Fig. 2
Binocular selective neurons in the optic tectum and pretectum. a Two half-cylindrical arenas were used to present moving gratings. The binocular zone (nasal 36°) was blocked. b The stimulus protocol consisted of 7 × 7 binocular motion phases. A unique combination of stimuli (stationary: St, temporal-to-nasal: TN, upwards: Up, nasal-to-temporal: NT, downwards: Down, pitch up: PiUp, pitch down: PiDo) was shown to both eyes in each phase. For each stimulus combination, the summed activity (z-score) across motion-sensitive neurons is indicated in arbitrary units (a.u.). The red rectangle indicates the 5 × 5 stimulus phases further analyzed in panels d–g. Rp, Rr, Ry: binocular pitch, roll and yaw rotational stimulus phases. Tt, Tl: binocular thrust (forward/backward) and lift (up/down) translational stimulus phases (also see Fig. 4a). c Calcium responses of three example cells (median activity across three repetitions). The rectangular gray shades correspond to the 64 motion stimulus phases (Additional file 1: Figure S1E). d Calcium activity heat maps, classified binary response types and linear model fits of the cells from (c). e Binary response type analysis. The number of neurons (in pretectum and tectum, n = 8 animals, four composite brains, see “Materials and methods”) is plotted versus the ~ 34 million (225) theoretically possible binary response types. Green, monocular response types; magenta and gray, binocular-selective response types; light blue: indistinct binocular response types. The first 34 frequent response types are illustrated below. Yellow, responsive phases; blue, non-responsive phases. f The number of neurons for the frequent monocular response types (each line corresponds to one response type), g binocular-selective response types (active only during one binocular stimulus combination) and h monocular pitch-responding type (only active during the indicated monocular pitch phases) are indicated in green (monocular responsive), magenta (binocular selective), gray (stationary selective), and red (pitch responsive). LE/RE: left/right eye