|
|
Mathematical Biology seminar
John Milton
University of Chicago
"Neural control at the edge of instability"
October 15
3:05pm in LCB 225
Neural motor control mechanisms are frequently tuned at the edge of
stability. Examples arise in the control of saccadic eye movements and
bimanual limb movements. However the advantages offered by this
control strategy, if any, are presently unclear. A recently emphasized
paradigm for the acquisition of motor skill is stick balancing at the
fingertip. Motion analysis in three dimensions demonstrates that the
fluctuations in the vertical displacement angle of a stick balanced at
the fingertip obey a power law characteristic of on-off
intermittency. The presence of on-off intermittency implies that the
control mechanism is tuned close to a stability boundary and that an
important control parameter is being stochastically or chaotically
forced across this boundary. Measurements of the development of
balancing skill together with considerations of stick balancing as a
survival time problem suggest that tuning neural control at the edge
of stability provides: 1) a mechanism so that corrective movements can
be made faster than the delay; and 2) a mechanism to minimize the need
for consciously directed control movements. These observations
strongly resonate with recent functional magnetic resonance imaging
studies of novice and professional golfers that indicate that the
"road to automatic" for motor skill acquisition involves a changes in
both the motor and consciousness/emotional control systems of the
brain.
For more information contact J. Keener, 1-6089
E-mail:
keener@math.utah.edu
|
|
