With the power of the inner eyes: The Late Positive Potential during mental time travel through positive and negative experiences. An event-related potential study.

Mental time travel utilizes mental imagery to recollect past experiences and to prospect hypothetical future events. This elicits anticipatory affect responses that are pivotal to motivate goal-directed behavior towards pleasurable and away from threatening experiences. However, the temporal dynamics of neural, physiological and affective processing of mental time travel remain elusive. Here, we aimed to examine the Late Positive Potential (LPP), skin conductance responses (SCR) and behavioral affect ratings in response to mental time travel through emotionally salient experiences. Forty-eight participants (52% females) viewed 16 neutral, positive, and negative stimuli from the International Affective Picture System (‘encoding task’). Participants then imagined each stimulus as vividly as possible (‘recall task’) and experiencing each situation after leaving the laboratory (‘prospection task’). Results showed significantly potentiated electrocortical activity in the LPP in response to recalling negative and prospecting positive stimuli. Behavioral ratings also showed a significant potentiation of self-reported positive and negative affect and arousal in response to both recalling and prospecting positive as well as negative stimuli. SCR amplitudes were not significantly associated with recalling or prospecting these experiences. Our findings suggest that the retrieval and prospection of emotionally salient experiences are associated with neural anticipatory responses in the LPP. This could reflect a neural mechanism that facilitates affective responses to mental representations of emotional stimuli, thereby guiding goal-directed behavior. Future studies should compare clinical to non-clinical groups in this context to illuminate the mechanisms of aberrant mental time travel and emotional disturbances in psychopathology.