Abstract
Studies have reported increased activity in motor cortical areas during emotional processing. Additionally, exposure to unpleasant emotional images, as compared with pleasant and neutral images, has been shown to accelerate premotor reaction times (PRT) of upper limb ballistic extension movements. In the present study, we examined the effects of an auditory startling stimulus during exposure to unpleasant, as compared with pleasant, neutral and blank images. An auditory startling stimulus has been shown to accelerate simple reaction times to latencies (<65 ms) too fast to invoke cortical activity, leading to the subcortical storage and triggering hypothesis (Valls-Solé et al., 1999; Carlsen et al., 2004). Thus, we hypothesized that any PRT differences due to emotion would be absent during startle trials. Analyses revealed no difference in PRTs for unpleasant, neutral and pleasant images for control tone (82 dB) trials, but all three categories were significantly faster than trials when a blank screen was present, a result we attributed to attention mechanisms. Following startle tone (124 dB) trials, there were no differences in PRT for all four conditions (unpleasant, neutral, pleasant and blank); however, PRTs were accelerated compared to control tone trials. These results suggest that differences due to cortical activities are not present when a startling stimulus is used.Acknowledgments: This research was supported by NSERC