Postural Control and Locomotion Flashcards
wheere are the motor neurons innervating axial and prozimal muscles located
meidal area of anterior horn
where are the motor neurons innervating distal muscles located
lateral area of anterior horn
what are ventromedial pathways invovled in
posture and locomotion of axial and proximal muscles
what is origin of lateral vestibulospinal tracts
vestibular nuclei
where do lateral vestibulospinal tract descend
all levels of spinal cord
what is the function of lateral vestibulospianl tracts
facilitate motor neurons of extensor muscles
affect posture
origin of medial bestibulospinal tract
bestibular nuclei
where do medial vestibulospinal tract descend
upper thoracic cord
function of medial vestibulospinal tract
mediation of reflex head movements in response to vestibular stimuli
adjust position of head
origin of pontine reitculospinal tract
pontine reticular formation
where does pontine reticulospinal tract descend
all levels of spinal cord
function of pontine reitculospinal tract
adjustment of posture and body balance
origin of medullar (lateral) reticulospinal tract
medullary reitcualar function
function of reticulopsinal system
modulate reflex action during movement
integrate vestibular and other sensory input with motor commands from cerebral cortex
origin of tectospinal tract (colliculospinal tract)
superior colliculus
where does tectospinal tract project
cervical spinal cord
function of tectospinal tract
coordinate head and eye movement
posture
overall position of body and limbs relative to each other and in space
postural stability
ability to control center of mass in relationship to base of support
what system senses body sway
vestibular
vection
perception of self-motion induced by visual stimuli
what is the position of head controleld by
neck muscles and neck proprioceptions
labyrinth righting reflex
head righting reflex that is driven by vestibular input
optical righting reflex
visual input that keeps head upright
where are asymmetrical tonic neck reflexes seen
birth - 6 mons
where is symmetrical tonic neck reflex seen
4/6mon - 12 mon
asymmetrical tonic neck reflex
if head is turned to one side, limbs on that side extend and limbs on other side flex
symmetrical tonic neck reflex
when next is extended the upper limbs extend and lower limbs flex
when do you see tonic neck reflexes
pt with vestibular damage
decrebrate posturing
everyting is extended
when do you see decrebrate posturing
lesions of upper pons
decoritcate posture
arms are flexed and legs are extended when pt is supine
whend o you see decorticate posture
lesion of IC, upper midbrain/diencephalon
where do humans have stepping pattern generators
inspinal cord
SPGs
networks of spinal interneurons that can elicit alteranting patterns of flexion and extension at hip and knee
how are SPGs activated
descending input
how are actions of both legs coordinated
commissural fibers
what is happening with cerebral palsy
too strong of a stretch reflex
what happens if you cut the dorsal root
decreased spasticity
do Ia fibers affect gamma motor enurons
no, only affect alpha
during voltunary action what are you normally stimulating
obth alpha dn gamma moter nruons
is stimulation of just gamma motor neurons enough to creat muscle tension
no
if gamma motor neurons are excited enough what will happen
they will cause contraction o fintrafusal fibers which stimulates the Ia afferent from the muscle spindle
What happens if Ia fibers fire enough
they will excite homonymous muscle’s alpha neurons and cause muscle to contract
