Event-related oscillations to affective stimuli: heritability, linkage and relationship to externalizing disorders

Abstract

Event-related oscillations (EROs) are heritable electrophysiological measures associated with cognitive activity and have been shown to be particularly informative for the genetic analysis of substance dependence and other psychiatric disorders. In the present study associations between the cortical event-related oscillations (EROs) elicited by affective stimuli, and the diagnosis of ASPD or CD (ASPD/CD) were investigated, and heritability and linkage analyses conducted in 662 individuals residing in an American Indian community. Results from this study found that participants with ASPD/CD showed increased alpha ERO energy in centro-parietal leads in the 0-250 ms time window in response to all three emotional expressions (sad, neutral and happy faces). Participants with ASPD/CD also showed increased alpha ERO energy in centro-parietal leads in the 400-700 ms time window in response to happy and neutral faces. Variance components analysis suggested a significant familial component to each of the described ERO phenotypes. Although a follow-up genome-wide linkage analysis failed to detect significant evidence of genetic linkage for any of these phenotypes, centro-parietal alpha energy in response to happy faces showed suggestive evidence of linkage to chromosome 1p36.31 (LOD = 2.40), in an area found in previous studies to be associated with externalizing phenotypes. Findings from this study suggest greater activation of neural circuits required to perform a facial recognition task in participants with ASPD/CD. The observed increase in alpha ERO energy may represent a heritable endophenotype associated with select externalizing disorders in this population.

Figure 1

Time-frequency responses of evoked alpha band energy distribution to sad, neutral and happy faces in participants without ASPD/CD (A, B, C) and with ASPD/CD (D, E, F) participants at the Pz electrode position. Time-frequency ROI windows (in white squares) shown were 0 – 250 ms (a) and 400 – 700 ms (b) The inset shows representative ERP grand averages from participants without ASPD/CD (left) and with ASPD/CD (right) groups in response to sad, neutral and happy faces.

Figure 2

Mean amplitude values of ERO energy for alpha bands in response to sad, neutral and happy faces in centro-parietal leads. (A). ASPD/CD participants showed an increase in alpha ERO energy in the 0 – 250 ms time window in response to sad, neutral and happy faces. (B). ASPD/CD participants showed an increase in alpha ERO energy in the 400 – 700 ms time window in response to neutral and happy, but not sad faces. Greater alpha ERO energy was found in response to happy faces than to sad and neutral faces in participants without ASPD/CD participants. Alpha ERO energy was greater in response to neutral faces than to sad faces in participants without ASPD/CD. Greater alpha ERO energy was found in response to happy faces than to sad faces in ASPD/CD participants.* Significant differences between participants with and without ASPD/CD; a Significant differences between sad and neutral faces; b Significant differences between sad and happy faces; c Significant differences between neutral and happy faces (p < 0.004).