Abstract
The ventral visual pathway in humans has a stereotyped functional organization, in which regions selective for specific visual categories are found in approximately the same location in virtually every normal adult. How does this systematic structure arise in development? Are category-sensitive regions largely innately specified and present from early in development, or do they develop gradually, after extensive visual experience with specific categories? Here we develop and apply methods for fMRI in awake infants to address this question. We scanned 2-8-month-old infants (N = 17, 63 total scan sessions) while viewing infant-friendly videos depicting faces, bodies, inanimate objects, natural scenes and scrambled scenes. Several novel methodological approaches were employed, including infant-sized head coils, quiet pulse sequences, and a combination of novel and extant data analysis techniques for reducing the impact of head motion. In infants with enough low-motion data (n=9 infants), we observed face- and scene-preferring in the same locations as the corresponding category-sensitive extrastriate regions in adults. These response profiles were replicated in independent data, and in two sets of movie stimuli. At least in some cases, responses in these regions were better explained by high-level category preferences than by low-level stimulus features such as spatial frequency and rectilinearity. However, strongly selective regions, preferring one visual category over all others, were not observed in infants, in contrast to adults. These results demonstrate that the location of multiple category-sensitive regions is already staked out in cortex within a few months after birth, but strong adult-like category selectivity does not emerge until later in development.
Meeting abstract presented at VSS 2016