Investigations on bottom-up and top-down processing in early visual cortex with high-resolution fMRI

We employed cutting-edge high-resolution functional magnetic resonance imaging (fMRI) at sub-millimetre resolution to study visual perception in the human brain. First, we studied bottom-up (i.e. sensory driven) processing in visual cortex. In particular, we investigated how variations in simple physical properties of a visual stimulus affect neuronal activity in visual brain areas. This research was followed by a complementary study on top-down effects. The term ‘top-down’ is used to describe aspects of perception and cognition that are not directly driven by physical properties of the sensory input, but by prior knowledge, expectations, attention, or other high-level mechanisms. In summary, we provide novel insights on the detailed spatial profile of bottom-up and top-down processing in human visual cortex, and have employed a new modelling technique to account for known biases in the high-resolution fMRI signal