Figure 2. Sustained firing patterns occur selectively in PRH cells.

(a–f) Firing-rate histograms (mean±s.e.m.) are synchronized on passing the PNR (left panels) and the PRM (right). Horizontal lines below the two curves of each graph indicate statistical significance of left (orange) and right (purple) trials relative to baseline (Wilcoxon signed-rank test, α=0.05; see Methods), or of the left–right difference (black, Mann–Whitney U-test with false discovery rate correction, α=0.05). (a) PRH cell increases firing rate throughout left but not right arm. Spike waveforms are shown on upper right (scale bar, 0.5 ms). (b) Another PRH neuron is bidirectionally modulated (left arm: decrement; right: increment). (c,d) CA1 (c) and S1BF (d) neurons fire transiently due to place field in left arm (c) and around PNR and return to middle lane (d). (e) Average NRD (preferred–non-preferred arm) for PRH (black), CA1 (green) and S1BF (blue). Horizontal lines below the two curves of each graph indicate statistical significance (Wilcoxon signed-rank test, α=0.01) of rate differences with colours corresponding to the three brain areas. (a–e) Each test bin needed to meet the α threshold against 2 s of contiguous baseline bins to be designated as significant (Methods). (f) Population overview of firing-rate differences for all three areas (cells ordered by moment of peak firing rate; cell counts on left).