Figure 7.

Responses to full and half herringbone patterns. Shown are data for three example V2 neurons (shown in Fig. 3) to full herringbone patterns (as in Fig. 1G) and the two half herringbone patterns (contrast-modulated gratings, as in Fig. 1E,F). For each neuron, we show the measured grating tuning (column 1), the linear response prediction (column 2), tuning for carrier-exchange controls (column 3), and the full herringbone patterns (column 4, see stimulus icon). We also show tuning for each half pattern (half 1 and half 2, columns 5 and 6; see stimulus icons above). A, Responses of a first-order neuron. Tuning for full herringbone patterns was four-lobed; tuning for each half pattern was two-lobed and aligned with the linear prediction, reflecting the response to each carrier pattern present. B, Responses of a modulated by motion neuron. Full herringbone tuning was directional, with only two of the four tuning lobes evident; tuning for each half pattern was also directional, with only one lobe present, reflecting the response to each carrier. C, Responses of a second-order cue-orthogonal neuron. Full herringbone tuning did not match the four-lobed linear prediction; tuning for each half pattern was also identical in shape, indicating that it was cue-orthogonal for both stimulus types. D, Distribution of relative log likelihoods for V2 neurons tested with full herringbone patterns (N = 25). E, Comparison distribution for the same V2 neurons when tested with half herringbone patterns. We computed likelihoods from the responses to each half separately and plotted the average normalized likelihood for both halves. The distribution was qualitatively similar, with most neurons classified as first order, and a few as “second-order cue-orthogonal.”