direct and indirect pathways Flashcards
discuss components of direct pathway
cortex → striatum → GPi and substantia nigra pars reticulata → thalamus (VA and VL) for motor control and back towards the motor cortex
discuss of flow of NT in direct pathway
cortex release glutamate to excite striatum
striatum release GABA that stops release of GABA in GPi and SNr = less GABA = disinhib of thalamus
thalamus releases glutamate = stim of motor cortex
function of direct pathway
disinhibs thalamic control = initiation of movement = excite motor cortex
discuss components of indirect pathway
cortex → striatum → GPe → subthalamic nucleus/subthalamus → GPi and substantia nigra pars reticulata → thalamus (VA and VL) for motor control and back towards the motor cortex
discuss of flow of NT in indirect pathway
cortex releases glutamate = striatum releases more GABA = inhibits GPe
GPe releases GABA = subthalamic nuc to release glutamate = exctites GPi and SNr
GPi and SNr releases GABA without stim kaya w stim releases more = inhib thalamus = no more glutamate
function of indirect pathway
Disinhibition of subthalamus = Decreased activity of motor cortex = Removal of excess unwanted movement
what is the net effect of direct and indirect pathway
coordinated and smooth movement
exp hyperdirect pathway
Activates STN directly from motor cortex without intervening striatum = inhibitory
receptor of D1 and D2
striatum
most implicated in diseases of the basal ganglia
D1 and D2
receptor of D3
nucleus accumbens
receptor of D4
frontal cortex and certain limbic structures
D5
hippocampus and limbic system
compare D1 and D2 in terms of effect
D1 - excitatory
D2 - inhibitory
what does D1 stimulate
adenyl cyclase abd direct pathway
