Figure 3.

Example network and memory evaluation. (A) Two potential memory models derived from the sample biological network [75]. On the left, a UCS and R pairing that show no memory. The UCS (Mp) is stimulated (downregulated) during the grey training period and R (Mpp) is similarly downregulated. However, when the stimulation stops R reverts to its original behavior in the test period (green). On the right, the same network, but a different permutation of the UCS and R pairing which demonstrates memory. The UCS (Mpp) is stimulated (upregulated) and R (Mp) shows a response from its baseline behavior. However, when stimulation is halted (green test period), the behavior of R has continued to rise, rather than returning to baseline. Therefore, we conclude that this circuit shows a form of memory consistent with our functional definition—the behavior of R has been specifically modulated by past experience via stimulation of the UCS. (B) A cartoon representation of how potential memory models are evaluated using the example from (A). In this biological model, only two potential memory models passed the pretest and of those only one showed any memory (50%).