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Abstract:
Using functional Magnetic Resonance Imaging (fMRI) to study
brain activity related to the experience of emotion presents unique
challenges to neuroscientists. This is partly because fMRI data
analysis is typically performed by comparing signal changes at each
voxel with a reference waveform representing the time-course of
stimulus presentation. Brain activity in response to emotional
stimuli cannot be detected by this method if the response does not
significantly diminish before the subsequent presentation of
neutral stimuli. This study was conducted to better understand the
time-course of the emotional response to aversive pictures. A group
of N=20 women were presented with a total of 64 aversive, neutral,
and scrambled pictures at a rate of 1 per 4 seconds. All pictures
were presented on a computer in alternating blocks of aversive and
neutral pictures (similar to the design of an fMRI imaging
experiment) but with blocks of scrambled images after each picture
block. The subject responded to each picture by verbally rating the
intensity of her negative emotional state. Skin conductance
responses were also recorded. The duration of the emotional
response was determined from the subjective ratings and skin
conductance data collected during the blocks of scrambled pictures.
Preliminary results will be discussed in terms of relevance to fMRI
studies of emotion.
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