Building a logic by which olfactory representations are organized at the molecular and neurophysiological levels is essential for understanding how we interpret and act within the chemical world. Recent developments in optical methods for have led to unprecedented access for recording and manipulating olfactory circuits. These talks highlight new insights leveraging technical advances to show how the olfactory system encodes maps of chemical space in diverse neural populations.
Tuning, Sequences and Geometry of Olfactory Representations
Jonathan V. Gill
NYU Langone Health, Rinberg Lab
Mice can rapidly identify odors within a single sniff across a wide range of concentrations. How are odors encoded, giving rise to this ability? In the mouse olfactory bulb, mitral and tufted cells (MTCs) respond to odors by changing both the rate and timing of action potentials relative to inhalation, resulting in reliable, odor specific sequences that evolve over a single sniff. Using 2-photon calcium imaging, and the ultra-fast calcium indicator jGCaMP8f, we measured responses across many odors and MTCs with sub-sniff temporal resolution and explored how rate and timing-based odor encoding are organized and related. We found that 1) MTC odor tuning was constrained to a low-dimensional subspace, 2) activity sequences propagated across the odor encoding subspace with a consistent speed and trajectory, and 3) the earliest responses in the sequences were consistent across concentrations, defining a temporal window of concentration invariant identity coding
Towards biophysical models of family-wide chemosensory representation
Timothy E. Holy
Washington University in St. Louis
In sensory systems like color vision, a quantitative understanding of receptor tuning has enabled technological and medical breakthroughs while also informing our ideas about optimal coding and evolution. Developing a similar understanding of chemosensation has been a longstanding goal for many labs. In this talk, I’ll argue that the mouse V1R receptor family presents unusual opportunities for a parametric, family-wide biophysical model of receptor-ligand interactions.