Motor Cortex ☹️ Flashcards
What are the two important areas of the Motor cortex?
Area 4 (M1) and Area 6 (Penfield)
What does stimulation of M1 lead to?
Muscle twitches on the contralateral side
What is area 6 in charge of?
Complex movements
What are the two regions of area 6?
Lateral (premotor area) and medial (supplementary motor area)
What is the babinksi sign used to detect?
Corticospinal tract damage
Describe BA 6s role in movement planning
- PMA (pre motor area) neurons have a ready set go phase
- ready has baseline activity
- set fires the neuron
- go the PMA ceases firing once the action is complete
What do mirror neurons in BA6 do?
BA6 responds watching another monkey do something
Does the M1 have the highest or lowest threshold for eliciting movements?
Lowest
What is cortical layer 5 in M1?
The pathway by which LMNs are activates
What is Layer 5 full of?
Beta Cells
What are Betz cells?
Large pyramidal cells that project to pools of LMNs and excite them monosynaptically
Betz cells branch and excited what?
Local inhibitory interneurons which provides reciprocal inhibition
What are the two sources of input to Betz cells?
Cortical areas - BA 6, 3, 2, 1
Thalamus - VLc relays info from cerebellum
How do commands for precise movements reflect in UMN activity?
Burst of activity happen before and during a movement in the pyramidal cell which encodes both force and direction where certain cells respond more to a certain direction of movement more than others to get that fine tuned movement
What are movements of direction encoded by?
Collective activity of neurons aka population coding
