Basal Ganglia Flashcards
Basal ganglia
collection of five subcortical nuclei involved in movement caudate putamen globus pallidus subthalamic nucleus substantia nigra
Basic pathway
input in from most of cortex
projects back to frontal part of cortex through the thalamus
Most input to the basal ganglia is received in the _
striatum (caudate + putamen)
Most projections from striatum are to _
globus pallidus and substantia nigra
Lenticular nucleus
globus pallidus and putamen
Functional divisions of globus pallidus
internal segment (GPi) external segment (GPe)
Two parts of substantia nigra
pars compacta (SNc) pars reticulata (SNr)
Main projections of the basal ganglia to the thalamus come from the _ and reach the _
GPi and SNr
VL and VA
Two pathways from struatum to GPi
direct pathway
indirect pathway
Ansa leticularis
thick fibre bundle
conveys info from GPi to motor thalamus
Lenticular fasciculus
conveys info from caudal side of globus pallidus to the VA/VL nuclei of the thalamus
Thalamic fasciculus
bundle of fibres headed for the VA/VL of the thalamus
includes ansa fasciculus, lenticular fasciculus and other cerebellothalamic fibres
Four cortic-basal loops
Motor
Cognitive
Limbic
Occulomotor
Basal ganglia affect the ipsa- or contra-lateral motor cortex/movements of the body
Ipsalateral motor cortex
therefore contralateral movements of the body
Consequence of the direct pathway
increase in excitatory drive from thalamus to cortex
