Motor Control II Flashcards
how is the overall movement direction encoded?
Each neurone has a preferred direction but responses of all neurons are combined to produce a population vector
what adjustments are made before movements begin?
anticipatory feedforward adjustments
what initiates feedforward anticipatory adjustments to stabilize posture?
brainstem reticular formation nuclei (controlled by the cortex)
what does cortical damage cause?
causes immediate flaccidity of contralateral muscles. Lift limb and release-drops passively
what is the babinski sign?
(normal adult, plantar flexion)
baby and cortical damage, extension – both indicate incomplete upper control of spinal circuits
describe Spasticity
increased muscle tone, hyperactive stretch reflex – due to removal of cortical suppressive influences
where does Major subcortical input to area 6 come from?
ventral lateral nucleus(VLo) in dorsal thalamus
what does the Basal ganglia motor loop do?
selects and initiates willed movements
describe the Basal ganglia motor loop
cycles via - cortex through basal ganglia and thalamus(VLo) - back to SMA in cortex
what is the input zone of the basal ganglia?
Corpus striatum - includes 2 principal nuclei the caudate and the putamen
what is the corticostriatal pathway?
multiple parallel pathways with different functions
when do the caudate and the putamen fire?
putamen fires before limb/trunk movements
caudate fires before eye movements
both are predictive of movements
what is glutamatergic?
excitatory axons
what is gabaergic?
axons are inhibitory
where do putamen and caudate project?
globus pallidus and to substantia nigra pars reticulata