From behavior to circuit modeling of light-seeking navigation in zebrafish larvae

Abstract

Bridging brain-scale circuit dynamics and organism-scale behavior is a central challenge in neuroscience. It requires the concurrent development of minimal behavioral and neural circuit models that can quantitatively capture basic sensorimotor operations. Here, we focus on light-seeking navigation in zebrafish larvae. Using a virtual reality assay, we first characterize how motor and visual stimulation sequences govern the selection of discrete swim-bout events that subserve the fish navigation in the presence of a distant light source. These mechanisms are combined into a comprehensive Markov-chain model of navigation that quantitatively predicts the stationary distribution of the fish’s body orientation under any given illumination profile. We then map this behavioral description onto a neuronal model of the ARTR, a small neural circuit involved in the orientation-selection of swim bouts. We demonstrate that this visually-biased decision-making circuit can capture the statistics of both spontaneous and contrast-driven navigation.

PiVR: an affordable and versatile closed-loop platform to study unrestrained sensorimotor behavior

“…Instead, we found that zebrafish larvae did modulate their turn angle as a function of the absolute light intensity ( Figure 4G). Consistent with the results of a recent study (47), we found that the turn angle tended to increase after down-gradient scoots ( Figure 4H). This observation is reminiscent of the increase in turn angle after leaving a virtual circle (43).…”

“…We show that zebrafish achieve positive phototaxis by increasing the amplitude of their turns when they are moving down-gradient and experiencing low light intensities. This new aspect of the sensorimotor strategy controlling zebrafish phototaxis has also been reported in an independent, recent study featuring closedloop light stimulations in a virtual-reality paradigm (47).…”

“…We presented zebrafish larvae with a virtual white light gradient. As in the work of Chen and In a real white light gradient, fish turn towards the light source by comparing changes in light intensity experienced between their two eyes (42,47). Due to the homogenous stimulation illumination in our experiments, fish could not use this strategy.…”

Algorithms underlying flexible phototaxis in larval zebrafish

“…However, a comparison of the swimming statistics during the preadaptation period ( Figure 1C-D) and the test period ( Figure 1E-F) revealed that fish do not simply perform positive phototaxis, as has been suggested by previous studies [10,11,13,14] , but that they consistently turn towards the side closest in luminance to the preadaptation period. This indicates that larval zebrafish prefer a luminance similar to the preadaptation luminance, suggesting that this value serves as a set point for subsequent luminance-driven navigation.…”

“…In this study, we establish luminance-based navigation in larval zebrafish as a model for investigating behavioral allostatic control. Previous work on luminance-based navigation in larval zebrafish has focused on their tendency to orient and swim towards brighter regions of luminance gradients; this behavior is termed positive phototaxis [10][11][12][13][14][15] . However, in naturalistic environments, luminance varies widely, both throughout the day and as fish move into and out of shade.…”