Basal Ganglia Flashcards
Function of the Basal Ganglia
cognitive, emotional, movement related functions
Striatum
Caudate Nucleus + Putamen
Lentiform Nucleus
Globus Pallidus + Putamen
Caudate Nucleus
motor function, emotional reward and procedural/associative learning
Internal Capsule
afferent and efferent white matter tracts between thalamus and cortex
Putamen
regulate movements and influence learning
Globus Pallidus
regulation of voluntary movement
- ventral pallidum: involved in planning and inhibiting movements
Nucleus Accumbens
integrates motivation with motor action
caudate head + putamen - only visible before thalamus/3rd ventricle
Subthalamic Nuclei
Usually inactive due to inhibition from GPe (no inhibition = Parkinson's disease) - Dorsolateral motor territory - Medial Limbic Territory - Ventromedial associative territory
Dorsolateral Motor Territory
inputs/outputs, function
(subthalamic nuclei)
input: primary motor cortex
output: GPe, GPi
motor function
Medial Limbic Territory
inputs/outputs, function
(subthalamic nuclei)
input: anteriro cingulate cortex
output: GP ventral pallidum
behavioral, emotional
Ventromedial Associative Territory
inputs/outputs, function
(subthalamic nuclei)
input: prefrontal cortex frontal eye fields
output: SNr
oculomotor, cognitive
Where in the brain are there the most dopamine neurons
Substantia Nigra
also Ventral tegmental area
Substantia Nigra pars Compacta
- input to BG, supplies dopamine to striatum
contains densely packed, pigmented dopaminergic neurons
Substantia Nigra pars Reticulata
- output from BG
contains loosely packed, non pigmented inhibitory GABAergic neurons
Nucleus Accumbens - Shell
- limbic system connections
- project to ventral tegmental area, hypothalamus, amygdala
- part of mesolimbic pathway (reward system)
Nucleus Accumbens - Core
- motor function related to reward/reinforcement
- project to globus pallidus, substantia nigra
Nigrostriatal Pathway
connections between dopamine neurons of SNc and striatum
- production of movement
Basal Ganglia input
straitum receives input from cerebral cortex, SNc
Basal Ganglia output
SNr to thalamas, superior colliculi
GPi to thalamus to motor cortex
Motor and Oculomotor Loop
along w/ CNS regions to modulate movements prior to and during execution
Associative (cognitive) Loop
involved in regulating attention and planning
Limbic (emotional) Loop
involved in regulating emotional behaviors and motivation
Direct Pathway
creating movement
- removes inhibition from thalamus by inhibiting GP
striatum –> GPi –> Thal
Indirect Pathway
inhibiting unwanted movement
- subthalamic nucleus inhibits thalamus
striatum –> GPe –> Sub thal. –> GPi –> Thal
Hypokinetic
loss of movement, slowness, rigidity
due to loss of direct pathway (less disinhibition of VA/VL)
- Akinesia
- Bradykinesia
Akinesia
difficulty in initiating movement
decrease of spontaneous movement
Bradykinesia
slowness of movement
Hyperkinetic
excessive//inappropriate motor activity loss of indirect pathway (less inhibition of VA/VL) - Athetosis - Chorea - Ballism
Atethosis
slow, writhing movement of distal parts of limbs
Chorea
rapid, flicking movement of extremities and facial muscles
Ballism
violent, flailing movement of limbs
Body movement pathway
motor, premotor somatosensory cortex
–> putamen –> GP –> VL/VA
Oculomotor movement pathway
posterior parietal, prefrontal cortex
–> caudate (body) –> GP, SNr –>
mediodorsal & VA nuclei
Associative pathway
dorsolateral prefrontal cortex
–> caudate (head) –> GP, SNr –>
Mediodorsal & VA nuclei
Limbic pathway
amygdala, hippocampus, orbitofrontal, anterior cingulate, temporal cortices
–> ventral striatum –> GP
mediodorsal nucleus
