Time-Dependent Amygdala Activation During Anticipation of Pain
Introduction
The allocation of attentional resources is thought to modulate the processing of emotional information in the amygdala. The role of time has not been addressed in current models.
Section snippets
Methods
Two sets of healthy subjects completed two different functional magnetic resonance imaging (fMRI) studies to examine activation in the amygdala during cued anticipation of a painful stimulus while subjects were engaged in a continuous performance task of fixed (Study 1) and parametrically modulated (Study 2) duration. In both studies different colors explicitly signaled impending painful stimuli.
Results
In Study 1 we found that activation of the amygdala bilaterally was attenuated during the task, but inversely with subjects’ reaction time, rather than directly. Furthermore, amygdala activation was linearly proportional to the remaining anticipation time. These findings suggest a time-dependent model of emotional processing but do not distinguish between attention-dependent and attention-independent processes. In Study 2 we confirmed attenuation of the amygdala bilaterally by the task as well
Conclusions
Our findings from the two separate brain-imaging studies confirm that behavioral distraction due to a continuous performance task attenuates bilateral amygdala activation during anticipation of a painfully hot stimulus. Interestingly, we found that this attenuation is inversely proportional with the degree of engagement in the task and that anticipatory time itself, independent of attentional engagement, drives bilateral amygdala activation. These results suggest a novel mechanism that might