Figure 4.

Theoretical interaction of temporal resolution and timescale characterizing the involvement of the hippocampus in memory for elapsed time. Each interval discrimination tested is plotted according to its corresponding temporal difference (y-axis) and timescale (x-axis). Areas of the graph thought to engage the hippocampus (high temporal resolution) or corticostriatal circuits (short timescales) are shaded in red and blue, respectively (purple shading denotes overlap). Our data suggest that the hippocampus is critical when the temporal resolution demand is high and the timescale is long (red quadrant, lower right). However, hippocampal involvement at short timescales is thought to interfere with the corticostriatal system; thus, inactivating the hippocampus leads to an improvement in performance (purple quadrant, lower left). Disrupting the hippocampus does not affect performance on discriminations involving large temporal differences at long timescales (white quadrant, top right).