Sensory stimuli

…expression in response to painful stimuli. But recent studies suggest that physiological responses (heart rate, cortisol levels, etc.) to noxious stimuli are heightened compared to neurotypical individuals. The neural valence system is a network of interconnected brain regions that integrates downward sensory stimuli with upward signals reflecting the current physiological state

Sensory stimuli, including auditory, visual, or tactile inputs, can elicit varied brain and bodily responses contingent upon their novelty and salience levels. Human functional magnetic resonance imaging (fMRI) studies have delineated brain regions involved in salience detection, suggesting a feedforward propagation of brain activity from sensory to associative areas. Longstanding theories have emphasized the significance of the Locus Coeruleus – Norepinephrine (LC/NE) system in governing the levels of salience in sensory signals. However, causal evidence linking LC activity to alterations in

The medial prefrontal cortex (mPFC) plays a crucial role in integrating sensory input for learned stimulus-response associations. However, the link between sensory stimuli and changing behavioral relevance remains poorly understood. We studied how sensory stimuli and neural representations of associated behaviors emerge in mPFC during avoidance learning.We performed mobile population calcium imaging in mice mPFC during an active avoidance task. In this task, mice learned to avoid an aversive foot shock associated with conditioned tone stimuli CS1 and CS2. CS1 was first followed by the shock in

…in salience detection and in gating sensory stimuli to adaptively shape behavior. The aim of the project is to test whether failure in the encoding

Cortical circuits embody remarkably reliable neural representations of sensory stimuli that are critical for perception and action. The fundamental structure of these network representations is thought to arise early in development prior to the onset of sensory experience. However, how these endogenously generated networks respond to the onset of sensory experience, and the extent to which they reorganize with experience remains unclear. Here we examine this ‘nature-nurture transform’ using chronic in vivo calcium imaging to probe the developmental emergence of the representation of orientatio

A central problem in systems neuroscience is to understand the relationship between sensory stimuli, neural activity, and decision-making behavior. Latent linear dynamical systems (LDS) models are one powerful framework for characterizing these relationships. For example, LDS models can be used to describe the hidden dynamics that govern how an animal's decision-making strategy evolves continuously over time. However, fitting LDS models to data using standard methods such as the expectation-maximization (EM) algorithm is computationally expensive and prone to local optima. We address these sho

…larval zebrafish subjected to diverse sensory stimuli. Fish swim in short and discrete burst-like motions bouts. We construct a maximally predictive state space by stacking consecutive bouts, and then investigate the time evolution of state-space densities through transfer operators. Their spectral decomposition reveals two stereotyped long time

…or to extract different features from sensory space (Deny et al., 2017). Thus far, our understanding of the complex transformations by neurons has been largely informed by experiments which directly activate synaptic inputs on dendrites. However, these do not consider how natural and complex stimuli map to neuronal inputs. Our study uses etho

…which controls how external sensory stimuli are represented in the brain. In contrast, the neural mechanisms controlling the selection of representations held ‘in mind’, in working memory, are unknown. In this talk, I will present evidence that the prefrontal cortex controls working memory by selectively enhancing and transforming the contents of working memory. In particular, I will show how the neural rep

Discriminating distinct objects and concepts from sensory stimuli is essential for survival. Our brains accomplish this feat by forming meaningful internal representations in deep sensory networks with plastic synaptic connections. Experience-dependent plasticity presumably exploits temporal contingencies between sensory inputs to build these internal representations. However, the precise mechanisms underlying plasticity remain elusive. We derive a local synaptic plasticity model inspired by self-supervised machine learning techniques that shares a deep conceptual connection to Bienenstock-Coo

The ability to associate sensory stimuli (e.g., apples and cookies) with abstract knowledge (e.g., “healthy” versus “unhealthy”) is critical for survival. How are these associations implemented in the brain? And what governs how neural activity changes during abstract knowledge acquisition? To investigate these questions, we consider a circuit model that learns to map sensory stimuli into abstract categories via gradient-descent plasticity. We focus on typical neuroscience tasks (simple, and context-dependent categorization), and use simulations and mathematical analysis to uncover how neural

…contain significant information about sensory s

…trained to make decisions based on sensory stimuli and on past events. While mice made these decisions, we causally probed the roles of cortical areas and recorded from thousands of neurons throughout the brain, with an emphasis on frontal cortex. The results are not what we thought based on textbook notions of how the brain works. This talk is based on work led by Nick Steinmetz, Peter Zatka-Haas, Armin Lak, and Pip Coen, in the laboratory I s

…system that learns and adapts to sensory information. Based on our experience we can predict what a wooden surface will feel like, that fire is hot, and that a gentle caress from a partner can be soothing. But our sensory experience of the world is not static – warm water can feel like fire on sunburned skin and the gentle brush of our clothes can be excruciating after an injury. In pathological conditions such as chronic pain, changes in nervous system function can cause normally innocuous sen

…of cells (including cells in primary sensory cortex) do not appear to fire in a task-related manner and are often neglected from analysis. We recently used a novel single-trial, spike-timing-based analysis to show that both classically responsive and non-classically responsiv

Neural and behavioral responses to sensory stimuli are notoriously variable from trial to trial. Does this mean the brain is inherently noisy or that we don’t completely understand the nature of the brain and behavior? Here we monitor the state of activity of the animal through videography of the face, including pupil and whisker movements, as well as walking, while also monitoring the ability of the animal to perform a difficult auditory or visual task. We find that the state of the animal is continuously changing and is never stable. The animal is constantly becoming more or less activat

Despite the consistency of symptoms at the cognitive level, we now know that brain disorders like Autism and Schizophrenia can each arise from mutations in >100 different genes. Presumably there is a convergence of “symptoms” at the level of neural circuits in diagnosed individuals. In this talk I will argue that redundancy in neural circuit parameters implies that we should take a circuit-function rather that circuit-component approach to understanding these disorders. Then I will present our recent empirical work testing a circuit-function theory for Autism: the idea that neural circuits sho

Inhibitory microcircuits play an important role regulating cortical responses to sensory stimuli. Interneurons that inhibit dendritic or somatic integration are gatekeepers for neural activity, synaptic plasticity and the formation of sensory representations. We have been investigating the synaptic plasticity mechanisms underlying the formation of ensembles in olfactory and orbitofrontal cortex. We have been focusing on the roles of three inhibitory neuron classes in gating excitatory synaptic plasticity in olfactory cortex- somatostatin (SST-INs), parvalbumin (PV-INs), and vasoactive intestin

The dynamic nature of sleep in most animals suggests distinct stages which serve different functions. Genetic sleep induction methods in animal models provide a powerful way to disambiguate these stages and functions, although behavioural methods alone are insufficient to accurately identify what kind of sleep is being engaged. In Drosophila, activation of the dorsal fan-shaped body (dFB) promotes sleep, but it remains unclear what kind of sleep this is, how the rest of the fly brain is behaving, or if any specific sleep functions are being achieved. Here, we developed a method to record calci