Fig. 6: OnOff circuits multiplex spectral and temporal information.

a Example spectral kernels for six of the twelve OnOff clusters as indicated. For each cluster, shadings indicate the parts of the kernels that were classed as either colour opponent (brown) or non-opponent (grey, Methods). The timepoint of each cluster’s onset is indicated by a short vertical line (kernel time: −1). b Mean ± SD ‘kernel-opponency over normalised time’ for all twelve OnOff clusters C_2–13, based on the temporal and opponency measures indicated in (a); see Methods for details. On average, OnOff cluster kernels tended to be colour opponent over long timescales (1, brown), but converged onto a non-opponent (−1, brown) period on short time-scales (i.e. closer in time to the spike event at kernel time 0). The time-normalisation was required in view of the very different overall kinetic regimes across clusters. c–f Mean On- (c, e) and Off- (d, f) step responses as indicated for the same OnOff clusters listed in (a), illustrating some of their diversity in kinetics and amplitudes. Note that for On-, but not Off-, red-responses tended to exhibit the largest amplitudes and shortest latencies. The summary plots in (e) and (f) show the mean ± SD response amplitudes and latencies of all CS and WS responses for all twelve OnOff clusters, each normalised to their respective red response. g, h Principal component analysis (PCA) of average On- (g) and Off- (h) WS and CS responses across all twelve OnOff clusters. Top: Traces going into the PCA, which comprised all CS responses except UV, which was generally weak, and 5 of the 10 WS responses (every second contrast value, i.e., 100, 80, 60% etc.). middle: First and second principal component, as indicated, and bottom: Peak-normalised loadings (Methods) of each step response onto the two components. Note that for On-, but not Off-, WS and CS step responses followed approximately orthogonal trajectories in this PC space (indicated by the shaded arrows). i, j (as g, h), but computed separately for the six OnOff clusters shown across (a, c, d). By and large, individual OnOff clusters behaved similarly to the population means (g, h). Source data are provided as a Source Data file.