After 1st Midterm- descending control

Question 1

what does the premotor and primary motor cortex do

Whats are BETZ cells

Answer 1

pre motor plans movements and the primary executes the movement

send action potential down spinal tract

Question 2

Homunculus

is there overlap between what neurons attach where

Answer 2

on brain, parts of the body are correlate to parts on each.
hemisphere is toes, down is face

SO, the map is
messy and has substantial overlap in neurons

Question 3

M1 directionality

Answer 3

certain neurons in M1, fire more action potentials in one direction of movement

silent in the opposite direction

different neurons in M1 population have different preferred directions

Question 3

spread out M1 graph

Answer 3

each line is an M1 neuron, its orientation shows its preferred direction.
the red shows population vector and length of line shows firing rate

opposite direction is silent to a strong one

Question 3

Primary motor cortex
M1

delivering pulses to M1 and increase in pulse

how many muscles does it activate and dos it make complex movements

Answer 3

Deliver a 50 ms pulse and get a twitch in the EMG, deliver current for 500 ms or more and complex movement patterns emerge….

longer pulse, more complex movements

M1 is complex though, so stimulating it activates many muscles

Question 4

movement and population vectors during a complex movement

Answer 4

M1 creates movement so population vector spikes before movement then sends it out

the movement vector happens after population, and can be predicted by population

Question 5

sensory cortex other name

2 nuclei

Answer 5

S1- process sensory info from GTO, cutaneous, spindles, nociceptors

relay sensory info
VPLn and VPMn, below the neck is VPLn, above the neck is VPMn