Lecture 13 - Voluntary Movement and the Primary motor cortex (2) Flashcards
What do Corticospinal neurons connect to in the spinal cord?
Alpha motor neurons
What results from successive cortical stimuli in spinal motor neurons?
Progressively larger excitatory potentials
Do corticospinal neurons make connections with interneruons in the spinal cord?
Yes
What is the role for corticospinal neurons making connections with interneurons?
- They project to alpha motor neurons
- Regulating large numbers of muscles
- Contribute to multi-jointed movements
How does motor neuron activity relate to the muscle force?
Individual neurons are tuned for DIRECTION and FORCE
What is the preparatory set?
The intent to perform a movement modifies the firing pattern of neurons in the primary motor cortex
What are interesting findings regarding the preparatory set and conscious perception?
- The preparatory set occurs ~500ms before movement
- Conscious perception occurs ~200ms before movement
- Your preparatory set decides to make the movement before you consciously decide to make the movement
Hows does the firing rate of Corticalmotor neurons differ?
- High tonic rate during dynamic phases of movement
- Lower tonic rate when steady force is needed
How are Corticalmotor cells identified?
Using spike triggered averaging
How is spike triggered activating performed?
- Record APs from Corticalmotor cells you are interested in
- Record EMG of the muscle you think your cell might be influencing
- Take EMG surrounding each spike
- Average all these EMG records
If the spike triggered averaging is flat what does that tell you?
There is no connection between the muscle movement and that Corticalmotor cell
What does a raster plot show you?
The activity of a neuron in time
What does each row correspond to in a raster plot?
A trial
What does each dot correspond to in a raster plot?
A spike observed during the trial
How do you reduce the misinformation provided by noise?
Use more than one motor neuron to give precise measurements
