Instantaneous radiated power of brain activity: application to prepulse inhibition and facilitation for body dysmorphic disorder

Abstract

Background Global measures of neuronal activity embrace the advantage of a univariate, holistic and unique description of brain activity, reducing the spatial dimensions of electroencephalography (EEG) analysis at the cost of lower precision in localizing effects. In this work, the instantaneous radiated power (IRP) is proposed as a new whole-brain descriptor, reflecting the cortical activity from an exclusively electromagnetic perspective. Considering that the brain consists of multiple elementary dipoles, the whole-brain IRP takes into account the radiational contribution of all cortical sources. Unlike conventional EEG analyses that evaluate a large number of scalp or source locations, IRP reflects a whole-brain, event-related measure and forces the analysis to focus on a single time-series, thus efficiently reducing the EEG spatial dimensions and multiple comparisons. Results To apply the developed methodology in real EEG data, two groups (25 controls vs 30 body dysmorphic disorder, BDD, patients) were matched for age and sex and tested in a prepulse inhibition (PPI) and facilitation (PPF) paradigm. Two global brain descriptors were extracted for between-groups and between-conditions comparison purposes, namely the global field power (GFP) and the whole-brain IRP. Results showed that IRP can replicate the expected condition differences (with PPF being greater than PPI responses), exhibiting also reduced levels in BDD compared to control group overall. There were also similar outcomes using GFP and IRP, suggesting consistency between the two measures. Finally, regression analysis showed that the PPI-related IRP (during N100 time-window) is negatively correlated with BDD psychometric scores. Conclusions Investigating the brain activity with IRP significantly reduces the data dimensionality, giving insights about global brain synchronization and strength. We conclude that IRP can replicate the existing evidence regarding sensorimotor gating effects, revealing also group electrophysiological alterations. Finally, electrophysiological IRP responses exhibited correlations with BDD psychometrics, potentially useful as supplementary tool in BDD symptomatology.

Deciding on Optical Illusions: Reduced Alpha Power in Body Dysmorphic Disorder

“…Specifically, increased excitability is associated with low alpha power. BDD patients have impaired attentional processes, potentially associated with a hyperactivity of the functional circuits involved in the selective attention [36,37]. Therefore, our findings may indicate an over-attention of BDD during illusory perception.…”

Deciding on Optical Illusions: Reduced Alpha Power in Body Dysmorphic Disorder

“…Specifically, increased excitability is associated with low alpha power. BDD patients have impaired attentional processes, potentially associated with a hyperactivity of the functional circuits involved in the selective attention [ 46 , 47 ]. Therefore, our findings may indicate an over-attention of BDD patients during illusory perception.…”

Evaluating the Modulation of the Acoustic Startle Reflex in Children and Adolescents via Vertical EOG and EEG: Sex, Age, and Behavioral Effects

“…Three dominant poststartle (early) ERP components were observed from the collapsed ERPs (i.e., grand-averages across subjects and conditions), namely, the positive-going P50 (20–60 ms, frontocental), the negative-going N100 (61–110 ms, central), and the positive-going P200 (111–230 ms, centroparietal) components. Allof these components have been systematically observed in PPI/PPF paradigms ( Patterson et al, 2008 ; De Pascalis et al, 2013 ; Giannopoulos et al, 2021a ,b), mainly associated with sensorimotor gating, attentional allocation, and orientation cognitive processes in responses to the ASR. For visual inspection purposes, Figure 3 illustrates the collapsed ERPs averaged across three regions of interest (ROIs), where each component was primarily distributed: ROI for P50 = {AFZ, FZ, F3/F4, FCZ, FC3/FC4}, ROI for N100 = {FCZ, FC3/FC4, CZ, C3/C4, CPZ, CP3/CP4}, ROI for P200 = {FCZ, CZ, C3/C4, CPZ}.…”