
Where are the basal ganglia based?
Base of the forebrain
What are the telencephalic elements of the basal ganglia?
Caudate nucleas, putamen, globus palladus (internal and external)
What is the diencephalic element of the basal ganglia?
Subthalamic nucleus
What is the mesencephalic element of the basal ganglia?
Substantia nigra
What is the name given to the caudate and the putamen together?
corpus striatum
what area is target of the cortical input to the basal ganglia?
corpus striatum (caudate and putamen)
What part of the basal ganglia is the output to the thalamus?
globus palladus
What neurones in the corpus striatum receives input from the cortex?
medium spiny neurones
What are the only areas of the cortex that do not project to the corpus striatum?
Primary auditory and primary visual
what part of the corpus striatum do the somatosensory and motor cortices project to?
putamen
what part of the corpus striatum does the prefrontal cortex project to?
caudate
Where do the dopaminergic inputs to the corpus striatum arise from?
substantia nigra pars compacta
What neurotransmitter is used for the cortex to the corpus striatum of the basal ganglia?
glutamate
where on the medium spiny neurones do the dopaminergic cells synapse
the base/shaft of the dendritic spines
What dopamine receptors are part of the D1 receptor family?
1 and 5
What dopamine receptors are part of the D2 receptor family?
2,3,4
What does stimulating a D1 receptor do to the adenyl cyclase activity?
Stimulates adenyl cyclase (increases effect of cortical neurones)
What does stimulating a D2 receptor do to the adenyl cyclase activity?
Inhibits (decreases effect of cortical neurones)
What neurotransmitter do the medium spiny neurones use?
GABA
What is the MAIN output of the basal ganglia? inhibitory or stimulatory
Inhibitory
what are the differences between the two populations of medium spiny neurones?
One population expresses D1 (direct pathway) and another expresses D2 (indirect pathway)
What do the medium spiny neurones of the DIRECT pathway synapse onto?
- globus pallidus internal
- substantia nigra pars reticular
What are the normal impulses of the globus pallidus internal and substantia nigra pars reticular
inhibitory
what happens when the globus pallidus internal and pars reticular are inhibited?
They send less impulses - inhibatory impulses - so in effect they become LESS INHIBITORY
where do the globus pallidus internal and pars reticular project to?
Ventral anterior and ventral lateral thalamus
what happens when the globus pallidus internal and pars reticular send less inhibitory impulses to the thalamus?
the thalamus is able to send more stimulatory impulses to the cortex.
what happens when the globus pallidus internal sends more inhibitory impulses to the thalamus?
the thalamus sends less stimulatory to the cortex
What pathway is the globus palidus external involved in?
Indirect
what pathway is the subthalamic nucleus involved in?
indirect
What does the balance between excitation and inhibition mean of the basal ganglia?
They either facilitate or inhibit the descending pathways
What is the dopaminergic pathway called that connects the pars compacta and the basal ganglia?
Nigrostriatal pathway