l13 Flashcards
lower motor neuron location
ventral horn of spinal cord
(can be in cranial nerve too)
upper motor neuron
cortex, brainstem
lower motor neuron somatic musculature
axial: trunk
proximal: shoulder elbow, pelvis, knee
distal: hand feet digits
alpha lower motor neuron
force of contraction
small = fine dexterity
large = anti-gravity leg -> standing
alpha lower motor neuron receive input from
UMN
spinal interneuron
,..?
piezzo proprio muscle spindle func
detect stretch
group 1a func
transmit feedback (eg length of muscle) to ventral horn
gamma (lower) func
maintain tone in intrafusal when muscle relax
brain descend lateral pathway responsible for
voluntary, esp distal, under cortical control
brain descend ventromedial pathway responsible for
posture + locomotion, axial and proximal,
rubrospinal where, receive input where
red nucleus
receive M1
flexors upper limb
upper motor lesion
contralateral above medulla
ipsilateral below
Spastic paralysis
increase tone + reflex
fractionated movement
babinski
lower motor neuron
IPSILATERAL
flacid
decreasetecto
tectospinal tract
visual auditory
-> genereate motor to direct head eyes toward there
pontine medulla reticulospinal tract
antigravity (medial_
lateral (medullary) allow movement + inhibit lower limbs
vestibulo
medial (cervical, bilateral) head eyes stable
lateral lumbar, ipsilateral balance leg
vestibulocerebellum
??? balance, oculomotor control
spinocerebellum
motor control via somatopic mapping??
Connections of M1
- to brainstem, controlling ventromedial pathways.
- spinal cord.
- Thalamus (relaying cerebellar input).
Two Sources of Input to Betz Cells
- Cortical areas (area 6 and S1)
- Thalamus
Betz cells is?
Pyramidal cells in cortical layer 5
Secondary Motor Area – Area 6 pathway
- Lateral region → Premotor area (PMA)
Medial region → Supplementary motor area (SMA)
Secondary Motor Area – Area 6 receive input from
prefrontal and posterior parietal cortex
differences between PMA and SMA
t innervate different groups of muscles.
medial sma innervate what muscle
distal (directly)
lateral pma innervate what muscle
proximal via reticulospinal
Per Roland did what
voluntary/rehearsal of movemen
Evarts did what
recorded activity in the SMA of awake, behaving animals, showing an increase in activity 1 second before movement of either hand.
highest order posterior parietal cortex (area 5 + 7)
spatial perception
highest order: prefrontal cortex
Abstract thought, decision-making, consequences of action.
area 5 receive input from
3, 1, 2(S1)
area 7 receive input from
higher-order visual cortical areas
3 function division of cerebellum
Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum
3 lobes of cerebellum
anterior
posterior
floculonodular
2/3 zone
lateral
medial (vermis, intermediate)
3/4 nuclei
dentate
fastigital
interpose (emboliform, globose)
function cerebellum
- Independent, identical circuits repeated throughout.
- Coordination
- Motor timing
- Smooth moves
- Executive functions: verbal fluency, working memory, planning.
Personality: focus, attention, impulsivity.
Vestibulocerebellum where, function, pathway
- flocculonodular lobe
- function: balance, oculomotor
- somasen (neck), labyrinth, visual -> vestibular nuclei -> vestibular nuclei (brainstem)
Spinocerebellum where, function, pathway
- Vermis and intermediate zones
- motor control via somatotopic map
- 2
+ somasen (limb) -> spinocerebella, pontine nuclei -> ventralateral thalamus (to motor prefrontal, premotor, parietal) or red nucleus reticular nuclei (to interneuron in spinal cord, inferior olive, brainstem nuclei)
+ somasen(trunk) -> spinocerebella nuclei -> ventralateral thalamus (to motor prefrontal, premotor, parietal) OR vestibular nuclei (to motor and interneuron - spinal cord)
cerebrocecebellum
- Lateral hemispheres
-> pontine nuclei
1. ventralateral thalamus (to motor prefrontal, premotor, parietal)
2. to red nucleus reticular nuclei (to interneuron in spinal cord, inferior olive, brainstem nuclei)
