Manipulating synthetic optogenetic odors reveals the coding logic of olfactory perception

Abstract

How does neural activity generate perception? The spatial identities and temporal latencies of activated units correlate with external sensory features, but finding the principal activity subspace that is consequential for perception, remains challenging. We trained mice to recognize synthetic odors constructed from parametrically-defined patterns of optogenetic activation, then measured perceptual changes during extensive and controlled perturbations across spatiotemporal dimensions. We modelled recognition as the matching of patterns to learned templates, finding that perceptually-meaningful templates are sequences of spatially-identified units, ordered by latencies relative to each other (with minimal effects of sniff). Within templates, individual units contribute additively, with larger contributions from earlier-activated units. Our synthetic approach reveals the fundamental logic of the olfactory code, and provides a general framework for testing links between sensory activity and perception.

Recurrent circuitry is required to stabilize piriform cortex odor representations across brain states

“…We cannot disprove that stabilization involves an elaborate loop from PCx to a downstream area and then back to PCx. Moving forward, recent technical developments that enable optogenetic control of the specific spatiotemporal patterns of OB output ( Chong et al, 2020 ) could be used to examine pattern formation and recovery in PCx more directly.…”

Active sensing in a dynamic olfactory world

“…Duration differences of as little as ~10 ms can also be detected (Li et al, 2014). Thus, the mammalian olfactory system could represent optogenetic stimuli at a time scale of several 10s of Hz (Chong, 2020). Moreover, recent work shows that OB cell populations can follow temporal patterning in natural plumes (Lewis, 2021), and fast temporal properties of odor stimuli such as intermittency, frequency and phase Gumaste et al, 2020) can be accurately recognized (Fig.…”

Transcriptome analysis for the development of cell-type specific labeling to study olfactory circuits

“…Even in imaging applications that can distinguish the cell type based on the soma depth, with the new driver line, it will be possible to investigate the physiology of subcellular compartments, such as the long lateral dendrites, without the need to painstakingly trace back to the somata for cell-type identification. Similarly, investigations of downstream decoding mechanisms, such as one involving precise optogenetic activations of olfactory bulb projections using patterned light stimuli (Chong et al, 2020), may now be done in a cell-type specific manner. Thus, our new tool may bring us closer to understanding how parallel olfactory processing contributes to mechanisms of sensory perception and, ultimately, behaviour.…”