Right hemisphere neural activations in the recall of waking fantasies and of dreams

Abstract

SUMMARYThe story-like organization of dreams is characterized by a pervasive bizarreness of events and actions that resembles psychotic thought, and largely exceeds that observed in normal waking fantasies. Little is known about the neural correlates of the confabulatory narrative construction of dreams. In this study, dreams, fantasies elicited by ambiguous pictorial stimuli, and non-imaginative first-and third-person narratives from healthy participants were recorded, and were then studied for brain blood oxygen level-dependent functional magnetic resonance imaging on a 3.0-Tesla scanner while listening to their own narrative reports and attempting a retrieval of the corresponding experience. In respect to nonbizarre reports of daytime activities, the script-driven recall of dreams and fantasies differentially activated a right hemisphere network including areas in the inferior frontal gyrus, and superior and middle temporal gyrus. Neural responses were significantly greater for fantasies than for dreams in all regions, and inversely proportional to the degree of bizarreness observed in narrative reports. The inferior frontal gyrus, superior and middle temporal gyrus have been implicated in the semantic activation, integration and selection needed to build a coherent story representation and to resolve semantic ambiguities; in deductive and inferential reasoning; in self-and other-perspective taking, theory of mind, moral and autobiographical reasoning. Their degree of activation could parallel the level of logical robustness or inconsistency experienced when integrating information and mental representations in the process of building fantasy and dream narratives.

Déjà-rêvé: Prior dreams induced by direct electrical brain stimulation

“…A majority of right EBS-inducing déjà-rêvé in our database could also suggest a potential lateralizing value of déjà-rêvé. But while this is consistent with fMRI results demonstrating that the recall of dreams and fantasies differentially activated a right hemisphere network [ 36 ], more data are needed to assess the strength of this hypothesis.…”

“…We also found a clear majority of right EBS in our database. We cannot draw conclusions from this because there are too few observations; however, right hemisphere activation during dream recall has already been suggested [ [33] , [34] , [35] , [36] , [37] ]. For example, the right hemisphere may be linked to dream materials and the left hemisphere to dream encoding and interpretation [ 34 ].…”

Dreaming the unrepressed unconscious and beyond: repression <em>vs</em> dissociation in the oneiric functioning of severe patients

“…This involvement of limbic structures is further supported by findings that relate bizarreness in dream that is positively associated with volumes of hippocampus and negatively with volume in left amygdala (De Gennaro et al, 2011). The predominance of right brain activation related to dream and fantasies is further supported by a recent study (Benedetti et al, 2015) showing the involvement of right inferior frontal gyrus, right superior temporal gyrus and right middle temporal gyrus when compared to non-imaginative reports conditions. Other studies in REM sleep stages show an increased activation and connectivity in medial temporal regions like the hippocampus, a key hub for encoding and retrieving memory (Burgess, Maguire, & O'Keefe, 2002).…”

Classification of Distinct Vividness of Auditory Imagery in the Brain Based on Support Vector Machine

“…It could be responsible to transform multiple perceptual information into anteromedial temporal lobe [14]. It also showed significant effect when the auditory imagery was performed and the dream or fantasies were conducted [15].…”