In December 2000 there was some discussion in this newsgroup of my
hypothesis that mitochondria might act as flip-flop memory elements in
neurons.
One counter-argument ran as follows: "Why should neurons need a flip-flop
memory element? There's no evidence they're digital".
Well, perhaps there is some evidence now. In the 21 December 2000 issue of
"Science" Dong-Sheng Wei et al report binary behaviour of some terminal
apical dendrites of pyramidal neurons, which they characterised as
"all-or-none responses that were subthreshold for somatic action
potentials".
They remarked that "Compartmentalized and binary behavior of
parallel-connected terminal dendrites can greatly expand the computational
power of a single neuron".
Of course I am aware that the paper in "Science" does not support my
hypothesis about a possible role of mitochondria, which is speculative.
However, it does (in my inexpert opinion) show that the behaviour of some
dendrites is "digital".
Andrew Gyles
