TOWARD A BIOPHYSICALLY PLAUSIBLE BIDIRECTIONAL HEBBIAN RULE

Although the commonly used quadratic Hebbian-anti-Hebbian rules lead t o successful models of plasticity and learning, they are inconsistent with neurophysiology. Other rules, more physiologically plausible, fai l to specify the biological mechanism of bidirectionality and the biol ogical mechanism that prevents synapses from changing from excitatory to inhibitory, and vice versa. We developed a synaptic bidirectional H ebbian rule that does not suffer from these problems. This rule was co mpared with physiological homosynaptic conditions in the hippocampus, with the results indicating the consistency of this rule with long-ter m potentiation (LTP) and long-term depression (LTD) phenomenologies. T he phenomenologies considered included the reversible dynamics of LTP and LTD and the effects of N-methyl-D-aspartate blockers and phosphata se inhibitors.