Cortical magnification is the difference in the distribution of cortical space encoding different regions of the
visual field (i.e., mm2 of cortical surface per degree of visual field2). Cortical magnification varies with
eccentricity, polar angle, and between individual observers, and is thought to be linked to how well we
perform on many visual tasks at different visual field locations. I use fMRI to measure cortical magnificaiton in
human visual field maps and relate these measurements to psychophysical measurements of visual perception.
My research currently aims to answer the following questions:
1. How do individual differences in localised measurements of cortical magnification relate to individual differences
in visual performance? Do individuals with more cortical surface area dedicated to some region of the visual
field have better vision than someone with relatively less dedicated cortical surface area?
2. We know that more cortical surface (i.e. greater cortical magnification) at some visual field location results in
better visual performance at that location. Fine... but why? Is it because greater cortical magnification results in
a finer sampling of space and features such as spatial frequency and orientation? Or does having more cells with
similar tuning increase SNR? And what are the neural computations that underly these differences in visual performance?
To answer this, we are building a computational model of V1 that incorporates tuning properties of V1 cells
that are known to change with visual field location.
3. How does the organisation of early visual field maps differ between adults and children? Do any differences in
cortical magnficiaton parallel differences in visual perception between adults and children?