Figure 4

Gradual cooling induced a calcium surge in both the pretectum and hindbrain of exposed larvae. (A) Stimulus and imaging paradigm for calcium imaging experiments carried out in both the pretectum and hindbrain. (B) Median frame fluorescence for pretectal and hindbrain recordings; traces for individual recordings are shown in cyan and the mean values are shown in blue. The fluorescence trace for a single recording in the pretectum and hindbrain is shown in red, the convolved eye trace and convolved stimulus for the example recordings are also shown in gray. (C) Maximum intensity projections at different time points from the example recordings shown in red in (B). 1: before cooling, 2: during cooling to 11°C, 3: recovery 1:30 to 5:40 min after cooling ceased. Scale bars: 30 μm. (D) The onset of the calcium surge was calculated in stimulus-correlated (regressor score >0.5) pixels. This onset was defined as the first time point at which the fluorescence was >5 standard deviations above the baseline. (E) The time point at which correlated pixels reached their highest pixel intensity. A, anterior; P, posterior; L, left; R, right.