Abstract The language people use to describe their inner experiences arising during sleep and wakefulness provides a window into the mind. Dreams and unguided waking thought, here referred to as mind wandering, are thought to reflect unique individual differences and mental health. Here we use graph theory to analyse a large dataset of dream (n = 1434) and mind wandering (n = 1619) reports from...
Scientific ReportsMarch 13, 2026Daniel Soares Brandão, Rafael N. B. Scott, Ernesto Soares et al.
Every studied animal species exhibits some form of sleep, a state evolved under the sustained influence of prey and predator behaviors. Dreams have been proposed to have evolved as offline mental simulations able to warn against impending threats from the environment, such as predators. To assess how the ecological roles of prey and predator interact with sleep and dreaming, we used a...
Language disorganization is a hallmark of psychosis which has traditionally been assessed through clinical interviews and standardized scales. Recent advances in Natural Language Processing (NLP) and graph theory provide innovative, objective methodologies to analyze language production in psychosis. In particular, dream reports, as a unique form of narrative, offer a valuable lens through...
The intricate interplay between visual perception and emotion determines how waking experience influences mentation through a 'day residue' at once conspicuous yet hard to predict. Here we set out to map the neural sources associated with the visuo-affective processing of the 'day residue' during hypnagogic sleep. To this end, we assessed 28 healthy participants on a combined nap protocol with...
Language has been explored as a window into the mind. Psychedelics, known to affect perception and cognition, seem to change language, but a systematic, time-dependent exploration is lacking. Therefore, we aimed at mapping the psychedelic effects on language over the time course of the acute and sub-acute effects in an explorative manner. For this, 24 healthy volunteers (age [mean±SD, range]:...
The 'day residue' - the presence of waking memories into dreams - is a century-old concept that remains controversial in neuroscience. Even at the psychological level, it remains unclear how waking imagery cedes into dreams. Are visual and affective residues enhanced, modified, or erased at sleep onset? Are they linked, or dissociated? What are the neural correlates of these transformations? To...
Stream of thought describes the nature of the mind when it is freely roaming, a mental state that is continuous and highly dynamic as in mind-wandering or free association. Classic serotonergic psychedelics are known to profoundly impact perception, cognition and language, yet their influence on the stream of thought remains largely unexplored. To elucidate the effects of LSD on the stream of...
The current global threat brought on by the Covid-19 pandemic has led to widespread social isolation, posing new challenges in dealing with metal suffering related to social distancing, and in quickly learning new social habits intended to prevent contagion. Neuroscience and psychology agree that dreaming helps people to cope with negative emotions and to learn from experience, but can dreaming...
Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural organization of dream reports is lacking, and traditional measures that distinguish REM and non-REM dreaming may be confounded by report length. This problem...
Neuroscience and psychology agree that dreaming helps to cope with negative emotions and learn from experience. The current global threat related to the COVID-19 pandemic led to widespread social isolation. Does dreaming change and/or reflect mental suffering? To address these questions, we applied natural language processing tools to study 239 dream reports from 67 individuals either before...
In the past ten years, graph theory has been widely employed in the study of natural and technological phenomena. The representation of the relationships among the units of a network allow for a quantitative analysis of its overall structure, beyond what can be understood by considering only a few units. Here we discuss the application of graph theory to psychiatric diagnosis of psychoses and...
Early psychiatry investigated dreams to understand psychopathologies. Contemporary psychiatry, which neglects dreams, has been criticized for lack of objectivity. In search of quantitative insight into the structure of psychotic speech, we investigated speech graph attributes (SGA) in patients with schizophrenia, bipolar disorder type I, and non-psychotic controls as they reported waking and...