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Biological and Cognitive Foundations > Control of Movement > Flashcards

Flashcards in Control of Movement Deck (31):


contraction of muscle, bends joints



extension of muscle
straightens joints


extrafusal muscle fibers

served by axons of the alpha motor cortex
contraction of these provides motive force
served by a single myelinated axon of an alpha motor neuron


intrafusal muscle fibers

ensure your muscles are contracting so the brain doesn't exert as much energy
served by sensory axon and motor axon


motor unit

consists of an alpha motor neuron, an axon, and associated extrafusal muscle fibers


skeletal muscle

consists of a bundle of myofibrils
these consist of actin and myosin
myosin protrusions interact with actin filaments to contract muscle


neuromuscular junction

synapse between efferent neuron and membrane of muscle fiber
the terminal buttons synapse on motor endplates, located in the grooves along the muscle fibers


endplate potential

large and always causes a muscle to fire
when an axon fires, ACh is activated and makes depolorization of the postsynaptic membrane


How does myosin interact with actin to contract muscle?

when depolarization happens, voltage dependent calcium cannels open up, permitting only calcium to enter. this produces a contraction. the cell extracts energy from ATP in the cytoplasm and the myosin cross bridge "rows" the actin filaments down the strand of muscle.

blocking this channel would inhibit movement


golgi tendon organ


responds to increases in muscle tension

located in tendons at opposite ends of a muscle

act as "brake" against vigorous contraction; send impulse to interneurons in spinal cord to inhibit motor neurons 

(weight dropped in hand example)



muscle spindles

respond to muscle length (stretch)


neural circuit of monosynaptic stretch reflex

reflex in which muscle contracts in response to quick stretch


1 sensory neuron--synapse--1 motor neuron 

Important for postural control-standing upright 


gamma motor neurons

synapse with intrafusal muscle fibers and cause them to contract and adjust their sensitivity

2 types:
relaxed gamma motor neurons: make fibers insensitive to stretch 

active gamma motor neurons: make fibers MORE sensitive to stretch 


primary motor cortex (M1)

primary motor cortex (M1)
located near all executive functions
axons move from M1 to connect to spinal cord and control muscles
M1 controls contralateral side of the body
organized topographically (somatotopically)


lateral group 

a group of neurons that control movement
consist of corticospinal tract, corticobulbar tract, adn rubrospinal tract
involved in independent limb movements



ventromedial group

neurons that control movement 
consiste of vestibulospinal tract, tectospinal tract, reticulospinal tract, and ventral corticospinal tract
control automatic movements of the trunk 



supplementary motor area

involved in planning the elements yet to come in sequences of movements


pre-supplementary motor area (pre-SMA)

involved in control of spontaneous movements and perception of control


readiness potential

motor cortex activity occurring before any voluntary movement


premotor cortex

involved in learning and executing complex movements guided by sensory information
involved in using arbitrary stimuli to indicate what movement should be made


mirror neurons

located in premotor cortex 
reciprocally connected with neurons in the posterior parietal cortex
respond to eitehr the sight or execution of particular movements


parietal reach region

part of medial posterior parietal cortex
plays a role in pointing and reaching with hands


anterior parietal sulcus

control hand and finger movements involved in grasping 

part of dorsal stream



types of apraxia (4)

limb-moving wrong part of limb, incorrectly moving the correct part, or correct movement in the incorrect sequence
constructional-trouble drawing pictures or assembling objects or following a map
oral-problems moving muscles for speech
apraxic-problems writing


basal ganglia

responsible for initiating an action not guided by a stimulus 
contain caudate nucleus, putamen (both input nuclei), and the globus pallidus (output nuclei)
influence voluntary movement


subthalamic nucleus 

part of hyperdirect pathway and target of deep brain stimulation


indirect pathway (NO GO)

  1. M1 excites caudate/putamen
  2. caudate putamen inhibits (through GABA) the globus pallidus externa
  3. the globus pallidus externa inhibits the subthalamic nucleus
  4. the subthalamic nucleus excites the globus pallidus internal pathway
  5. the globus pallidus internal pathway inhibits the ventral anterior and ventrolateral nucleus of the thalamus
  6. the sum inhibits M1 (no movement)


direct pathway (GO pathway)

  1. M1 excites caudate and putamen
  2. caudate and putamen inhibit globus pallidus internal pathway through GABA
  3. the globus pallidus internal pathway inhibits the VA/VL thalamus
  4. the VA/VL thalamus excites the motor cortex (M1)


the hyperdirect pathway

 stops somethign that has already been set in motion with a much shorter delay than the indirect pathway

  1. M1 excites the subthalamic nucleus
  2. subthalamic nucleus excites the globus pallidus internal pathway
  3. the globus pallidus internal pathway inhibits the VA/VL thalamus
  4. the VA/VL thalamus excites M1



has twice as many neurons 
controls ipsilateral side
when damaged, neurons are erratic and uncoordinated
damage to lateral zone causes weakness and decomposition of movement and impares the timing of rapid ballistic movements



What are polysynaptic reflexes related to?  

Give an example

Related to inhibition

example: limb withdrawal in response to harmful stimulus