Coarse threat images reveal theta oscillations in the amygdala: a magnetoencephalography study

Abstract

Neurocognitive models propose a specialised neural system for processing threat-related information, in which the amygdala plays a key role in the analysis of threat cues. fMRI research indicates that the amygdala is sensitive to coarse visual threat-relevant information, e.g., low spatial frequency (LSF) fearful faces. However, fMRI cannot determine the temporal or spectral characteristics of neural responses. Consequently, we used MEG to explore spatiotemporal patterns of activity in amygdala and cortical regions using blurry (LSF) and normal angry, fearful and neutral faces. Results demonstrated differences in amygdala activity between LSF threat-related and LSF neutral faces (50-250 ms after face onset). These differences were evident in the theta range (4-8 Hz) and accompanied by power changes in visual and frontal regions. Results support the view that the amygdala is involved in the early processing of coarse threat-related information and that theta is important in integrating activity within emotion processing networks