FIGURE 2.

Stimuli and neural circuits involved in social behaviors. (A,B) Left: Several types of stimuli were presented to the visual field of zebrafish using a virtual reality assay. Black dots vary in angular size, vertical dimension, horizontal dimension, and number. At 7 dpf, these stimuli elicited an aversive turn with an increasing probability of repulsion with an increase in the retina occupancy. At 21 dpf, stimuli of the same size were considered attractive. Right: the model proposed by Harpaz et al. (2021) hypothesized the existence of two different populations in downstream areas that are responsible for attraction or avoidance of social stimuli. While only the repulsive population is mature at 7 dpf, the balance of excitation and inhibition of the two populations determines the behavior of the fish at 14–21 dpf. (C) Left: black dots with bout-like motion elicited shoaling behavior in juvenile zebrafish, while continuously moving dots were considered not attractive (Larsch and Baier, 2018). Right: Connectivity patterns of dorsal thalamus where Kappel et al. (2021) found a cluster of neurons selective for bout swim. Rth, rostral thalamus; POA, preoptic area; CMid, caudal midbrain; DT, dorsal thalamus; OT, optic tectum; Hyp, hypothalamus.