Motor Learning Flashcards
what is the flow of info in the cortical areas during motor function/reach planning?
Visual > parietal >( frontal > ) premotor > primary motor>muscles
what is intrinsic vs extrinsic?
Intrinsic – muscle, joint (jonit angle vector coordinates)
Extrinsic – position + direction (visual coordinate)
what experiment helped ID whether PPC/M1 were extrinsic or intrinsic?
reaction-time task: visual target presented (CUE) and reaching movement (GO)
PPC neurons encode target of intended movement even after the cue is not presented
M1 neurons change firing based on different forces (for the same target), while PPC neurons encode target location and not the forces necessary to reach that target.
(Strick Paper) How can you tell if a neuron is extrinsic from its firing pattern in the three hand on level position?
If neurons’s activity is the same in all 3 types of grabs (pronated, midposition, supinated), it is extrinsic (responds to DIRECTION of motion, not specific hand orientation).
note: monkey makes wrist movements using postures and directions allow dissociation of coordinate frames
same direction in space (up, down, left, right): extrinsic
different change in joint angle (flex/extend): intrinsic
(Strick paper) how can you tell if a neuron is intrinsic from its firing pattern in the three hand on lever position?
Look across all grab types. If the neuron’s firing rate changes from grab type to grab type, it is intrinsic.
(Strick paper) what kind of coordinate frame are in the PMv, M1 and muscles?
PMv: all extrinsic
M1: some intrinsic, some extrinsic
muscles: all intrinsic
check the slides for the graph
what is the evidence that the cerebellum is involved in motor learning
Throwing stuff at targets with/without prism goggles experiment
In normal brain, put on prisms > throw location is initially off > take off prisms > throw location is initially off (after-effect)
In patient w/ lesion, NO improvement in throw location with prisms on, NO after-effect -> no learning
describe the single-neuron motor learning experiment
Monkey w/ joystick (in a force field), with cursor, performing reaching tasks (center-out task)
No force-field -> reaching is straight
CCW force field/early force -> reaching curves bend CCW
Late Force -> go back to straight after training
Early washout (NO force field) -> after-effect (trajectories curve CW initially
Late washout -> go back to straight after training
what would the tuning curves for a kinematic neuron look like in the force field experiment
Kinematic = extrinsic
No change in tuning between baseline, force field, and washout
what would the tuning curves for a dynamic neuron look like in the force field experiment
Dynamic = intrinsic
Oriented one way for baseline and washout, a different way for force field
what would the tuning curves for a memory neuron look like in the force field experiment
Tuning changes from baseline to force field, but stays that way after washout
memory II: doesn’t change direction during force field, but in opposite direction during washout
what is the function of the posterior parietal cortex
Align proprioception of arm with vision of hand
Compute hand position in space
Compute target position in space
what is the function of the premotor cortex
Code the desired movement by “subtracting target position from hand position”
what is the function of M1
Transform the desired movement to muscle activity patterns and send this command to the spinal cord.
two questions asked in this lecture?
- how does brain control reaching?
2. how is sensorimotor learning implemented in the brain?
