Kinesiology 1080A/B Lecture Notes - Lecture 5: Thalidomide, Morning Sickness, Lesion
16 Oct 2018
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Electrodes in Monkey Primary Motor Cortex -Measuring Individual Neuron Activity:
- different colours and sizes
- colour represents what area of the body a particular neuron innervated
- size depicts how much activity was used
- yellow= thumb, blue= ring finger
- different neurons representing parts of the hand are intermingled
o not a very strict homoncular representation in primary motor cortex
o no absolute homoncular representation. - relative representation
o M1 not necessarily final common pathway for motor production
Monkey and raster plot:
- robotic arm placed at centre position
- around centre dot, there are 8 targets
- 1 target comes on and monkey must move to the target
- lines represent monkey trajectory to different targets
- measure single neurons in primary motor cortex
- raster plot: represents the firing frequency of 1 neuron
o 5 rows →each represents an individual trial
o each tick= depolarization (neuron firing)
- 0msec is the time at which a target was presented
- when the monkey moved to the 180 degree target, activity for raster plot
represents →more activity left than right
- decrease in activity when monkey is moving 45 degrees different
- show that M1 neurons can code for the directional tuning
o proves M1 is not the final common pathway to action
Parietal Motor cortex:
- functional motor movements→reaching and grabbing tasks
- Tetraplegic drinks beer with computer and probes to the parietal motor cortex
Monkey and Spinal Lesion:→video
- How brain decodes and processes information → New brain-spine interface
Prolonged M1 Electrical Stimulation:
- Longer burst electrical stimulation
- Penfield put probe on primary motor cortex for
longer and observed what happened
- Monkeys began to perform functional
movements
- (A)→ each starting position represents starting
point of limb. Probe M1 and monkey would
always move limb to its mouth
- motor commands for sophisticated movements
are stored in M1
o therefore, it is more than just a final
common pathway to action
Document Summary
Relative representation: m1 not necessarily final common pathway for motor production. Monkey and raster plot: robotic arm placed at centre position around centre dot, there are 8 targets. 1 target comes on and monkey must move to the target lines represent monkey trajectory to different targets. Measure single neurons in primary motor cortex raster plot: represents the firing frequency of 1 neuron: 5 rows each represents an individual trial, each tick= depolarization (neuron firing) 0msec is the time at which a target was presented. Parietal motor cortex: functional motor movements reaching and grabbing tasks. Tetraplegic drinks beer with computer and probes to the parietal motor cortex. How brain decodes and processes information new brain-spine interface. Penfield put probe on primary motor cortex for longer and observed what happened. Monkeys began to perform functional movements (a) each starting position represents starting point of limb. Probe m1 and monkey would always move limb to its mouth.
