Effects of diet on the neurodevelopment of 2- and 6-month-old infants determined by EEG Microstates

Authors: GILBREATH, DYLAN - University Arkansas For Medical Sciences (UAMS); HAGOOD, DARCY - Arkansas Children'S Nutrition Research Center (ACNC); DOWNS, HEATHER - Arkansas Children'S Nutrition Research Center (ACNC); LARSON-PRIOR, LINDA - University Arkansas For Medical Sciences (UAMS)

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/19/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Throughout infancy, the brain undergoes rapid changes in structure and function that are sensitive to environmental influences such as diet. To further explore the effect diet has on cognitive development and function, electroencephalography (EEG) can be used as it is a direct measure of neuronal activity that is associated with cognitive processes. One measure of this activity is microstates, which are the scalp current densities reflective of the patterning of the global activation of neurons. Task-free baseline EEGs were collected from infants fed with human milk (BF), dairy-based formula (MF), or soy-based formula (SF) at 2 and 6 months of age to explore differences in microstates, and to compare these infant microstates to those of adults. Both the 2 and 6 month olds had very similar microstates to those of adults, and there were significant differences between dietary groups in the 6-month-olds for a specific microstate class involved with the prefrontal region of the brain. Because of the high fidelity to the adult microstates, we believe that these significant differences are due to the subtle differences in neuromaturation between the dietary groups that is manifesting through these differences in global neuronal activity.

Technical Abstract: Introduction Infant diet plays a critical role in shaping the developing nervous system through providing essential nutrients that effect myelination, neurogenesis, synaptogenesis, and cognitive development. These developing neuronal processes are sensitive to various nutrient deficiencies throughout infancy and early childhood, and these insults often produce enduring effects. However, little research has been done exploring how different healthy infant diets may affect this process. While breastmilk is widely regarded as being the optimal source of nutrients, little is known on its actual effect on the function and maturation of the brain. Recent advances in neuroimaging techniques have expanded our conceptualization of dynamic neuronal function. Electroencephalography (EEG) is a non-invasive, direct measure of neuronal activity, and can be used to measure microstates which are transiently stable scalp potentials that occur on the order of milliseconds. These microstates have distinct topologies referred to as classes, with each class indicating of a different pattern of global neuronal activity. Currently, it is unknown the extent to which infant microstates are comparable to adult microstates, and whether these microstates can be used as an indicator of neuronal development or maturation. We hypothesize that infant microstates will be spatially similar to the adult microstates, and that children fed breastmilk (BF) will demonstrate the most similarity due to a higher degree of neuronal maturation than their dairy (MF) or soy (SF) formula counterparts for each age group. Methods Resting state, eyes open EEGs were collected from infants at 2 months (n = 316; BF = 109, MF = 102, SF = 105) and 6 months (n = 419; BF = 135, MF = 143, SF = 141) using a 128-sensor net. The Harvard Automated Processing Pipeline for EEG was used to preprocess EEG data. Data were band-pass filtered (.5-45 Hz), referenced to a global mean using REST, and Morlet wavelet filtered to remove artifacts. EEGs were then rejected for the following criteria: >70% bad channels or segments, an R Pre/Post wavelet thresholding value below .2 for frequencies in our range of interest. 10 artifact free, 10 second segments were then averaged for each subject, and this average was used for further analysis. Microstates were calculated for each individual using k-means clustering (k = 5, repetitions = 20), before being calculated for the grand average, sorted by class based upon an adult template, and backfit to the individual. Significance was tested using a TANOVA to determine topographical differences between dietary groups for each age group and microstate class. Microstate analysis and statistical testing was conducted using the MICROSTATELAB toolbox for EEGLAB. Results While statistical significance was not achieved for the dietary groups in 2-month-olds in any microstate class, microstates at this age as well as in the 6-month-olds were found to closely resemble adult microstates, with a high spatial correlation ranging from 85-97%. In the 6-month-olds, microstate C was found to be significantly different between groups (p = .014), with topographic differences being largely prefrontal. Because of the high fidelity to the adult maps, we believe that these significant differences are due to the subtle differences in neuromaturation between the dietary groups that is manifesting through these differences in global neuronal activity. Conclusion Despite undergoing massive neuronal changes during infancy, resting state networks and their microstate correlates seem to not only exist at this early time point, but closely resemble the adult microstates. This is one of the first studies demonstrating this similarity between adults and infants, and the first study seeking to explore the effects of diet on these microstates. Future studies will assess mo