Figure 7.

Two different neural connection properties and their relation to synchrony and LTP are shown. (A) Two pyramidal neurons (P1 and P2) have excitatory projections to a down-stream neuron D. If these neurons fire in synchrony (as it happens at t1), their impact on the down-stream neuron adds up, thus increasing the likelihood of a discharge and LTP. If they fire asynchronously (t2 and t3) there is low probability that D will discharge and show LTP. (B) Neuron P1 has excitatory projections to the downstream neuron D, whereas neuron P2 has an indirect inhibitory projection to D, via an inhibitory interneuron I. In this case, synchronized firing (at t1) does not add up. Instead, only desynchronized firing (at t2) would lead to a depolarization of D, enhancing the likelihood of LTP. Figure inspired by Schneidman et al. (2011).