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. Author manuscript; available in PMC: 2023 Jan 10.
Published in final edited form as: Curr Biol. 2021 Nov 24;32(1):176–189.e5. doi: 10.1016/j.cub.2021.11.007

Figure 2. Functional imaging of primary sensory neurons in the PLLg during head-restrained swimming.

Figure 2.

(A) Experimental setup. Calcium-dependent fluorescence signals are recorded using 2-photon microscopy and tail position is recorded simultaneously. Visual stimuli are projected under the animal, taps arise from a solenoid, and flow is delivered by pressure injection through a micropipette. (B) Example traces of top: fluorescence activity (ΔF/F) of flow-responsive neurons in the PLLg of a single GCaMP6s fish (light blue), and bottom: the animal’s concomitant cumulative tail curvature. Stars: swim bouts.(C) Average single-cell responses to 3.3 s of water flow delivery separated into instances that did and did not elicit motor responses. (Flow: n= 20, 26, 16, 24, 30 cells in 5 fish, Flow + motor: n= 18, 15, 16, 23, 15 cells of the same fish). Dotted line: flow onset. Since stimulus strength was calibrated to trigger behavior stochastically, some neurons were only imaged during flow delivery instances that did not elicit swimming, hence the discrepancy in cell number within individual fish across conditions. (D) Population average of stimulus-triggered neuronal activity in the PLLg (mean ΔF/F ± s.e.m.) in response to water flow that elicited (f+m, blue) and did not elicit (f, gray) motor responses (n= 5 fish). Averages arise from the single-cell measurements in Figure 2C. While the flow delivery period lasted 3.3 s, it is possible that a residual stimulus persisted after delivery was terminated. Bottom: swim probability during the same time period. (E) Example traces of top: fluorescence activity (ΔF/F) of 5 neurons in the PLLg of a single fish expressing GCaMP6s. A black and white grating was projected either statically or moving caudo-rostrally with respect to the fish at alternating 20 s intervals to promote swimming. Bottom: concomitant cumulative tail curvature. (F) Average single-cell responses (ΔF/F) during swim bouts in 11 fish (n= 22, 16, 19, 13, 17, 23, 27, 25, 22, 26, 23 cells). Dotted line: swim starts. (G) Population swim-triggered averages of neuronal activity in the PLLg (mean ΔF/F ± s.e.m.). Bottom: swim probability during the same period. Averages arise from the single-cell measurements in Figure 2F. See also Figure S2.