Vision Systems Physiology: Projects

People in alphabetical order

Visual Coding

H. Heikkinen, F. Sharifian, S. Vanni

What are the principles of coding in the visual cortex? How are the increases and decreases of activation in brain imaging related to visual information processing? Recently we found that interactions between two or more fMRI responses for visual objects are commensurate with decorrelation of the activation patterns for the component responses. We are pursuing both experimental and theoretical studies on visual coding and interaction, and aim to confirm that cerebral cortex decorrelates activation patterns of neural populations and try to model known single neuron level interactions.

Pathophysiology, rehabilitation, and visual awareness in hemianopia

J. Silvanto, S. Vanni

Residual vision after postchiasmatic lesion refers to high-threshold detection of visual environment in a clinically blind hemifield. Interestingly, long and intensive training is known to change the detection and letter-discrimination thresholds in such blind field, as well as brain activation patterns. It is however unknown how is visual environment represented after pathological changes, prohibiting normal processing in the visual system. Together with Antti Raninen (Univ. Helsinki), Risto Näsänen (Univ. Oulu), and Juha Holopainen (Helsinki University Central Hospital) we are pursuing studies which try to analyze the individual functional anatomy after plastic changes in the visual system.

Vision Systems Physiology