Dr. Michelle Jetha will present on her most recent research with a talk entitled “The Stability of Visual ERP Components in Young Children.”
March 4, 2016
Event-related potentials (ERPs) are being increasingly used as neurophysiological markers of emotion regulation, attentional biases towards emotional information, and emotion-cognition integration in developmental studies to characterize individual differences in temperament, vulnerability for affective psychopathology, and longitudinal change. Traditional ERP measures in such studies used with children include late segments such as the P300 and slow wave components, but recent work has shown that early components also reflect individual differences in processing of emotional and emotional-cognitive stimuli. However, while much is known about the reliability of the late components in adults and some studies have included children, little is known about the earlier components such as the P100, N170, VPP and N2 that are sensitive to visual processing and are moderated by attentional resources accrued to the tasks as a function of emotional valence. In addition, more studies are needed to assess the stability of ERPs over childhood to determine the normal range of variability over time and how the variability of components is influenced by maturation and gender. There is much change both psychologically and neurophysiologically over early childhood, including at the start of school, from 5 to 6 years of age. The current longitudinal study reports general maturational changes for several early components, with earlier components, such as the P1, N170 and VPP, showing increases in amplitude over time, while the later N2 component showed a decrease in amplitude over time. Latencies for all components with the exception of the N170 decreased over this period. Such changes over childhood are expected as there are dramatic changes in neural development and reorganization, including changes in grey and white matter (e.g., changes in synaptic density and myelination) that influence the amplitude, latency, and topography of ERPs. In this study, data from 110 children were drawn from a longitudinal clinical trial of a multi-component intervention for children with early onset aggression. For children who did not receive intervention, ERP waveforms were extracted during a go/nogo paradigm and were assessed in kindergarten and again in 1st grade. Results indicate that amplitude and latency of early visual components (P1, N170, VPP) and the later medial frontal component (N2) showed good to very good stability over this time period. Pearson correlations ranged from .48 for the frontal N2 at Fz to .69 for occipital P1at Oz. This study provides the first evidence on the longitudinal stability of these components in early childhood and has implications for the use of these metrics as trait-like markers for individual differences. This finding is important as ERPs are often used to reflect processing of information – both cognitive and emotional – increasingly in children as well as traditionally in adults. Importantly, we also demonstrate good to very-good rank order stability of visually-evoked components over the time period, despite the significant change in absolute amplitude and latency over the same time period. Individual differences in ERP amplitudes may partly result from differences in variables such as cortical folding and skull thickness; however, as has been indicated by an increasing number of studies, such individual differences often reflect processing differences that are reflective of temperament and/or vulnerability for affective psychopathology.
Michelle Jetha is Assistant Professor of psychology in the school of School of Science & Technology.