کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6263334 | 1613862 | 2014 | 12 صفحه PDF | دانلود رایگان |
- The aim of the study is to understand the effect of experimental design on IAPS pictures.
- Beta and gamma oscillatory responses were analyzed during perception of IAPS pictures.
- Increased beta/gamma responses were found for unpleasant pictures during block design.
- Unpleasant pictures did not elicit higher beta /gamma responses in the random design.
Several studies reveal that unpleasant pictures elicit higher beta and gamma responses than pleasant and/or neutral pictures; however, the effect of stimulation design (block or random) has not been studied before. The aim of the study is to analyze the common and distinct parameters of affective picture perception in block and random designs by means of analysis of high frequency oscillatory dynamics (beta and gamma). EEG of 22 healthy subjects was recorded at 32 locations. The participants passively viewed 120 emotional pictures (10Ã4 unpleasant, 10Ã4 pleasant, 10Ã4 neutral) in block and random designs. The phase-locking and power of event related beta (14-28Â Hz) and gamma (29-48Â Hz) oscillations were analyzed for two different time windows (0-200Â ms/200-400Â ms). Statistical analysis showed that in the 0-200Â ms time window, during the block design, unpleasant stimulation elicited higher beta phase-locking and beta power than the pleasant and neutral stimulation (p<0.05). In the 200-400Â ms time window, during the block design, over occipital electrodes unpleasant stimulation elicited higher gamma response power than the pleasant stimulation and neutral stimulation (p<0.05). Unpleasant stimulation did not elicit higher beta or gamma responses in the random design. The present study showed that experimental design highly influences the perception of IAPS pictures. Unpleasant stimulation elicited higher event related beta and gamma phase-locking and power only in block design but not in random design. It seems that longer blocks of aversive pictures affect the brain more than the rapid observation of these pictures.
Journal: Brain Research - Volume 1577, 19 August 2014, Pages 45-56