Fig. 6.

Firing patterns of lamina I neurons expressing non-Hebbian LTP. (A) Neurons expressing synaptic LTP after a conditioning stimulus exhibited either the gap or the initial burst firing pattern, whereas neurons showing no potentiation fired mostly in the gap firing pattern, or rarely in tonic, initial burst, or single spike pattern. The gap firing pattern was the most common firing pattern in all of the groups. (B) Typical example of initial burst firing pattern showing 2 or more bursts of action potentials at the beginning of the positive current injection. (C) Representative example of gap firing pattern with the characteristic long first interspike interval. Bottom traces show depolarizing current injections superimposed.