Contextual modulation

We propose a novel method to predict contextual modulation of local field potential (LFP) gamma synchronization and multi-unit activity (MUA) in a single framework. Convolutional neural networks are state-of-the-art models of the primary visual cortex (V1). Sensory processing in V1 is determined by contextual modulation via feedback and recurrent connections. However, the computational goal and the neural implementation that shape V1 activity are not yet fully understood. We use transfer learning to use an object recognition convolutional neural network (VGG-16) to predict firing rates and gam

Perceptual decision-making is crucial for survival, requiring the integration of dynamic sensory evidence from the environment with internal state variables (e.g. context, priors, value) to choose an appropriate action plan. Neural correlates of perceptual decisions are more distributed than once thought, having been found within the cortex, striatum, and superior colliculus (SC). Recent work has suggested a potentially novel node in this network - the midbrain reticular nucleus (MRN) - which was one of the few regions that encoded visual and action selection signals in a brain-wide survey of

A central goal of vision science is to understand the principles underlying the perception and neural coding of the complex visual environment of our everyday experience. In the visual cortex, foundational work with artificial stimuli, and more recent work combining natural images and deep convolutional neural networks, have revealed much about the tuning of cortical neurons to specific image features. However, a major limitation of this existing work is its focus on single-neuron response strength to isolated images. First, during natural vision, the inputs to cortical neurons are not isolate

The responses of neurons in primary visual cortex depend strongly on the spatial context in which stimuli are embedded. This context-dependence has been theorized to reflect efficient and/or predictive coding of natural scenes. Critical tests of these theories in a generic form for natural images are currently lacking , because it is unclear how predictions, and measures of predictability, should be operationalized for natural scenes. Further, it is unclear whether there is just one type or level of predictability given the hierarchical processing in the primate visual system. Here, we traine

…these responses, a phenomenon known as contextual modulation. Here we consider 3 types of contextual modulation: i) classical surround suppression: the response of cells in V1 decreases when the stimulus size is increased beyond the RF size; ii) inverse surround suppression: neurons in layer L2/3 –but not layer L4– of mouse V1 respond to a lack of contrast in their RF when the surround is filled with

Higher-order thalamic nuclei have extensive connections with various cortical areas. Yet their functionals roles remain not well understood. In our recent studies, using optogenetic and chemogenetic tools we manipulated the activity of a higher-order thalamic nucleus, the lateral posterior nucleus (LP, analogous to the primate pulvinar nucleus) and its projections and examined the effects on sensory discrimination and information processing functions in the cortex. We found an overall suppressive effect on layer 2/3 pyramidal neurons in the cortex, resulting in enhancements of sensory featu