Collaborative Research: NSC-FO: Active vision during natural behavior: More than meets the eye?

Vision is a process by which the image falling on the eyes is processed by specialized neurons within visual brain areas. Neurons in the early stages of visual processing convey information about small bits of the visual scene, like pixel-detectors in a camera. For example, a neuron in visual cortex might respond best to a small white bar at a particular location in visual space.

Should this example neuron respond differently when the white bar is part of an object that we have seen before, or one that we are moving towards? Psychology might suggest so, but for almost 60-years, most scientists studying the neural basis of visual perception have implicitly assumed that responses of neurons in visual cortex depend only on the visual image falling on the eyes.

It is increasingly clear that neurons in the visual cortex do indeed care about behavioral context – as well as the state of the brain itself. These external, internal, and contextual factors influence how neurons process the visual scene. Exactly how much these “non-visual” factors influence visual cortical neurons remains a significant open question that this project aims to address.

The experiments will record from neurons in the visual cortex of ferrets as they freely explore a naturalistic environment. Using position and eye-tracking cameras, the project will both recreate a movie of what the ferret saw within the environment, and track other observable variables related to behavior. The movie will then be replayed to the ferret while it is anesthetized, thus directly measuring any differences in neuronal responses to the same visual stimulation in these two very different contexts.

Analysis will compare the physiological quality and statistical properties of neuronal responses across naturalistic and anesthetized conditions to quantify the contribution of natural context to neuronal responses. Results will relate the differences in the freely moving context to specific sources, like motor actions such as eye and head movements, familiarity with specific visual features, and their behavioral relevance.

Experiments will inform models for how these sources influence neuronal activity, setting the stage for understanding the function of non-retinal inputs for sensory perception. The project will provide a foundation for long-term studies of natural vision.

This project is funded by Integrative Strategies for Understanding Neural and Cognitive Systems (NCS), a multidisciplinary program jointly supported by the Directorates for Biology (BIO), Computer and Information Science and Engineering (CISE), Education and Human Resources (EHR), Engineering (ENG), and Social, Behavioral, and Economic Sciences (SBE).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.