Motor control
Last week
This week, we will look at...
Muscles are activated by alpha motor neurons
The stretch reflex reveals some elementary processing in the spinal cord
Cortical anatomy of the motor system: lateral view
Medial view
PPT Slide
Basic questions regarding motor control can nowadays be answered
How to be precise with noisy components
Population coding
Coarse coding
Why coarse coding works
In primates abundant evidence exists for coarse coding
Georgopoulos shows that movement is coded in population vectors
Population vectors give accurate movement direction signals
Motor cortex sets up the signal, but execution is dependent upon other areas
Original plans in motor cortex are sometimes revised `on the go'
Activation of motor areas is a cascade rather than a sequence
Simple movement activations motor cortex and somatosensory cortex
More complicated sequences involve other areas
Imagined movements remain limited to the supplementary motor area (SMA)
Internally and externally generated movements
Skilled (Old) versus new motor movements
Response competition
`Elastic constraints' in motor development
Spinal cord
Coarse maps of limb movements in the frog
Cats with severed spinal cord could still walk on a treadmill
Method followed by Emilio Bizzi
Limb movements in frog spinal cord are coded with respect to their end-positions
The interactions of force fields can be described by vector calculus
Cerebellum
Glickstein: it is not `completely' clear what the cerebellum does
Global anatomy of cerebellum
More detailed anatomy of cerebellum
Louis Bolk: midline cerebellar vernis controls bilaterally synchronized movements; cerebellar hemispheres control unilateral movements
David Marr (1969): cerebellum is excellent for simple associative learning (conditioning)
`Correspondence views' on brain structures
Computational views on cerebellum
Basal ganglia
Summary of the architecture of the motor system
How these structures may contribute to our actions
Summary
Summary (continued)
Next week...
Email: jaap@murre.com
Home Page: http://www.neuromod.org/courses/public.html
Other information: neuroMod: Home of the Neural and Cognitive Modeling Group at the University of Amsterdam.
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