Caregiver Cumulative Cortisol Mediates Deviations in Functional Connectivity in Infants: A Novel fNIRS Study

The effects of chronic physiological stress on the developing infant brain have long been recorded by developmental scientists. Infants who have experienced chronic physiological stress, as elucidated from maternal physiological stress, have been found to have deviations from the "typical" developing brain's trajectories (Troller-Renfree, 2020). These alterations, usually consisting of an overabundance of low frequency EEG power and a relative paucity of high-frequency power, have been attributed to a developmental delay entitled the "maturational lag" which has been postulated to describe a delay in the development of central nervous system, and in particular, cortical development (Corning, Steffy, Anderson & Bowers, 1986). My past research has extended these findings, looking into the differentiations between EEG power growth curves of infants mediated by chronic caregiver stress and its implications on cortical development. Not much research has been done using functional brain imaging techniques to determine whether these electrophysiological and structural changes are also marked by changes in hemodynamic responses as well when comparing infants with caregivers with and without chronic stress, and my proposed research aims to be some of the first research to do so.
Functional near infrared spectroscopy (fNIRS) is a relatively novel method in which scientists can elucidate data about the hemodynamic changes happening in the brain. Though fMRI is the most commonly used technique to study these changes, its bulky and static nature makes it difficult to use on infants. fNIRS is comparatively smaller and portable, and much more suited to research in infancy.This method makes inferences about the brain's cytoarchitecture by examining values of connectivity/synchrony between neurons as they communicate with each other across the brain. Many of these studies have been done using fMRI, but more recently, scientists have begun to use fNIRS to...