Hidden in plain sight.

Context controls the activity of sensory neurons.

A Disinhibitory Circuit for Contextual Modulation in Primary Visual Cortex.

Context guides perception by influencing stimulus saliency. Accordingly, in visual cortex, responses to a stimulus are modulated by context, the visual scene surrounding the stimulus. Responses are suppressed when stimulus and surround are similar but not when they differ.

Feedback generates a second receptive field in neurons of the visual cortex.

Animals sense the environment through pathways that link sensory organs to the brain. In the visual system, these feedforward pathways define the classical feedforward receptive field (ffRF), the area in space in which visual stimuli excite a neuron. The visual system also uses visual context-the visual scene surrounding a stimulus-to predict the content of the stimulus, and accordingly, neurons have been identified that are excited by stimuli outside their ffRF.

Stimulus relevance modulates contrast adaptation in visual cortex.

A general principle of sensory processing is that neurons adapt to sustained stimuli by reducing their response over time. Most of our knowledge on adaptation in single cells is based on experiments in anesthetized animals. How responses adapt in awake animals, when stimuli may be behaviorally relevant or not, remains unclear.

Local Circuits for Contrast Normalization and Adaptation Investigated with Two-Photon Imaging in Cat Primary Visual Cortex.

Unlabelled: Sensory neurons encode stimulus intensity in their instantaneous spike rate and adjust the set-points of the stimulus-response relationships by adaptation. In the visual cortex, adaptation is crucial because the mechanism of fast gain control (normalization) increases the contrast sensitivity of individual neurons at the cost of encoding a far narrower range of contrasts than is encountered in natural scenes. The mechanism of adaptation, however, is a slow process and has a time constant of seconds.

HelioScan: a software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility.

Intravital microscopy such as in vivo imaging of brain dynamics is often performed with custom-built microscope setups controlled by custom-written software to meet specific requirements. Continuous technological advancement in the field has created a need for new control software that is flexible enough to support the biological researcher with innovative imaging techniques and provide the developer with a solid platform for quickly and easily implementing new extensions. Here, we introduce HelioScan, a software package written in LabVIEW, as a platform serving this dual role.