M1 / pre motor cortex

Question 1

where is M1 located

Answer 1

rostral to the central sulcus

Question 2

where is the pre motor cortex located

Answer 2

rostral to M1

Question 3

what occurs in the pre motor cortex

Answer 3

more motor plannign than actual descending control of muscles

Question 4

what do layer 5 (betz cells) neurons do

Answer 4

send APs down the descending spinal tracts

Question 5

what is the motor homunculus

Answer 5

same representation as sensory homunculus
messy and overlapping
- communication between multiple body parts because nothing really moves fully in isolation
- gives us a rough estimate of the region of the body

Question 6

what occurs during different stimulations of M1

Answer 6

50 ms pulse = twitch on EMG
500 ms pulse = more complex motor mvmts evoked
longer pulses = move complex mvmts emerge

Question 7

when do M1 neurons turn on

Answer 7

before the movement actually happens

Question 8

why is the motor and sensory homunculus being represented the same way important

Answer 8

highly benefical for movement

Question 9

what are mirror neurons for

Answer 9

allow use to learn by observation
- can pre plan movements based on the movement of their body

Question 10

how do mirror motor neurons work

Answer 10

fire when watching a movement
- requires the person watchng to be able to do the movement with their own body for the neurons to fire
- pre plan movements based on the movement of the other’s body

Question 11

which types of neurons are represented in the pre motor cortex

Answer 11

neurons associated with the intention to move or not

Question 12

what are the 3 different roles of neural processes in M1

Answer 12

1. fires while holding the intention to move
2. fires in response to presenting target and “go” cues
3. increasing firing rate as “go” cue approaches

Question 13

what is the function of a neuron that fires while holding the intention to move

Answer 13

plan motor movement

Question 14

what is the function of a neuron that fires in response to presenting target and “go” cues

Answer 14

integration with visual info

Question 15

what is the function of a neuron that increases firing rate as “go” cue approaches

Answer 15

shows anticipation based on time

Question 16

what are the 3 different functions of neural processes in the pre motor cortex

Answer 16

1. no movement intended - receognise taret and then decrease in firing rate once intention is known
2. fires while holding intention to move
3. fires in response to anticipation of cue

Question 17

where does motor planning occur

Answer 17

both sides
- even if we’re only planning on moving one side

Question 18

where is the motor plan held

Answer 18

both sides

Question 19

where does the execution of movement occur

Answer 19

only on intended side (contralateral to M1)

Question 20

why is it important to plan motor movements on both sides

Answer 20

allows us to quickly switch motor plan to the other side if there is a perturbation on the original side

Question 21

are specific MNs in M1 specific to certain directions of mvmt

Answer 21

yes - have a preferred direction

Question 22

how do specific MNs in M1 respond to different directions of mvmt

Answer 22

opposite to preferred = silent
preferred direction = highest firing
away from preferred = lowest firing
(bell curve of firing rate on each side of preferred direction)

Question 23

can the population of M1 MNs change

Answer 23

yes - evolves during more complex mvmts

Question 24

does the population vector come before or after the mvmt vector

Answer 24

before - can predict mvmt based on population vector