Young children's behavioral and neural responses to peer feedback relate to internalizing problems

Time-frequency analysis methods and their application in developmental EEG data

EEG provides a rich measure of brain activity that can be characterized as neuronal oscillations. However, most developmental EEG work to date has focused on analyzing EEG data as Event-Related Potentials (ERPs) or power based on the Fourier transform. While these measures have been productive, they do not leverage all the information contained within the EEG signal. Namely, ERP analyses ignore non-phase-locked signals and Fourier-based power analyses ignore temporal information. Time-frequency analyses can better characterize the oscillations contained in the EEG data. By separating power and phase information across different frequencies, time-frequency measures provide a closer interpretation of the neurophysiological mechanisms, facilitate translation across neurophysiology disciplines, and capture processes not observed by ERP or Fourier-based analyses (e.g., connectivity). Despite their unique contributions, a literature review of this journal reveals that time-frequency analyses of EEG are yet to be embraced by the developmental cognitive neuroscience field. This manuscript presents a conceptual introduction to time-frequency analyses for developmental researchers. To facilitate the use of time-frequency analyses, we include a tutorial of accessible scripts, based on Cohen (2014), to calculate time-frequency power (signal strength), inter-trial phase synchrony (signal consistency), and two types of phase-based connectivity (inter-channel phase synchrony and weighted phase lag index).

Children's shyness and neural responses to social exclusion: Patterns of midfrontal theta power usually not observed until adolescence

Adverse peer experiences, such as social exclusion, are known risks for socioemotional problems among shy youth. Yet, little is known about how shy children and adolescents process social exclusion in the brain and whether these responses are amplified in adolescence. Using the Cyberball task, we examined mediofrontal theta (4-7 Hz) event-related EEG spectral power during conditions of fair play and social exclusion in 122 participants (58 children, ages 10-12 years, and 64 adolescents, ages 14-17 years). Age effects of the task showed that adolescents displayed heightened theta power to both outright rejection and baseline "not my turn" events, whereas children showed higher theta power to rejection compared with "not my turn" events. Further results on individual differences showed that children with relatively higher levels of shyness displayed enhanced theta power to both rejection and "not my turn" events-a pattern that also was observed in adolescents. These findings suggest that a pattern of heightened neural sensitivity to both outright social exclusion and threats of exclusion, which is the norm by adolescence, also is observed in children with higher levels of shyness. The similar neural response pattern might be driven by salient social motivations that similarly modify the social cognition and behaviors of these groups and might reflect neural antecedents of rejection sensitivity.

Behavioral inhibition and EEG delta-beta correlation in early childhood: Comparing a between-subjects and within-subjects approach

Heightened delta-beta correlation has been conceptualized as reflecting exaggerated neural regulation and has been implicated in anxiety. Behavioral inhibition (BI) is a temperament characterized by wariness to novelty and is a robust predictor of anxiety, but delta-beta correlation has not been investigated in relation to childhood BI. We examined the relation between BI and between-subjects (i.e., across participants) and within-subjects (i.e., across data epochs) measures of baseline EEG delta-beta correlation in 118 children. Using a between-subjects measure, children scoring high on BI had higher delta-beta correlation relative to low BI children at frontal and central, and marginally higher in parietal, brain regions. Using a within-subjects measure, continuous BI scores were positively correlated with central and parietal delta-beta correlation. Delta-beta correlation may be a neural correlate of BI in childhood that displays differences in region specificity, correlation strength, and variability of correlation values when comparing between- and within-subjects measures.