Cognitive/motor 3 Flashcards

1
Q

what does motor control involve

A

many brain areas

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2
Q

what consciously initiates movement

A

higher centers - frontal portion of brain
motor cortex= sends axons down spinal cord

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3
Q

describe middle level

A

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

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4
Q

name and describe the 2 descending tracts

A

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

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5
Q

what are receptors

A

like muscle spindle and golgi tendon organ

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6
Q

what do voluntary movements have

A

involuntary component

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7
Q

describe voluntary control of movement

A

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)

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8
Q

describe organization of primary motor cortex

A

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

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9
Q

describe somatotopic motor representation

A

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.

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10
Q

Describe direct cortical control of movement - gen

A

2 major descending pathways
alpha gamma motor neuron’s send axons down from primary motor cortex

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11
Q

describe corticospinal pathway in detail

A

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

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12
Q

describe extrapyramidal pathway in detail

A

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

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13
Q

describe corticospinal motor pathway - 5 statements

A

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.

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14
Q

describe extrapyramidal motor pathway - 5 statements

A

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

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15
Q

what is muscle tone

A

Resistance of skeletal muscle to stretch

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16
Q

describe muscle tone of normal subject

A

slight and uniform

17
Q

how can muscle tone be damaged

A

damage to descending pathways
damage to motor neurons

18
Q

describe damage to descending pathways - muscle tone

A

mostly extrapyramdial and some corticospinal - mainly inhibitory
could be due to spinal injury overactive

hypertonia = abnormally high muscle tone
spasticity = overactive motor reflexes (how to know if patient unconscious)
rigidity = constant muscle contraction

19
Q

describe damage to motor neurons - muscle tone

A

hypotonia - abnormally low
muscle tone
Atrophy = loss of muscle masss
Decreased or missing reflexes
(Diseases that affect muscles themselves or neuromuscular junction)

20
Q

describe basal nuclei - ganglia

A

helps determine specific sequence of movements needed to accomplish desired action
collection of cell bodies
do not notice you have a basal nuclei till things go wrong

21
Q

name 2 basal nuclei moment disorders

A

parkinsons
huntingtons

22
Q

describe parkinsons disease - gen

A

common in elderly
one of most common movement disorders
reduced dopamine input to basal nuclei

23
Q

describe parkinsons disease -symptoms

A

akinesia = reduced movements
bradykinesia = slow movements
Muscular rigidity
resting tremor - when at rest

24
Q

describe parkinsons disease - treatment

A

treatment = increase dopamine concentrations in brain
some promise from deep brain stimulation

25
describe huntingtons disease - gen
genetic mutation that causes widespread loss of neurons in the brain shows up later in life neurons in basal nuclei are preferentially lost
26
describe huntingtons disease -symptoms
Hyperkinetic disorder = excessive motor movements choreiform movements = jerky random involuntary movements of limbs and face
27
describe cerebellum
Movement, timing, planning and error correction learning new motor skills recieves sensory info - vestibular, visual, auditory, somatosensory, proprioceptive contains almost half of brains neurons activates extrapyramidal descending pathway keeps things moving smoothly during execution of movement
28
describe cerebellar deficits - asynergia
smooth movements are subdivided into their separate components like stop motion doing things step by step usually cerebellum does it for you
29
describe cerebellar deficits - dysmetria
unable to target movements correctly "past pointing"
30
describe cerebellar deficits - ataxia
incoordination of muscle groups awkward gate
31
describe cerebellar deficits - intention tremor
during voluntary movements as motor command happening
32
describe cerebellar deficits - paralysis
no paralysis or weakness generally function ok but do not have highly skilled motor control