In an investigation of neural connectivity in 30 infants ranging from six to 57 days old (with an average age of 27 days), neuroscientists found that circuit wiring precedes, and thus may guide, regional specialization, shedding light on how knowledge systems emerge in the brain. An anonymous reader shares a report from Scientific American: In the study, published Monday in Proceedings of the National Academy of Sciences USA, the researchers looked at two of the best-studied brain networks dedicated to a particular visual function — one that underlies face recognition and another that processes scenes. The occipital face area and fusiform face area selectively respond to faces and are highly connected in adults, suggesting they constitute a face-recognition network. The same description applies to the parahippocampal place area and retrosplenial complex but for scenes. All four of these areas are in the inferior temporal cortex, which is behind the ear in humans. The team used a technique called resting-state functional magnetic resonance imaging (rsfMRI), which measures the level of synchronization of activity in different brain regions to assess how connected they are. The infants were scanned while sleeping and tightly swaddled. “Getting fMRI data from newborns is a new frontier in neuroimaging,” says neuroscientist and lead study author Frederik Kamps, now at the Massachusetts Institute of Technology. “You need participants’ head to be still, and a sleeping baby is one that’s willing to lie still.”
The researchers found that the face regions were highly connected to one another but not to the scene regions, and vice versa, at this young age. It would be months before they became selective for faces or scenes, suggesting connectivity precedes the development of function. The team also assessed connections between these regions and the part of the brain where visual input first arrives from the retina: the primary visual cortex, or V1. This region is structured so that such inputs from the center of the retina arrive at a different area than those from the periphery of the field of vision, forming a map of the visual world. The face network was strongly connected to V1’s central area, while the scene network was more tightly linked to its peripheral area. This arrangement likely relates to the fact that we usually fixate on faces, whereas scenes extend across our entire visual field. These networks, present in an infant’s earliest days, are therefore connected so as to receive the most appropriate input for the function they will eventually perform. Psychologist Daniel Dilks of Emory University has an eye on possible clinical applications. “He is particularly interested in two neurodevelopmental disorders that are thought to involve differences in brain wiring: People with autism have social impairments that may relate to face processing. And a condition called Williams syndrome causes problems with navigation,” reports Scientific American.
“Siblings of children with autism could be studied to ask whether connectivity in face regions might predict the onset of the condition, which is usually not diagnosed until at least two years of age. Dilks also hopes to study babies with Williams syndrome to ask whether connectivity between scene-processing regions is a problem. “