Cognitive/motor 3 Flashcards
what does motor control involve
many brain areas
what consciously initiates movement
higher centers - frontal portion of brain
motor cortex= sends axons down spinal cord
describe middle level
like basal nuclei
Executes individual muscle contractions
make corrections based on sensory info (takes into account feedback from sensory organs)
middle layer - thinks about all muscle contractions or relaxations
name and describe the 2 descending tracts
corticospinal - skilled movements, innervate hands and feet
extrapyramidal, trunk and posture - comes out of neurons from brainstem driven by middle layers, involved in automatic changes in trunk and posture we do not think about, like reach for coffee = automatically contract in muscles to compensate = mediated by extrapyramidal pathways
what are receptors
like muscle spindle and golgi tendon organ
what do voluntary movements have
involuntary component
describe voluntary control of movement
central sulcus
Consciously initiate movement –> premotor cortex –> starts planning of what has to happen for movements to occur –> primary motor cortex - neuron will activate and send axons down spinal cord (sits in front of somatosensory cortex)
Together = sensorimotor cortex (primary motor cortex)
describe organization of primary motor cortex
some areas in motor cortex takes up a lot more surface area
corresponds to parts of body with highly skilled movements and have many muscles to be controlled
describe somatotopic motor representation
1) Systematic relationship between select muscle groups and the body areas they control- body layed out in organized Fashion
2) Size of body structures in primary motor cortex is proportional to the number of neurons dedicated to their motor control.
3) Size of body structures in primary motor cortex is proportional to the degree of skill required to operate that area of the body.
Describe direct cortical control of movement - gen
2 major descending pathways
alpha gamma motor neuron’s send axons down from primary motor cortex
describe corticospinal pathway in detail
skilled movements
direct control
unqiue since directly activates motor neurons
crosses in medulla - contralateral control of body from motor cortex
directly innervates alpha and gamma motor neurons
describe extrapyramidal pathway in detail
trunk and posture
contract and relax trunk muscles, middle layers of motor cortex
interneurons and gray matter
indirect activation of alpha and gamma motor neuron’s since activate interneurons
describe corticospinal motor pathway - 5 statements
1) Originates in primary motor cortex (precentral gyrus). 2) Compact, discrete fiber tract direct to spinal cord.
3) Crossed: Controls contralateral muscles.
4) Extremities: Predominantly hands and feet.
5) Controls skilled voluntary movements.
describe extrapyramidal motor pathway - 5 statements
1) Originates from neurons in brainstem.
2) Diffused and indirect: Several descending tracts via the brainstem.
3) Crossed and uncrossed. - ips and contralateral control
4) Trunk and postural muscles.
5) Controls upright posture, balance, and walking
what is muscle tone
Resistance of skeletal muscle to stretch
