convergence times

[Lyle J. Borg-Graham]

	might occur in 10 msec.  As long as there are no action potentials
	in the loop, iteration can go pretty fast (in neural terms).
	For several decades now Gordon Shepherd has been stressing the
	importance of computation in the dendritic net.


It seems pretty likely that intradendritic interactions (electrical or
chemical) are important; at least the biophysical substrate is rich
enough, and especially so after adding in the morphometrics. Finding
the smoking gun (as opposed to simulations which show plausibility) is
probably imminent. But iterations, strictly speaking, require a
discrete *loop*, and the speed of such a pathway is of course limited
by the slowest element in the chain, not by the fastest (e.g. some
500us *component* of a synaptic event). I think that iterative
mechanisms constitute one class of interactions, while (continous)
feedback (which can be very fast) mechanisms are another.