Fig. 1.

Number of neurons that exhibited generic memory signals (repeated vs. novel) in the hippocampus, amygdala, prefrontal cortex, and anterior cingulate. In each of the four regions, the total number of neurons exhibiting a generic memory signal exceeded the number expected by chance, using an alpha level of 0.05 (the dotted line) based on the total number of neurons recorded per region. For example, 38 neurons in the hippocampus exhibited a generic memory signal, which was significantly above the 19.9 expected by chance.