Motor and premotor Cortex Flashcards
what can the motor cortex be divided into?
primary motor cortex (M1)
Premotor cortex
supplementary area
True or false: there is more surface area of the motor cortex specific for fine motor movements
True, it is soma topically organized
what areas of the motor cortex would be larger?
Hands and face
what does the motor cortex encode?
movements not individual muscles
what is the main function of the primary motor cortex?
the execution of voluntary movement
is movement contralateral or ipsilateral to the motor cortex?
contralateral
what components of movement does the primary motor cortex encode?
force
direction
distance
speed
what is alien hand syndrome?
Involuntary, uncontrollable
movement of the upper extremity
what part of the brain is activated when you have alien hand syndrome?
contralateral primary motor cortex
what lobe is the premotor cortex in?
frontal lobe
what are the main functions of the premotor cortex?
motor planning
it selects the appropriate movements to perform
what part of the motor cortex are mirror neutrons in?
premotor cortex
how does the premotor cortex influence motor behaviour?
primarily via connections with the primary motor cortex
less commonly via axons projecting through the pyramidal tracts
what impairments may we se if there is a lesion to the premotor cortex?
speed and automaticity of reaching/grasping
sequential movements
gait and posture
what are the main functions of the supplementary motor area?
Programming complex sequences of
movements and coordinating bilateral movements
Selects movements based on previous experience
if you were learning how to play tennis and imagines yourself serving like Serena Williams, what part of the brain does this motor imagery?
supplementary motor area
what happens if there is a unilateral lesion of the SMA?
complete lack of contralateral movement and impaired ipsilateral movement
anti phase movement can be affected
what are anti phase movements?
Typing and playing the piano
tapping your head and rubbing your belly
where does intention of movement occur?
prefrontal cortex
where does motor planning occur?
premotor cortex
where does the execution of movement occur?
primary motor cortex
what is the somatotropin organization of the anterior horn of the spinal cord?
medial= proximal muscles
lateral= distal muscles
what is an interneuron/ local circuit neuron/
the “middle-man” that branches locally to innervate other neurons
are interneurons primarily inhibitory or excitatory?
inhibitory
do interneurons project ipsilaterally or contralaterally?
both!
what are the two types of interneurons?
long circuit
short circuit
what is the function of long circuit interneurons?
innervates proximal muscles for balance and postural control
what is the function of short circuit interneurons?
innervates distal muscles for fine motor control
how many levels do long circuit interneurons span?
multiple levels