Fig. 2

Regression-based identification of gaze-tuned neuronal populations. a Schematic of the experimental setup and regression analysis. Volumetric recordings on GCaMP6f-expressing larvae were performed using one-photon light-sheet imaging (20 sections per stack, 1 stack per second) while monitoring saccadic dynamics. Voxel-by-voxel regression with the eye orientation signals were used to produce position-tuned and velocity-tuned 3D maps. Notice that the two maps overlap in a small subset of voxels (the two 3D maps are displayed separately in Supplementary Movie 3). b, c Dorso-ventral projection view and sagittal sections along two planes of the 3D functional map (mean over 7 fish) showing neuronal populations whose activity is tuned to the gaze orientation (blue and red) and to the gaze angular velocity (green and yellow). The voxel colour encodes the Z-score values obtained through multilinear regression (Supplementary Methods). Te, telencephalon; OT, optic tectum; Cb, cerebellum; Hb, hindbrain; RH, rhombomere. The grey dotted rectangle indicates the effective recorded volume. d Coronal sections along the dotted lines shown in (c) for one sample of the four regions delineated in (b). Region 1 encompasses the saccade generator burst neurons (SGBN); region 2 is the velocity-position neural integrator (VPNI); region 3 and 4 constitute the newly identified gaze-tuned rostral hindbrain population. It consists of four bilaterally symmetric clusters tuned to the ipsiversive gaze orientation (region 3) and 2 more rostral clusters tuned to the contraversive gaze angle (region 4). e Example ?F/F time-traces for these four regions. The red and yellow (respectively blue and green) traces correspond to the sub-populations tuned to leftward (respectively rightward) gaze orientation. The grey lines are the gaze angle traces (?? _gaze: solid line, ? _gaze: dashed line). f Corresponding mean peri-saccade ?F/F signals, computed over the leftward (red) and rightward (blue) saccades. Grey lines are peri-saccadic signals for individual saccades