a, Example of a within-compartment bi-directional (WC-BD) cell. b, 70/116 (60%) showed within-compartmental bi-directionality. c, Size asymmetry of tuning curves in the WC-BD cells is compartment-specific. Direction 1 was defined as the direction of the biggest peak in the lemon compartment, and direction 2 the opposite. Overall, firing rates were similar in the two compartments (left), but the direction of the dominant peak reversed between compartments. d,e Analysis of spike count (d) revealed an increase in spiking for WC-BD cells (1557.49 +/-41.86) compared with the BC-BD cells (1058.93 +/- 128.75) and the HD cells (1041.26 +/- 117.65; one-way ANOVA, [F(2,209) = 5.00, p = 0.01]; * = p < 0.05). However, firing rate spread, measured as the standard deviation (SD) of firing rates (e) was not different between cell types, being 3.80 +/- 0.23 for HD cells, 4.90 +/- 0.49 for BC-BD cells and 4.41 +/- 0.33 for WC-BD cells [F(2,209) = 2.80, p = 0.07]. Solid lines show mean and s.e.m.