NIH Research Festival
Forming memory representations is commonly impaired in anxiety patients, who often overgeneralize details of fearful situations to non-fearful situations. Behavioral pattern separation (BPS), the ability to discriminate among items based on subtle differences, could be used to examine possible mechanisms underlying fear overgeneralization. This study explored changes in neural activity as participants performed BPS under periods of threat and safety. Subjects viewed images of household items at encoding and retrieval in blocks of safety and threat during fMRI. In retrieval, participants judged whether the items presented were new, old (identical during encoding/retrieval), or altered (rotated slightly during retrieval). We analyzed BPS and brain activity in retrieval as a function of encoding block (threat or safe), retrieval block (threat or safe), and image type (old or altered). Threat during retrieval increased activity in the left anterior insula and the dorsal anterior cingulate cortex (dACC), across all stimuli. Threat also increased activation in the right dorsolateral prefrontal cortex (dlPFC), to altered (but not old) images. No behavioral differences were found across conditions. Activation of the insula and dACC as a function of threat replicates previous work suggesting these regions play a vital role in emotional expression. Activation in the dlPFC, an area important for cognitive control, may reflect increased cognitive control processes needed to perform a difficult task during periods of elevated anxiety. Previous research has also highlighted impairment in the dlPFC in anxious patients. Although we studied healthy adults, these results may help explain fear overgeneralization in anxiety disorders.
Scientific Focus Area: Neuroscience
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