M1 / pre motor cortex Flashcards
where is M1 located
rostral to the central sulcus
where is the pre motor cortex located
rostral to M1
what occurs in the pre motor cortex
more motor plannign than actual descending control of muscles
what do layer 5 (betz cells) neurons do
send APs down the descending spinal tracts
what is the motor homunculus
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
what occurs during different stimulations of M1
50 ms pulse = twitch on EMG
500 ms pulse = more complex motor mvmts evoked
longer pulses = move complex mvmts emerge
when do M1 neurons turn on
before the movement actually happens
why is the motor and sensory homunculus being represented the same way important
highly benefical for movement
what are mirror neurons for
allow use to learn by observation
- can pre plan movements based on the movement of their body
how do mirror motor neurons work
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
which types of neurons are represented in the pre motor cortex
neurons associated with the intention to move or not
what are the 3 different roles of neural processes in M1
- fires while holding the intention to move
- fires in response to presenting target and “go” cues
- increasing firing rate as “go” cue approaches
what is the function of a neuron that fires while holding the intention to move
plan motor movement
what is the function of a neuron that fires in response to presenting target and “go” cues
integration with visual info
what is the function of a neuron that increases firing rate as “go” cue approaches
shows anticipation based on time
what are the 3 different functions of neural processes in the pre motor cortex
- no movement intended - receognise taret and then decrease in firing rate once intention is known
- fires while holding intention to move
- fires in response to anticipation of cue
where does motor planning occur
both sides
- even if we’re only planning on moving one side
where is the motor plan held
both sides
where does the execution of movement occur
only on intended side (contralateral to M1)
why is it important to plan motor movements on both sides
allows us to quickly switch motor plan to the other side if there is a perturbation on the original side
are specific MNs in M1 specific to certain directions of mvmt
yes - have a preferred direction
how do specific MNs in M1 respond to different directions of mvmt
opposite to preferred = silent
preferred direction = highest firing
away from preferred = lowest firing
(bell curve of firing rate on each side of preferred direction)
can the population of M1 MNs change
yes - evolves during more complex mvmts
does the population vector come before or after the mvmt vector
before - can predict mvmt based on population vector
