THRESHOLDS AND SUPEREXCITABILITY

[Peter Cariani]

Dear Lyle,
  Although Raymond cites a fairly large nmber of empirical observations in
many different types of systems, and the basic channel types participating
in these systems are pretty much ubiquitous, I am not about to claim that
a simple model accounts for the potentially very rich temporal dynamics of 
all neurons. Obviously there are many types of responses possible, but there 
seems to be a lack of functional models which utilize the temporal dynamics 
of single neurons (beyond synaptic delay & refractory period) to do 
information processing.
Can Raymond's threshold results be accounted for via current models? I
haven't seen any models where the afterpotentials have amplitudes
sufficient to reduce the effective threshold by 50-70%, and I have yet
to see this oscillatory behavior developed into a theory of coding
(by interspike interval), except in the Lettvin papers I cited.
    In defense of simple models, they are often useful in developing the
broader functional implications of a style of information processing. If
most neurons have (potentially) complex temporal characteristics, then
we'd better work on our coupled oscillator models and maybe some
adaptively tuned oscillator models if we are going to make any sense 
of it all.   

Peter Cariani