Flashcards in Basal ganglia Deck (27)
what are the roles of the basal ganglia?
1. inhibit involuntary movements at rest 2. facilitate voluntary movements
what are the five basal ganglia?
1. caudate nucleus 2. putamen 3. globus pallidus 4. subthalamic nucleus 5. substantia nigra or, corpus striatum + substantia nigra + subthalamic nucleus
what makes up the lentiform nucleus?
putamen + globus pallidus
what makes up the corpus striatum?
caudate + lentiform
what makes up the striatum?
putamen + caudate nucleus
the caudate is primarily concerned with what function?
the putamen is primarily concerned with what function?
what are the major inputs to the striatum?
1. corticostriate 2. thalamostriate 3. nigrostriatal
what are the outputs from the striatum?
1. striatopallidal 2. striatonigral (pars reticulata)
what are the inputs to the pallidum?
1. striatopallidal 2. subthalamic fasciculus
what is the thalamic fasciculus?
1. the common tract joining the lenticular fasciculus + ansa lenticularis as they travel from the pallidum to the thalamus (VA and VL nuclei) 2. also carries cerebellar fibers to same nuclei
what are the outputs from the pallidum?
1. pallidothalamic 2. pallidosubthalamic 3. pallidonigral 4. thalamocortical
what are the "reciprocal connections" of the basal ganglia?
1. striatum - substantia nigra 2. pallidum - subthalamic
what are the four loop circuits of the basal ganglia? what information do they convey?
1. motor - UMNs of corticospinal, corticonuclear tracts 2. association - planning and direction 3. oculomotor - integration of eye movements and visual guidance 4. limbic - emotional and motivational
what is the conserved pathway of the loop circuits of basal ganglia?
cortex - striatum - pallidum - thalamus
what are the roles of the VA / VL and mediodorsal nuclei or the thalamus?
1. VA / VL - relay signals related to movement 2. mediodorsal - relay signals to frontal and limbic cortex
what is the direct pathway through the basal ganglia? what is the result?
1. facilitates flow of information through the thalamus 2. results in greater excitation of cortex, and voluntary movement (due to release of the thalamus from the tonic pallidal inhibition)
what is the indirect pathway through the basal ganglia? what is the result?
1. decreases activity in the thalamus 2. lessens excitatory output to the cortex, and tonically suppresses inappropriate movements (also terminates volitional movements)
what is the "input gate" to the basal ganglia?
what is the "output gate" from the basal ganglia?
what serves as the interface between the basal ganglia and the cortex?
is the thalamus excitatory or inhibitory to the cortex?
is the pallidum excitatory or inhibitory to the cortex?
what is the proximate cause of Parkinson's disease?
death of dopaminergic cells in pars compacta of substantia nigra
what is athetosis?
slow, involuntary, convoluted, writhing movements of fingers, hands, toes, and feet
what is hemiballismus?
appearance of flailing, ballistic, undesired movements caused primarily by a decrease in activity in the subthalamic nucleus