Friday · Oct 9 - 9:00 to 11:00

Neural correlates of dreaming and dreamlike states

Enzo Tagliazucchi

Physics Department, University of Buenos Aires

Dreaming has fascinated philosophers, psychologists and scientists for centuries.Speakers in this symposium take the approach of investigating dreaming in the tradition of consciousness research. Thus, the objective is to correlate the neural events that occur during dreams with the reported content and other aspects of the associated subjective experience. As an off-line state where consciousness and cognition can be present to a substantial degree, dreaming also offers the possibility of investigating certain aspects of human neuroscience isolated from the constant stream of percepts and affordances that characterize the waking state. Pilleriin Sikka will show how neurophysiology and phenomenology can be combined to understand affective processing and emotions during dreams. Tristan Bekinschtein will present new methodological advances to track the contents of consciousness and show their application during the hypnagogic state (the dreamlike state that appears in the transition from wakefulness to early sleep). Natalia Mota will demonstrate how natural language can be used as a window into the contents and thought processes that occur during dreams, and how this tool can be used to infer how the COVID-19 pandemic is manifest even in our dreams. Enzo Tagliazucchi will discuss the long-standing hypothesis of the psychedelic state as a dreamlike state, drawing comparisons between phenomenology, neurochemistry and the results from recent neuroscience experiments.

Dream affect: Phenomenology, neural correlates, and continuity across sleep-wake cycle

Pilleriin Sikka

Department of Cognitive Neuroscience and Philosophy, University of Skövde (SWE)

We experience affective feelings (i.e., emotions and moods) not only when we are awake but also when we are asleep — during dreaming. Despite considerable research, existing theories and empirical findings disagree about the frequency, nature, and correlates of dream affect. Although there is a large body of research on the neural basis of REM sleep, little is known about the specific neurophysiological markers for dream phenomenology, including dream affect. In this presentation, I will give an overview of recent research on (1) the frequency, valence, and phenomenological content of dream affect and how these are influenced by study methodology, (2) the neural correlates of dream affect, and (3) the continuity of affective feelings across the sleep-wake cycle. These studies show that the results and conclusions regarding dream affect are very different, even contradictory, depending on the methodology used to measure dream emotions. Findings also demonstrate cross-state continuity regarding both the phenomenology and the underlying neural processes of affective feelings. I will discuss the implications these findings have for the study of (the neural correlates of) affective experiences across the sleep-wake cycle.

Meditation, hypnagogia and the stability of consciousness

Tristan Bekinschtein

University of Cambridge

It seems limiting that we talk about phenomenology and experiences but then we measure reaction times and errors. Can we study the contents of our mind? I would argue that we are always studying content in cognitive neuroscience but not caring or not willing to engage in the question. I will present two main methods to capture what we think -direct and indirect- that may allow us to formalize the questions about content. I would also like to discuss two methods in cognitive neuroscience to map the underpinnings of the contents: neural decoding and intensity tracking. I will illustrate the results and discussion with EEG and fMRI experiments during pharmacologically-induced states, sleep transitions and meditative techniques.

Mind mapping with words: what computational speech approaches can tell us about our dreams

Natália Mota

Brain Institute UFRN and Physic's Department UFPE

Why do we dream? How does a dream reveal our inner reality? Those questions are for centuries in human culture and investigated in different ways, always facing a challenge: how to avoid the external subjectivity to interpret dreams out of the dreamer reality? Computational approaches that automatize semantic and emotional analysis are a possible path to solve this problem. During this talk, we will explore how to study memory reverberation at dreams using semantic analysis in a sleep-lab experiment and during remote access of dream reports during the COVID19 pandemic. We found that visual memory residue persists throughout the transition to sleep, increasing during N1 in proportion to the time spent in this stage. In contrast, the progression of sleep gradually neutralizes the affective memory residue, which decreases in proportion to the time spent in N1 and reaches a minimum during N2. During COVID 19 pandemics we also investigated how Does dreaming change and/or reflect mental suffering related to social isolation and the fear of contamination. For that purpose, we applied natural language processing tools to study 239 dream reports from 67 individuals either before the Covid-19 outbreak or during March-April, 2020, when quarantine was imposed in Brazil following the pandemic announcement by the WHO. Pandemic dreams showed a higher proportion of anger and sadness words and higher average semantic similarities to the terms “contamination” and “cleanness”.

The psychedelic state as a waking dream

Enzo Tagliazucchi

Physics Department, University of Buenos Aires

Ever since the modern rediscovery of psychedelic substances by Western society, several authors have independently proposed that their effects bear a high resemblance to the dreams and dreamlike experiences occurring naturally during the sleep-wake cycle. I will present evidence supporting this hypothesis, both from phenomenological and neurophysiological perspectives. First, I will discuss the results of large-scale semantic analyses comparing dream reports to those given by users of different psychoactive compounds, and demonstrate that the content of psychedelic experiences is the closest match to dream content. Second, I will present the results of EEG experiments conducted under the effects of N,N-dimethyltryptamine (DMT), a potent and short-lasting serotonergic psychedelic capable of inducing immersive and oneiric experiences, drawing parallels with the known electrophysiological changes that take place during the descent from wakefulness into REM sleep.