Oneiric synesthesia: Preliminary evidence for the occurrence of synesthetic-like experiences during sleep-inertia

Daniel Reznik, Limor Gertner-Saad, Hagit Even-Furst, Avishai Henik, Eyal Ben Mair, Dalia Shechter-Amir, Nirit Soffer-Dudek

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Synesthesia is a condition that involves atypical binding between two seemingly independent sensory modalities. The neural origin of this condition is controversial: Although some claim that synesthesia originates from stable anatomical irregularities, others suggest that its occurrence relies on functional properties of brain dynamics. In the current study, we aimed to better understand synesthesia by comparing it with another state in which perception is dramatically altered, namely, sleeping and dreaming. Specifically, on the phenomenological level, both synesthesia and sleeping mentation are characterized by hyper-associated mental images. Therefore, in the current study we tested whether nonsynesthetic subjects would report synesthetic-like experiences upon awakening (i.e., during sleep-inertia). In 2 studies, healthy subjects were asked to complete a questionnaire in which they rated the extent of their agreement with statements representing synesthetes' cross-sensory experience (e.g., "musical tones trigger the experience of colors"), along with other (masking) statements. Subjects in the experimental group completed the questionnaire during sleep-inertia, whereas subjects in the control group completed the questionnaire during wakefulness. We found that subjects who completed the questionnaire upon awakening from sleep reported greater agreement with the cross-modal statements compared with wakeful controls, whereas no difference was found for the masking statements. Our findings support the functional, rather than the anatomical, view of synesthesia; specifically, synesthetic experience might be the result of reduced cortical inhibition. Moreover, the current study suggests an exciting new research direction, that is, exploring possible similarities between sleeping and synesthetic brains.

Original languageEnglish
Pages (from-to)374-383
Number of pages10
JournalPsychology of Consciousness: Theory Research, and Practice
Issue number4
StatePublished - 1 Dec 2018


  • Hyper-association
  • Multisensory perception
  • Sleep
  • Sleep-inertia
  • Synesthesia

ASJC Scopus subject areas

  • Social Psychology
  • Neuropsychology and Physiological Psychology
  • Experimental and Cognitive Psychology
  • Clinical Psychology


Dive into the research topics of 'Oneiric synesthesia: Preliminary evidence for the occurrence of synesthetic-like experiences during sleep-inertia'. Together they form a unique fingerprint.

Cite this