Visual experience doesn’t take long to develop in infants

The visual cortex of the brain is responsible for the processing and interpretation of visual information inputted from the eyes. Neuroscientists have believed that this area would take many years to properly develop and for children to understand what they see. A new MIT study suggests, however, that the time it takes to develop the visual cortex may not take as long as expected; in just two to nine months, babies were able to demonstrate preferences between faces, bodies, or scenes as adults normally do. “Babies’ brains look more similar to adults, in more ways, and [at an earlier period in life] than we thought,” comments Rebecca Saxe, the John W. Jarve Professor of Brain and Cognitive Sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study.

The new research was conducted with more than 50 infants, all scanned under the functioning magnetic resonance imaging (fMRI). The visual cortex of all 50+ infants were then examined.

This fMRI was previously used in research conducted more than 20 years ago by Nancy Kanwisher, the Walter A. Rosenblith Professor of Cognitive Neuroscience at MIT. Using the device, Kanwisher discovered the fusiform face area, a region of the visual cortex, that elicits a stronger response to faces than any other visual input. Similarly, Kanwisher and her colleagues identified other parts of the visual cortex that each elicited the greatest response to bodies or scenes. This posed another question to the group: “how do they get there, and how do you build a brain that has such similar structure in each person?”

One direction to find the answer to these questions is to determine when each region first appear in the brain. While scientists long believed that it would take several years of visual input and interpretation to use the region up to its full potential, studies suggest less. In 2017, Saxe and Ben Deen, one of her graduate students, recorded the first successful use of fMRI examination on awake infants, and the data indicated that while they existed, regions responding to faces and scenes were not as highly selective as those of adults. Only 9 infants were examined, however, and the images were not of high-resolution compared to the coils used for adults.

Therefore, for the new research, specialized scanners for more comfortable observation of babies and a total of 90 recruited babies resulted in usable, high-resolution fMRI data from 52 of the babies. This time, the data reveled that there were regions in the visual cortex of infants that selectively responded to faces, body parts, and natural scenes, although the response to natural scenes was not as significant as the others.

Researchers now plan to conduct further research as to why the response to natural scenes was not as strong as the others (faces and other body parts). Images would be displayed on larger screens to better model a natural scene. The scanner would also be changed to near-infrared spectroscopy, which does not require participants to enter a certain machine and allows for the free movement of participants. With this additional study, the team is in hopes of discovering more about the development of the fusiform face area in infants and young children.


Categories: Clinical