Joint experience-dependent representations of odors and temporal context in the zebrafish homolog of piriform cortex

Intelligent behavior necessitates experience-dependent internal representations of pertinent data. The study investigated representational learning within telencephalic area pDp of adult zebrafish, which is the zebrafish counterpart of piriform cortex. The neural activity was monitored through multiphoton imaging, while the head-fixed fish underwent an odor discrimination exercise.

The collective neural dynamics could be broken down into separate modes, each comprising a distributed activity pattern across neurons with mixed selectivity. These modes encoded three key features: the identity of the odor, its novelty, and the passage of time.

Training sessions refined the fish's ability to discern novelty, bolstered the response to specific odors, and geometrically segregated the representational manifolds. The plasticity induced by experience extended across chemically related stimuli. The findings could be duplicated in a model that assumes linear interactions among the activity modes encoding novelty, identity, and time.

The researchers concluded that pDp integrates olfactory and temporal information necessary for episodic memory. Experience amplifies the availability and adaptability of information, suggesting that pDp facilitates brain-wide learning by organizing olfactory and time-related information on neural manifolds.