Motor 2 Flashcards
is overall movement controlled by one neuron ?
no
- integrated activity of many neurones
when there is a body position change, is there feedback messages from brain stem vestibular nuclei to the spinal cord neurones?
yes
what is feed forward mechanisms control of movement?
before a movement occurs, brain stem reticular formation nuclei make adjustments to stabilise posture
what is feed back mechanism control of movement?
after a movement occurs, information from the brain stem vestibular nuclei travels to the spinal cord to correct posture and balance
what is babinskis sign?
plantar extension
does babinskis signs show upper or lower motor neuron disease?
upper motor neuron disease
what is hypotonia?
loss of tone in muscles
- flaccid
what is the major sub cortical input to SMA of area 6?
ventral lateral nucleus in dorsal thalamus
where does the ventral lateral nucleus come from?
basal ganglion
state the 4 steps of the information loop which initiates voluntary movements
cortex -> basal ganglion -> VLo -> SMA of area 6
state the two input zones of the basal ganglia?
caudate
putamen
does corpus striatum receive input from all over the cortex?
yes
what parts of the basal ganglia receive excitatory (glutamatergic) cortical inputs?
putamen
caudate
what parts of the basal ganglia receive inhibitory (GABAergic) cortical inputs?
globus pallidus
substantia nigra
which two parts of the basal ganglia fire APs before the movement?
putamen
caudate
which two parts of the basal ganglia are predictive of movements?
putamen
caudate
what is the functional consequence of cortical activation of putamen ?
excitation
at rest are the globus pallidus neurones active or inactive ?
active
what is the direct pathway of cortical input through the basal ganglia?
cortex -> puatmen + caudate -> globus pallidus -> thalamus
then back to the cortex to the SMA
what is the indirect pathway of cortical input through the basal ganglia?
- cortex stimulate the sub thalamus nuclei
- excites the globus pallidus
- inhibits the thalamus
- cells are released from VLo (part of thalamus)
- this excites the SMA
what is the function of the direct pathway of cortical input?
selects specific motor actions
what is the function of the indirect pathway of cortical input?
suppresses competing/inappropriate action
whats the main cause of Parkinsons disease?
degeneration of neurones in substrantia nigra (SN) and their dopaminergic (excitatory) inputs to the striatum
what is the clinical complication of not being able to produce dopamine by the substantia nigra in parkinsons disease?
depletion of dopamine closes down activation of the focussed motor activities that funnel through thalamus to SMA
- difficulty making voluntary movements
what causes Huntington disease?
profound loss of caudate, putamen and globus pallidus
- so loss of the ongoing inhibitory effects of the basal ganglia
what is chorea ?
spontaneous, uncontrolled, rapid flicks and major movements with no purpose
what is the main function of the cerebellum?
regulate movement
- instructs direction, timing and force
what happens when there is a lesion on the cerebellum ?
uncoordinated inaccurate movements
via what structure does the cerebellum send information back to the cortex?
ventrolateral thalamus
state the four stages of the feedback loop involving the cerebellum?
pons, cerebellum, thalamus and back to cortex
