Corticobulbospinal Tracts & Basal Ganglia Motor Systems II Flashcards
baseline activity
can increase or decrease-change in frequency of APs
disinhibition
removal of inhibitory effect of stimulus
basal nuclei
subcortical grey matter
components of basal nuclei
striatum (caudate + putamen)globus pallidus (external and internal)nucleus accumbenssubthalamic nucleussubstantia nigra
lentiform nucleus
putamen and globus pallidus
GPe and GPi
globus pallidus internal and externalinternal - medialexternal - lateral
division of substantia nigra
pars compacta - dopamine-lost in parkinsons Dxpars reticulata
basal nuclei arrangement
paired parallel circuits
role of basal nuclei
determine what behavior is appropriate
direct pathway
yes pathway-basal nuclei > cortex
indirect pathway
no pathway-basal nuclei > cortex
basal nuclei
balance of direct vs. indirect pathway
3 kinds of behavior through basal nuclei
motorcognitionaffect (emotion)not vision / audition**
seen rostrally
nucleus accumbensappears to connect caudate and putamen
input to basal nuclei
striatum
output of basal nuclei
GPi and SNrinfluence cortex via thalamus
to striatum
motor activitycognitive processes - prefrontalemotional behavior - limbic
caudate
cognitive processes
ventral striatum
emotional behaviors
putamen
motor activity
basal nuclei blood supply
branches of anterior cerebral artery - caudate head and nucleus accumbensbranches of middle cerebral artery (lenticulostriate ) - lentiform and striatumbranches of posterior cerebral artery - substantia nigra and subthalamic nucleus
basal nuclei pathology
movement disorders-don’t affect strength, coordination, or sensationaffect voluntary systems**
akinetic
without movement
negative sign
reduced movement
positive sign
increased movement
hypokinesia
reduced movement
bradykinesai
slow movement
dyskinesia
inappropriate movements
tremor
oscillatory movement-at rest, decreased with voluntary movement
athetosis
slow, writhing movement
chorea
abrupt, rapid, jerking, dance-like movements
choreoathetosis
overlap of athetosis and chorea
ballism
violent jerking of one limbusually unilateral - hemiballismus
parkinsons
cause unknowndegeneration of SNclack in melanin containing dopaminergic neurons
Sx of parkinsons
hypokinesia and bradykinesia-negative signs-gait - small shuffle steps-facial masking - no facial communication-tremor and rigidity-positive signsloss of postural reflexes-close eyes, shove, can’t recover
substantia nigra compacta
drives cortex-increase direct loop-decrease indirect loop
parkinsons therapy
L-dopa-doesn’t work long termreplace missing cells-will get killed toodeep brain stimulation
huntingtons disease
earlier onset - age 30-40multiple CAG repeats on chromosome for protein huntungtin-results in cell deathautosomal dominant
pathology of huntingtons
degeneration of striatum-loss of cholinergic neurons
Sx of huntingtons
hyperkinesias-choreoathetosisdementia and cognitive changeslittle treatmenthallucinations/paranoia