Rapid amygdala responses during trace fear conditioning without awareness.
PLoS One January 1, 2014 Nicholas L Balderston, Douglas H Schultz, Sylvain Baillet et al.
People can learn to associate a face with a later shock even when they are unaware of seeing the face, challenging the view that conscious awareness is necessary for trace fear conditioning. Using magnetoencephalography (MEG) to record amygdala activity, the authors observed rapid neural responses (around 170-200 milliseconds) during the interval between the unperceived face and the shock. These results suggest that unperceived faces can serve as signals for impending threat and that automatic amygdala activation contributes to this learning. The study also describes a novel MEG methodology for investigating subcortical structures.