Frontal asymmetry index in Williams syndrome: Evidence for altered emotional brain circuitry?

Abstract

Asymmetrical frontal electroencephalography (EEG) activity is associated with motivational neural systems of approach/withdrawal behaviors. Greater left frontal EEG has been linked to increased appetitive tendencies whereas increased right frontal activity is related to the activation of avoidance mechanisms. Williams syndrome (WS) is a genetic condition characterized by a highly sociable personality manifested by a propensity to approach strangers and decreased social fear. Consequently, the current study was designed to investigate the frontal cortical activity during resting state, indexed by relative alpha power, in adults with WS as compared to typically developing (TD) controls, and a subgroup of TD extraverts. Results indicated that participants with WS produced attenuated left frontal activity relative to TD peers, or TD extraverts in particular; yet, no groups differed in their degree of right frontal activity. Finally, while both TD group and the extravert subset showed trends of greater left over right frontal activity, the WS participants demonstrated opposing effect of increased right over left frontal EEG. Importantly, individuals with WS produced deviating frontal activity patterns compared to TD extraverts despite exhibiting common social-affiliative tendencies, underscoring that neural mechanisms that give rise to extraversion in WS may not function similarly to those subserving this personality trait expressed in TD.

Keywords:

• Williams syndrome
• Social neuroscience
• Extraversion
• Alpha power
• Resting EEG

We warmly thank all the participants, their families, and the Williams Syndrome Association for their generous cooperation in these studies.

Additional information

Funding

This research was supported by NICHD [033113]; The Oak Tree Philanthropic Foundation to Dr. Ursula Bellugi, NIMH [T32-MH020002] fellowship to Dr. Inna Fishman; the National Science Foundation Graduate Research Fellowship Program [00039202] as part of Rowena Ng’s training.