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.
People with Aphantasia, initially characterized as having a deficit in visual imagination, often also report lacking imagined sensations in other modalities such as sound, taste, smell, touch, and body movement. These patterns of imaginative inability vary individually. Many Aphantasics report visual dreams, suggesting the deficit might be specific to volitional waking imagined sensations. This study assessed the multisensory profiles of Aphantasics' dreams and found a typical correspondence between reported multisensory dream contents and volitional waking imagined experiences, though with considerable heterogeneity. Some Aphantasics show tight associations between dream and waking imagined sensations, while others show little or no correspondence, challenging researchers to explain these diverse outcomes.