Linda Stenbacka

Imaging of Peripheral Vision and Dorsal Visual Stream in Human Cortex Linda Stenbacka

This thesis work examines visual encoding in hierarchically low level cortical visual areas in human brain especially in cortical representation of visual field periphery with magnetoencephalography and functional magnetic resonance imaging. It maps the representation of peripheral visual field, identifies a putative human homologue of functional area V6 of the macaque, and shows that human V6 activates during eye-movements and responds to visual motion at short latencies. In addition, this work shows that peripheral vision is functionally related to eye-movements and connected to rapid stream of functional areas processing visual motion and demonstrates two examples of top-down modulation of neural processing in visual cortex; one that is related to dorsal stream activation and another local signal enhancement at the attended region reflecting local feed-back signal. In addition, this work compares two methods of neuromagnetic source modeling and studies some potential confounding factors in vision studies such as light scatter inside the eye, eye movements, and attention.