Sensory coding

While sensory coding is traditionally thought of as a process independent of behavioral state, modern studies showcase potent modulatory effects of movement on sensory neurons. Intriguingly, these effects are not uniform and can differ between species. In insects and rodents, visual responses increase dramatically when the animal is moving, whereas in primates locomotion has a weak impact on responses in the primary visual cortex (V1). These differences raise questions about the existence and universality of computational principles underlying sensory coding during behavior. We take a normativ

The role of feedback in sensory systems remains a major puzzle in neuroscience. Classical computational theories such as hierarchical predictive coding[1] or hierarchical Bayesian inference[2] postulate abstract normative goals for the role of feedback connections. However, predictions derived from these theories are typically specified at the level of individual neurons. Whether feedback shapes collective properties of neural populations and how such changes may impact encoding of sensory signals remain unknown. Here we tackle these questions directly by studying the population coding of na

…modulatory effects of movement on sensory coding. Surprisingly, these effects are not consistent across species. For example, in rodents and insects locomotion increases the magnitude of visual responses [1-3], while in primates, locomotion has a weak suppressive influence [4]. These differences raise intriguing questions about the computational purpose of such modulations and the generality of the underlying principles of sensory processing. Here, we address these questions from a theoretical perspective. Our approach is groun

…systems, including the internal mechanosensory organs. However, the progress has been slow due to technical hurdles: the sensory neurons are deeply buried inside the body and are not readily accessible for direct observation, the projection patterns from different organs or body parts are complex rather than converging into dedicate brain regions, the coding principle cannot be directly adapted from that learned from conventiona

Pyramidal neurons in mammalian cortical layer 5 (L5) send long-range projections to other cortical areas and subcortical structures. Understanding the outputs of the cortex thus requires understanding the activity of these neurons. Thick-tufted L5 pyramidal neurons generate two types of action potentials: 1) the classic sodium-potassium action potentials (Na-K APs) generated at the axon hillock, which propagate down the axon to trigger neurotransmitter release and backpropagate across the soma and dendritic tree, and 2) slow calcium spikes in the apical dendrite, triggered by the coincidence o

Sensory coding in olfaction remains poorly understood. Unlike in vision, where the stimulus space is well-characterized, the complexity of the "odor space" and the complexity of the olfactory receptor (OR) repertoire has hindered our understanding of odor coding and processing. There is no consensus on key defining features of odor sensation, such as the dimensionality of odor perceptual or odor receptor space. It is commonly conjectured that the ORs transform the high-dimensional "chemical space" to a relatively low-dimensional space of neuronal representations. We developed a novel method f

…single neurons can fluctuate between coding one vs. the other(s) across some time period, i.e. a form of neural multiplexing in the time domain (Caruso et al., 2018). However, it is not known (a) whether such fluctuations occur specifically when two distinct objects are present and not in other cases, and (b) how fluctuations in individual neurons might be coordinated with one anot

…By deploying an efficient coding argument, we predict that changes in the structure of receptive fields across visual space increase the efficiency of sensory coding. To test this experimentally, developed a simple, novel imaging system that is indispensable for studies at this scale. In agreement with our predictions, we c

…presenting an interesting challenge in sensory coding. I will talk about recent work from the lab showing that (1) human and animal blends can be distingui