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Abstract:
Several studies show that high-frequency Transcranial
Magnetic Stimulation (TMS) of the prefrontal cortex is capable of
inducing lateralized effects on mood (i.e. sadness, anxiety and
happiness). In the present experiment, low-frequency TMS (0.6 Hz)
was used to examine if low-frequency stimulation could also
influence mood. The left and right hemispheres of 4 subjects were
stimulated on separate days for 15 minutes at 130% of the Motor
Threshold (MT) with a water-cooled 8-shaped coil, manufactured by
Cadwell. Mood was measured using the Profile of Mood States (POMS),
before stimulation and 10 minutes after. In addition, selective
attention for angry faces was assessed using an emotional Stroop
task. Mood questionnaire data indicated that left, as compared to
right prefrontal cortex stimulation, resulted in a significant
decrease in scores on the tension-anxiety scale. The emotional
Stroop task showed that right, as compared to left, prefrontal
stimulation resulted in subjects' speeding up when color-naming
angry in comparison to neutral faces (i.e. they avoided the
processing of threat). These results support Davidson's (1990)
theory of lateralization of positive and negative affect in terms
of approach and avoidance.
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