Figure 2. Excitatory and inhibitory presynaptic ensembles are co-tuned for orientation but not direction.

(a) Peak-normalised responses to drifting gratings of an example postsynaptic neuron. Scale bar: 5 s. (b) Tuning curves of the postsynaptic neuron in a (neuron i) and of a second postsynaptic neuron (neuron ii), after alignment of their preferred direction to 0 deg (mean ± s.e., N = 10 trials). Preferred directions for the two neurons were-30 deg and 180 deg. (c) Average tuning across the postsynaptic neurons responding to drifting gratings (mean ± s.e., N=16). (d) Normalised responses of 12 example excitatory presynaptic neurons traced from the first postsynaptic neuron in a. (e) Distribution of preferred direction from the excitatory presynaptic ensembles connected to the postsynaptic neurons in a, relative to the postsynaptic preferred direction. (f) Average distribution of preferred direction for excitatory presynaptic neurons pooled across all layers (N=15, median ± m.a.d.). *** p_kw=10^-8, one-way Kruskal-Wallis test across orientations; n.s: p_w=0.39, Willcoxon signed rank test between preferred and opposite direction. (g) Same as e, for presynaptic ensembles within L2/3 (top) and within L4 (bottom). (h) Same as f, for presynaptic ensembles within L2/3 (top, N = 15, p_kw = 10^-7, p_w = 0.49) and within L4 (bottom, N=13, p_kw= 2*10^-5, p_w= 0.59). (i) Same as d, for 12 example inhibitory presynaptic neurons. (j) Same as e, for the inhibitory presynaptic ensembles (p_kw = 0.38, p_w = 0.25). (k) Same as f, for the average distribution of preferred direction of presynaptic inhibitory neurons (N = 4).