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The effect of threat on novelty evoked amygdala responses.

Balderston NL, Schultz DH, Helmstetter FJ - PLoS ONE (2013)

Bottom Line: Surprisingly, we found that novel images of snakes and flowers evoke more amygdala activity than repeated images of snakes and flowers.Our results further confirm the robustness of the novelty evoked amygdala responses, even when compared with effects more traditionally associated with the amygdala.In addition, our results suggest that threatening stimuli may prime the amygdala to respond to other types of stimuli as well.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America.

ABSTRACT
A number of recent papers have suggested that the amygdala plays a role in the brain's novelty detection circuit. In a recent study, we showed that this role may be specific to certain classes of biologically-relevant stimuli, such as human faces. The purpose of the present experiment was to determine whether other biologically-relevant stimuli also evoke novelty specific amygdala responses. To test this idea, we presented novel and repeated images of snakes and flowers while measuring BOLD. Surprisingly, we found that novel images of snakes and flowers evoke more amygdala activity than repeated images of snakes and flowers. Our results further confirm the robustness of the novelty evoked amygdala responses, even when compared with effects more traditionally associated with the amygdala. In addition, our results suggest that threatening stimuli may prime the amygdala to respond to other types of stimuli as well.

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Related in: MedlinePlus

Novel snakes and novel flowers drive BOLD activity in the amygdala and hippocampus.(a,c) Line graphs represent BOLD timecourse in the amygdala (a) and hippocampus (c). (b,d) Bar graphs represent the percent signal change in the amygdala (b) and hippocampus (d) during the last two seconds of the stimulus period. All data points represent mean±SEM. (NS = novel snake, RS = repeated snake, NF = novel flower, RF = repeated flower).
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pone-0063220-g003: Novel snakes and novel flowers drive BOLD activity in the amygdala and hippocampus.(a,c) Line graphs represent BOLD timecourse in the amygdala (a) and hippocampus (c). (b,d) Bar graphs represent the percent signal change in the amygdala (b) and hippocampus (d) during the last two seconds of the stimulus period. All data points represent mean±SEM. (NS = novel snake, RS = repeated snake, NF = novel flower, RF = repeated flower).

Mentions: Contrary to our hypothesis we did not observe a novelty × stimulus type interaction. Instead we found that snakes and flowers evoked more amygdala activity when novel than when repeated (F(1,17) = 9.155; p = 0.008; See Figure 3a,b). Although we chose to use an anatomical ROI approach to remain consistent with our previous study, results from the whole brain analysis also show significant clusters of activation within the amygdala. Snakes and flowers also evoked more hippocampal activity when novel than when repeated (F(1,17) = 15.690; p = 0.001; See Figure 3c,d), consistent with the hippocampal novelty detection hypothesis. In contrast, the effect of threat on amygdala and hippocampus responses was only a trend. Snakes evoked only marginally more amygdala (F(1,17) = 3.393; p = 0.083) and hippocampal (F(1,17) = 3.829; p = 0.067) activity than flowers. In the hippocampus, this effect seemed to be larger in the left hemisphere (F(1,17) = 4.822; p = 0.042), but there were no other significant effects (ps <0.1).


The effect of threat on novelty evoked amygdala responses.

Balderston NL, Schultz DH, Helmstetter FJ - PLoS ONE (2013)

Novel snakes and novel flowers drive BOLD activity in the amygdala and hippocampus.(a,c) Line graphs represent BOLD timecourse in the amygdala (a) and hippocampus (c). (b,d) Bar graphs represent the percent signal change in the amygdala (b) and hippocampus (d) during the last two seconds of the stimulus period. All data points represent mean±SEM. (NS = novel snake, RS = repeated snake, NF = novel flower, RF = repeated flower).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643910&req=5

pone-0063220-g003: Novel snakes and novel flowers drive BOLD activity in the amygdala and hippocampus.(a,c) Line graphs represent BOLD timecourse in the amygdala (a) and hippocampus (c). (b,d) Bar graphs represent the percent signal change in the amygdala (b) and hippocampus (d) during the last two seconds of the stimulus period. All data points represent mean±SEM. (NS = novel snake, RS = repeated snake, NF = novel flower, RF = repeated flower).
Mentions: Contrary to our hypothesis we did not observe a novelty × stimulus type interaction. Instead we found that snakes and flowers evoked more amygdala activity when novel than when repeated (F(1,17) = 9.155; p = 0.008; See Figure 3a,b). Although we chose to use an anatomical ROI approach to remain consistent with our previous study, results from the whole brain analysis also show significant clusters of activation within the amygdala. Snakes and flowers also evoked more hippocampal activity when novel than when repeated (F(1,17) = 15.690; p = 0.001; See Figure 3c,d), consistent with the hippocampal novelty detection hypothesis. In contrast, the effect of threat on amygdala and hippocampus responses was only a trend. Snakes evoked only marginally more amygdala (F(1,17) = 3.393; p = 0.083) and hippocampal (F(1,17) = 3.829; p = 0.067) activity than flowers. In the hippocampus, this effect seemed to be larger in the left hemisphere (F(1,17) = 4.822; p = 0.042), but there were no other significant effects (ps <0.1).

Bottom Line: Surprisingly, we found that novel images of snakes and flowers evoke more amygdala activity than repeated images of snakes and flowers.Our results further confirm the robustness of the novelty evoked amygdala responses, even when compared with effects more traditionally associated with the amygdala.In addition, our results suggest that threatening stimuli may prime the amygdala to respond to other types of stimuli as well.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America.

ABSTRACT
A number of recent papers have suggested that the amygdala plays a role in the brain's novelty detection circuit. In a recent study, we showed that this role may be specific to certain classes of biologically-relevant stimuli, such as human faces. The purpose of the present experiment was to determine whether other biologically-relevant stimuli also evoke novelty specific amygdala responses. To test this idea, we presented novel and repeated images of snakes and flowers while measuring BOLD. Surprisingly, we found that novel images of snakes and flowers evoke more amygdala activity than repeated images of snakes and flowers. Our results further confirm the robustness of the novelty evoked amygdala responses, even when compared with effects more traditionally associated with the amygdala. In addition, our results suggest that threatening stimuli may prime the amygdala to respond to other types of stimuli as well.

Show MeSH
Related in: MedlinePlus