basal ganglia Flashcards
what is are the primary subdivisions of the striatum and their respective secondary subdivision?
primary subdivision: doral striatum ( secondary sub divion = caudate and putamen) and the ventral striatum ( nucleus accumbens )
what is are the primary subdivisions of the globus pallidus and their respective secondary subdivision?
1˚: external segment, internal segment ( 2˚: outer and inner portion)
what is are the primary subdivisions of the substantia nigra and their respective secondary subdivision?
1˚:pars compacta,
1˚:pars reticulata ( 2˚ pars lateralis)
what is the most common neuron in the basal ganglia and where specifically is it found?
the medium spinal stellate neuron and it is found in both the striasome (caudate and putamen) and the matrix
what are the main input structures in the basal ganglia and where do they receive projections from?
the striatum: caudate and putamen, and the subthalamic nucleus
they receive direct input from the cerebral cortex
what are the main output structures of the basal ganglia and where do they project to ?
the globus palidus : internal segment and the substantia: nigra pars reticulata
they project back to the cerebral cortex via the thalamus
what are e.g.s of intermediate structures that modify the activity of input or output structures?
substantia nigra pars compacta and the subthalamic nucleus
Where is dopamine made?
in the substantia nigra pars compacta
cognition IS supported by basal ganglia true or false?
TRUE
Depending on the receptor type dopamine can be _ ______ or ________
a positive influence or negative influence
what does dopamine receptor d1 do?
increase adenylate cyclase therefore increasing excitation and turns the brake off ( the thalamus is the brake)
what does dopamine receptor D2 do?
it is inhibitory and decreases adenylate cyclase and ramps the brake up ( it is the indirect pathway) ( the thalamus is the brake)
what does releasing the brake in the bicyle analogy mean?
disinhibition i.e. excitation as seen in the direct pathway with D1 receptor
the subthalamic nucleus is rich in ______ and therefore ______________ the brake
glutamate ( which is excitatory and therefore ramps up the brake) ( the brake is the thalamus )
D1 receptors are always doing what to the thalamus?
inhibiting it
what are the 2 motor loops in the basal ganglia?
the body movement loop and the oculomotor loop
describe the body movement loop
1.starts in the primary , premotor, and somatosensory corticies
- putamen
- lateral globus pallidus, internal segment,
- ventral lateral and ventral anterior nuclei
- cortical targets
describe the oculomotor loop
1.starts in the posterior parietal lobe and prefrontal cortex
2. goes to the caudate
3. globus pallidus, internal segment, substantia nigra pars reticulata
4 mediodorsal and ventral anterior nuclei
5. cortical targets