Functional magnetic resonance imaging of temporally distinct responses to emotional facial expressions

Abstract

Understanding the temporal dynamics of brain function contributes to models of learning and memory as well as the processing of emotions and habituation. In this article, we present a novel analysis technique to investigate spatiotemporal patterns of activation in response to blocked presentations of emotional stimuli. We modeled three temporal response functions (TRFs), which were maximally sensitive to the onset, early or sustained temporal component of a given block type. This analysis technique was applied to a data set of 29 subjects who underwent functional magnetic resonance imaging while responding to fearful, happy, and sad facial expressions. We identified brain regions that uniquely fit each of the three TRFs for each emotional condition and compared the results to the standard approach, which was based on the canonical hemodynamic response function. We found that voxels within the precuneus fit the onset TRF but did not fit the early or the sustained TRF in all the emotional conditions. On the other hand, voxels within the amygdala fit the sustained TRF, but not the onset or early TRF, during presentation of fearful stimuli, suggesting a spatiotemporal dissociation between these structures. This technique provides researchers with an additional tool in order to investigate the temporal dynamics of neural circuits.

Acknowledgements

The research reported in this article served to fulfill the dissertation requirements of Brian W. Haas in the Department of Psychology at Stony Brook University. The authors would like thank J. Ferri for excellent assistance in collecting fMRI data. This research was supported by the National Science Foundation, NSF Grant No. 0224221, to TC and by the Stony Brook University Retirees’ Dissertation Fellowship awarded to BWH.