Neural measures associated with configural threat acquisition

Contextual threat learning reflects two often competing processes: configural and elemental learning. Configural threat learning is a hippocampal-dependent process of forming a conjunctive representation of a context through binding of several multi-modal elements. In contrast, elemental threat-learning is governed by the amygdala and involves forming associative relationships between individual features within the context. Contextual learning tasks in humans however, rarely probe if a learned fear response is truly due to configural learning vs. simple elemental associations. The aim of the current study was to probe both constructs separately to enable a more refined interpretation of configural vs. elemental threat learning performance and mediating circuits. Subjects (n = 25) performed both a novel feature-identical contextual threat conditioning task and a discrete cue threat acquisition task while undergoing functional magnetic resonance imaging. Results demonstrated increased hippocampus activity for the threat configuration compared to the safe configuration. This pattern was not observed in the amygdala. In contrast, elemental threat learning was associated with increased amygdala, but not hippocampus activity. Whole-brain analyses revealed that both configural and elemental threat acquisition share neural circuitry related to fear expression. These results provide support for the importance of the hippocampus specifically in configural threat acquisition and fear expression.