Processing visual information

Vision is an important sense for humans. Understanding how it works can have a profound impact on our lives. Visual processing involves a number of biological systems starting from the eyes to the neurons in the brain. In his thesis Akhil Edadan investigates the processing of visual information by populations of millions of neurons in the brain.

Edadan: "Any image is represented by neurons in the brain with every neuron processing the information from a small region within the image, known as the receptive field (RF) of that neuron. Neurons also interact with one another through intercellular connections and process information from regions outside classical RF, referred to as the extra-classical RF."

These intercellular interactions, Edadan says, are important for the processing of visual scenes that we see in everyday life. "Neuroscientists use computational models to predict the responses of these neurons, which helps to clarify the underlying neural computations. RF modeling is an important tool used to predict neural computations."

Since non-invasive recording techniques, like functional magnetic resonance imaging, measure the responses of populations of neurons, such models are called population RF (pRF) models. "In my research, we extended our understanding of the human visual system in both healthy and diseased using pRF modeling methods. First, we provided evidence that pRF models are indeed reflecting the underlying neural computations. Then we described the neuronal interactions that are responsible for processing natural visual scenes. Finally, in the light of RF interactions, we provide a possible explanation for the visual hallucinations observed in patients with schizophrenia."