Novelty N2-P3a Complex and Theta Oscillations Reflect Improving Neural Coordination Within Frontal Brain Networks During Adolescence

Adolescents are easily distracted by novel items than adults. Maturation of the frontal cortex and its integration into widely distributed brain networks may result in diminishing distractibility with the transition into young adulthood. The aim of this study was to investigate maturational changes of brain activity during novelty processing. We hypothesized that during adolescence, timing and task-relevant modulation of frontal cortex network activity elicited by novelty processing improves, concurrently with increasing cognitive control abilities. A visual novelty oddball task was utilized in combination with EEG measurements to investigate brain maturation between 8–28 years of age (n = 84). Developmental changes of the frontal N2-P3a complex and concurrent theta oscillations (4–7 Hz) elicited by rare and unexpected novel stimuli were analyzed using regression models. N2 amplitude decreased, P3a amplitude increased, and latency of both components decreased with age. Pre-stimulus amplitude of theta oscillations decreased, while inter-trial consistency, task-related amplitude modulation and inter-site connectivity of frontal theta oscillations increased with age. Targets, intertwined in a stimulus train with regular non-targets and novels, were detected faster with increasing age. These results indicate that neural processing of novel stimuli became faster and the neural activation pattern more precise in timing and amplitude modulation. Better inter-site connectivity further implicates that frontal brain maturation leads to global neural reorganization and better integration of frontal brain activity within widely distributed brain networks. Faster target detection indicated that these maturational changes in neural activation during novelty processing may result in diminished distractibility and increased cognitive control to pursue the task

Brain oscillations evoked by the face of a loved person

Previous studies have shown a close interrelation between emotional processing and memory processes using facial stimuli and applying the concept of oscillatory brain dynamics. Amending prior findings the influence of neural correlates related to the emotional state termed "romantic love" was investigated. Specifically, the effect of feelings of love on face perception was of interest. Pictures of a "loved person" were presented to female subjects and the elicited responses were compared with responses to pictures showing faces of a "known and appreciated person" or an "unknown person" during EEG recordings (n=20 females). As a control condition light stimulation was employed. The sequence of faces shown was presented in random and block-design. EEG data was analyzed considering maximum amplitudes and topographical differences within the conventional frequency bands of delta, theta, alpha, beta and gamma. Differences between light and face stimuli were found in the delta and theta bands and differences between the face types and the two designs were found in the delta band. The delta response to the picture of the "loved person" showed significantly higher amplitude values, not only in comparison with the "unknown person", but also with the picture of the "appreciated person". Frontal lobes appear to react to different types of facial stimuli with specific increases in delta responses. The difference between the response to the "loved person" and of the "known and appreciated person" reflects the component of the emotion denoted as love. The findings and their interpretations are discussed within the framework of event-related oscillations and complex stimulus processing emphasizing the concept of dynamic localization. (C) 2008 Published by Elsevier B.V

Altered gamma and theta oscillations during multistable perception in schizophrenia

Objective: Coherent object perception in patients with schizophrenia is known to be impaired. Oscillatory brain dynamics constitute a fundamental mechanism for the coordinated communication of neural circuits. Such dynamics have been proposed to reflect impaired spatio-temporal integration of sensory and cognitive processes during object perception in schizophrenia