The Phenomenology of Offline Perception: Multisensory Profiles of Voluntary Mental Imagery and Dream Imagery.

Both voluntary mental imagery and dream imagery are multisensory representations that occur without external stimuli, classifiable as offline perceptions. In 226 participants, correlations between sensory modalities within each state (waking or dreaming) were significantly stronger than across states, suggesting two distinct neural networks. However, the link between vividness of voluntary mental imagery and dream imagery grew stronger with higher dream recall frequency and lucid dreaming, indicating greater network overlap when metacognition is elevated. Emotional and visual imagery were more vivid in dreams, reflecting dreams' immersive nature and visual dominance across wake and sleep.

Study at a glance

Abstract

Both voluntary mental imagery and dream imagery involve multisensory representations without externally present stimuli that can be categorized as offline perceptions. Due to common mechanisms, correlations between multisensory dream imagery profiles and multisensory voluntary mental imagery profiles were hypothesized. In a sample of 226 participants, correlations within the respective state of consciousness were significantly bigger than across, favouring two distinct networks. However, the association between the vividness of voluntary mental imagery and vividness of dream imagery was moderated by the frequency of dream recall and lucid dreaming, suggesting that both networks become increasingly similar when higher metacognition is involved. Additionally, the vividness of emotional and visual imagery was significantly higher for dream imagery than for voluntary mental imagery, reflecting the immersive nature of dreams and the continuity of visual dominance while being awake and asleep. In contrast, the vividness of auditory, olfactory, gustatory, and tactile imagery was higher for voluntary mental imagery, probably due to higher cognitive control while being awake. Most results were replicated four weeks later, weakening the notion of state influences. Overall, our results indicate similarities between dream imagery and voluntary mental imagery that justify a common classification as offline perception, but also highlight important differences.