Motor Systems Flashcards
regions important for motor system
SMA, primary motor cortex, ACC, basal ganglia, cerebellum, inferior frontal cortex, frontal eye field, premotor cortex, primary sensory cortex, parietal cortex
difference in function between cortical and subcortical system
cortical –> voluntary selection, planning and guidance of goal directed movements, also learning movement sequences
subcortical –> involuntary/automatic movements, modulation of movement, learning and optimization
function and organization of lateral tract
fine motor control (arms, legs, figners)
fully crosses in medulla to other side of body—> where we get contralateral control
function and organization of medial tract
bilateral control of posture, walking, bending, turning (trunk and head)
both crossed and uncrossed tubers, ipsilateral and contralateral components (trying to control at midline, must control both sides at same time to maintain posture)
what are the two ways to think about neuron function in the primary motor cortex
- as individual neurones which encode for specific muscles, drection of movement, force and speed. each individual neurone has a preferred direction force and speed
- population of neurons that code for action or sequences of action that require multiple muscles and have a goal
ex. if stimulate monkey brain –> can induce pre programmed movements such as climbing, reaching)
what happens when motor cortex is damaged
loss of voluntary movement (usually on opposite side of lesion), weakness/stiffness, aphasia
functions of SMA
receives input from parietal and frontal lobes, encodes movement sequences and timing and transmits motor programs to other parts of the body
function of PMC (premotor cortex)
receives input from parietal and frontal lobes and encodes relationship between effector and object, selection of appropriate motor plans
relays information to the SMA and motor cortex
functions of pre-SMA
gets first input from frontal cortex (top level of motor plannig), important for deciding which action to take
findings from single cell recording in monkeys about patterns and SMA
SMA encodes order of the sequence, first action of a sequence
pre SMA encordes position of a movement in a sequences, not matter the action
function of dorsal region in the motor cortex
sensory to motor (what object – what action)
coding what type of action should be selected based on sensory info
function of ventral region of premotor cortex
altering motor movements, specific motor commands for specific object characteristics (this is a small object, how do I adjust to grab it)
describe methods and results of piano training study
let people take little piano home for 6 weeks and learn to play
brain activity wile listening to tunes they learnt to play –> greater active in dPMC, parietal cortex and SMA
hearing melody activate motor plan learned
activity in auditory cortex when listening to melodies = predictive of amount of learning
what is coarticulation
one movements starts before the other is finishes, important for most skilled movement including speech, sports, music
motor plan
brain representation for the movement/set of movements to be made and the prediction of what should follows said movements
regions involved in making a motor plan
SMC (supplementary motor cortex) –> comes up with plan at abstract levle
premotor area –> codes for types of action tho must occur to meet plan
primary motor region –> executes motor plan
which region do mirror neurons occupy
ventral most regions of the ventral premotor cortex (overlapping with brocas areas)
what are mirror neurons
neurone that fire when watching someone else do an action that you have done (first found in monkeys)
maybe be important do encoding goals and intention
activity related to how close and action is to something you could do
way of encoding info form other non human creature
initial study of mirror neurons
reach and grasp study in money, noticed premotor cortex neurons were firing in monkey brain when watching the researcher reach and grasp for a reward (raisin) used for the monkey
mirror neurons in humans function
possibly important in learning language (think of babies imitating adults )
may help in decoding other people movements and how we should react
may be dysfunctional in autism (why they struggle to understand facial expression)
explain study of gripping cups and mirror neurones relation to goals and intention
two contexts (before tea and after tea) had people view action of pick up cup with knowledge of contexts, or view actions without context
,pre activity in mirror neurons when knowing context
is there activity in mirror neurons when watching animals make unfamiliar action (such as barking)
NO, mirror neurons only active for actions we ourselves can do
study : ballet dancer and capoera dancers watching videos of both dance styles
when watching their own style –> greater activiety in ventral premotor cortex and dorsal premotor cortex (important for decoding movement), the parietal cortex (transforms visual info into an action from ones own perspective) and superior temporal sulcus ( becomes active when seeing movement that looks biologically human)
study : ballet dancer and capoera dancers watching videos of both dance styles
when watching their own style –> greater activiety in ventral premotor cortex and dorsal premotor cortex (important for decoding movement), the parietal cortex (transforms visual info into an action from ones own perspective) and superior temporal sulcus ( becomes active when seeing movement that looks biologically human)
function of the ACC
monitoring, response section, inhibition and correction systems
more important for novel actions and replacing usual action with novel action if the time calls for it
evaluates outcome of action and checks for error s (compares desired outcome with action you made)
connections of regions in the ACC
posterior region connect / coactivate with the primary motor cortex (saccade, tongue, hand and foot regions)
middle region connect with SMA –> control of more complex sequences ((saccade, tongue, hand and foot regions)
anterior region connected with frontal lobe to control taks requiring more switching and conflict , hand and foot regions)
function of parietal cortex
integrating action with our physical world
integrating sensory system information to frontal motor regions
function of superior parietal lobule (dorsal stream)
where pathway
transform external space to body space
damage –> problems reaching, gripping, locating object in space
function of inferior parietal lobule (ventral stream)
what stream
sensory motor transformation for complex learned action and specific characteristic for specific action (using bottle opener, lighting a match)
create mental model of movements (allows for adjustments, predicts how movements need to be adjusted to be achieved)
damage –> problems interacting with objects, can pretend to do an action (pantomime)
main 3 function of the cerebellum
coordination
learning of motor skills
forward models (correcting errors as well)
also enhancing function of frontal lobe
what is a forward model
specific version of a model for a motor plan (allows for production of action to be compared to prediction)
once a forward model is built –> don’t see much damaged to them in cerebellar damage
true or false : cerebellum has more neurons compared to rest of brain
true
organization of cerebellum
modulates ipsilateral muscles
more medial areas –> body center
more lateral areas –> limbs
when does cerebellum reach peak development
adolescents
true or false : cerebellum is one of the most evolved regions between primates to us
true
Vestibulocerebellum (Medial regions) connection and results from damage
connection to brain stem, receives input from brainstem and projects back to cerebellum
damage –> impaired balance and walking
Spinocerebellum (Anterior regions) connection and results from damage
receives somatosensory and kinesthetic info from spinal cord and projects back to spinal cord, involved in movement of more medial movement (coordinating trunk and leg muscles)
damage impairs walking, smooth movement and eye tracking
Cerebrocerebellum (Lateral regions) connection and results from damage
receives input from temporal lobe, parietal lobe. Involved in regulation of highly skilled movement and learning
damage –> Impaired skill movement, learning, language (such as verb generation), executive function
does cerebellar damage completely abolish movement?
No, but it dysregulates it, people with damage can adjust there movements, but not readjust after (treadmill effect)
Darts study on cerebellar damage
2 groups, cerebellar damage and control
had to wear prism glasses which shift environment when throwing darts
control group was able to adjust once prims glasses were on, and then overshoot when glasses are off, but re adjust to get back to baseline throwing rate
damaged group was unable to compensate for prims shift, and no evidence of overshooting (which may be evidence of no adjustment or learning)
ataxia (form of cerebellum damage)
poorly coordinated movement (think nose test), plan for movement disturbed and poorly timed
intention tremors as well –> shaking of lips when performing goal-direction action often overshoots
dysarthria (form of cerebellum damage)
slow, slurred speech, impaired ability to control volume or pitch
decomposition of movement (form of cerebellum damage)
cannot control, coordinate multiple joints
difference between basal ganglia and cerebellum
Basal ganglia –> important for movement that may take time to initiate or stop
cerebellum –> movements that are not modified once they’ve been initiated
basal ganglia function
The basal ganglia manage the signals your brain sends that help you move your muscles. important for initiating action
basal ganglia function
preparing nervous system for voluntary acts, autopilot for when knows sequential movements, timing and switching between motor acts
helps with planning and learning for motor acts with motivational( reward )significance
basal gAnglia organization
organized in a series of separable loops with cortical regions
theory of how the basal ganglia loops work together
basal ganglia facilitates the cortical activity important for the selection of series of appropriate movement and inhibition of inappropriate ones
two routs in which information passes through basal ganglia
direct route –> sustaining or facilitating ongoing action
indirect route –> suppressing unwanted movement
symptoms of Parkinson’s
akinesia (inability to ignition spontaneous movements/bradykinesia (slowness of movement, tremors, cogwheel rigidity, disturbances of posture
what is thought to cause Parkinson’s symptoms
direct pathway is compromised because putamen not receiving adeuqete input
substantia nigra also dies during Parkinson’s leading to little input to direct pathway –> leads to overactive indirect pathway –> too much activity in globus pallideus, inhibits thalamus resulting in decreased motor activity
what is though to cause Parkinson’s
mix of genetic and environmental factors
