Effect of anxiety on behavioural pattern separation in humans

ABSTRACT

Behavioural pattern separation (BPS), the ability to distinguish among similar stimuli based on subtle physical differences, has been used to study the mechanism underlying stimulus generalisation. Fear overgeneralisation is often observed in individuals with posttraumatic stress disorder and other anxiety disorders. However, the relationship between anxiety and BPS remains unclear. The purpose of this study was to determine the effect of anxiety (threat of shock) on BPS, which was assessed across separate encoding and retrieval sessions. Images were encoded/retrieved during blocks of threat or safety in a 2 × 2 factorial design. During retrieval, participants indicated whether images were new, old, or altered. Better accuracy was observed for altered images encoded during periods of threat compared to safety, but only if those images were also retrieved during periods of safety. These results suggest that overgeneralisation in anxiety may be due to altered pattern separation.

KEYWORDS:

• Pattern separation
• threat of shock
• anxiety
• startle
• generalisation

ORCID

Nicholas L. Balderston http://orcid.org/0000-0002-8565-1544

Additional information

Funding

This research was supported by the Intramural Research Program of the National Institute of Mental Health [grant number MH002798] (Protocol 01-M-0185).