Spatiotemporal Context-Generalization of Object Category Representations during Fear Conditioning.

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Generalization of emotional arousing experiences to other contexts is adaptive. Fear related disorders are often characterized by excessive generalization, indicating an impaired integration of cue and context information. Neocortical representations of emotional experiences show increased spontaneous reactivations during post-learning rest, which lead to better memory. However, it remains unclear whether context spontaneously reactivates these neocortical representations of emotional experiences during rest and how this affects generalization. We hypothesize that increased context generalization is associated with heightened activity of neocortical representations of emotional experiences in a safe context. To test this, participants underwent a categorical localizer paradigm, followed by a categorical differential delay cue/contextual fear conditioning paradigm. We used a virtual reality environment that contained a threat and safe context to acquire context specific activity patterns of CS+ and CS- object category representations from blood-oxygen-level dependent functional magnetic resonance imaging (BOLD fMRI). An exemplar of the CS + category was paired with a mild electrical stimulation, but only when it was presented in a threat context. We found differential skin conductance responses (SCR) in the threat context, indicating successful conditioning, but also in the safe context, indicating context generalization. Using representational similarity analyses we found increased differential representations in the threat context compared to the safe context. This was driven by reduced representation of the CS- in the threat context. Critically, we found that the more participants inhibited CS- representations in the threat context, the more they exhibited fear generalization, measured with SCR. In conclusion, our data show that suppression of neutral objects underlies individual differences in fear generalization.
Faculteit der Sociale Wetenschappen