Extending the Explanandum: A Commentary on Andy Clark

In this commentary, I suggest that the predictive processing framework (PP) might be applicable to areas beyond those identified by Clark. In particular, PP may be relevant for our understanding of perceptual content, consciousness, and for applied cognitive neuroscience. My main claim for each area is as follows:PP urges an organism-relative conception of perceptual content.Historical a priori accounts of the structure of perceptual experience converge with results from PP. There are a number of areas in which PP can find important practical applications, including education, public policy, and social interaction

Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement

Funder: Signe ja Ane Gyllenbergin Säätiö (Signe and Ane Gyllenberg Foundation); doi: https://doi.org/10.13039/501100004325Abstract: Recently, cortical correlates of specific dream contents have been reported, such as the activation of the sensorimotor cortex during dreamed hand clenching. Yet, despite a close resemblance of such activation patterns to those seen during the corresponding wakeful behaviour, the causal mechanisms underlying specific dream contents remain largely elusive. Here, we aimed to investigate the causal role of the sensorimotor cortex in generating movement and bodily sensations during REM sleep dreaming. Following bihemispheric transcranial direct current stimulation (tDCS) or sham stimulation, guided by functional mapping of the primary motor cortex, naive participants were awakened from REM sleep and responded to a questionnaire on bodily sensations in dreams. Electromyographic (EMG) and electroencephalographic (EEG) recordings were used to quantify physiological changes during the preceding REM period. We found that tDCS, compared to sham stimulation, significantly decreased reports of dream movement, especially of repetitive actions. Other types of bodily experiences, such as tactile or vestibular sensations, were not affected by tDCS, confirming the specificity of stimulation effects to movement sensations. In addition, tDCS reduced EEG interhemispheric coherence in parietal areas and affected the phasic EMG correlation between both arms. These findings show that a complex temporal reorganization of the motor network co-occurred with the reduction of dream movement, revealing a link between central and peripheral motor processes and movement sensations of the dream self. tDCS over the sensorimotor cortex interferes with dream movement during REM sleep, which is consistent with a causal contribution to dream experience and has broader implications for understanding the neural basis of self-experience in dreams

Focused wave interactions with floating structures: A blind comparative study

The paper presents results from the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) Blind Test Series 2. Without prior access to the physical data, participants, with numerical methods ranging from low-fidelity linear models to fully non-linear Navier−Stokes (NS) solvers, simulate the interaction between focused wave events and two separate, taut-moored, floating structures: a hemispherical-bottomed cylinder and a cylinder with a moonpool. The ‘blind’ numerical predictions for heave, surge, pitch and mooring load, are compared against physical measurements. Dynamic time warping is used to quantify the predictive capability of participating methods. In general, NS solvers and hybrid methods give more accurate predictions; however, heave amplitude is predicted reasonably well by all methods; and a WEC-Sim implementation, with CFD-informed viscous terms, demonstrates comparable predictive capability to even the stronger NS solvers. Large variations in the solutions are observed (even among similar methods), highlighting a need for standardisation in the numerical modelling of WSI problems

Just in time - dreamless sleep experience as pure subjective temporality: A commentary on Evan Thompson

In this commentary, I propose a strategy for extending Evan Thompson’s argument on the existence of dreamless sleep experience. My first aim is to show that the Indian debate on reports of having slept peacefully is importantly similar to debates in scientific dream research and contemporary Western philosophy on the trustworthiness of dream reports. This analogy leads to a surprising conclusion: the default view of conscious experience as that which disappears in dreamless sleep, though widely accepted in cognitive neuroscience, is in fact inconsistent with the methodological background assumptions of scientific dream research. Importantly, the methods already used in scientific dream research, as well as the theoretical justification on which they are based, can be extended to the investigation of dreamless sleep experience. Second, I sketch the outlines of a conceptual model of dreamless sleep experience as involving pure subjective temporality, or phenomenal experience characterized only by the phenomenal now and the sense of duration, but devoid of any further intentional content. I suggest that understood in this manner, dreamless sleep experience is a candidate for minimal phenomenal experience, or the simplest form in which a state can be phenomenally conscious. This model also extends existing work on minimal phenomenal selfhood in dreams. Third, I discuss three empirical examples that I take to be particularly promising candidates of dreamless sleep experience. These are certain forms of minimal or imageless lucid dreams, white dreams, and sleep-state misperception of the type most dramatically seen in subjective insomnia

How deep is the rift between conscious states in sleep and wakefulness? Spontaneous experience over the sleep-wake cycle:Spontaneous experience in sleep/waking

Whether we are awake or asleep is believed to mark a sharp divide between the types of conscious states we undergo in either behavioural state. Consciousness in sleep is often equated with dreaming and thought to be characteristically different from waking consciousness. Conversely, recent research shows that we spend a substantial amount of our waking lives mind wandering, or lost in spontaneous thoughts. Dreaming has been described as intensified mind wandering, suggesting that there is a continuum of spontaneous experience that reaches from waking into sleep. This challenges how we conceive of the behavioural states of sleep and wakefulness in relation to conscious states. I propose a conceptual framework that distinguishes different subtypes of spontaneous thoughts and experiences independently of their occurrence in sleep or waking. I apply this framework to selected findings from dream and mind-wandering research. I argue that to assess the relationship between spontaneous thoughts and experiences and the behavioural states of sleep and wakefulness, we need to look beyond dreams to consider kinds of sleep-related experience that qualify as dreamless. I conclude that if we consider the entire range of spontaneous thoughts and experiences, there appears to be variation in subtypes both within as well as across behavioural states. Whether we are sleeping or waking does not appear to strongly constrain which subtypes of spontaneous thoughts and experiences we undergo in those states. This challenges the conventional and coarse-grained distinction between sleep and waking and their putative relation to conscious states. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation’

Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams

The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, participants awakened from REM (rapid eye movement-) sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream state has not been investigated empirically or addressed from a theoretical perspective. Here, we report the results of an explorative web-based study in which participants were asked to rate their sensations during self-tickling and being tickled during wakefulness, imagination, and lucid dreaming. Our results, though highly preliminary, indicate that in the special case of lucid control dreams, the difference between self-tickling and being tickled by another is obliterated, with both self- and other produced tickles receiving similar ratings as self-tickling during wakefulness. This leads us to the speculative conclusion that in lucid control dreams, sensory attenuation for self-produced tickles spreads to those produced by non-self dream characters. These preliminary results provide the backdrop for a more general theoretical and metatheoretical discussion of tickling in lucid dreams in a predictive processing framework. We argue that the primary value of our study lies not so much in our results, which are subject to important limitations, but rather in the fact that they enable a new theoretical perspective on the relationship between sensory attenuation, the self-other distinction and agency, as well as suggest new questions for future research. In particular, the example of tickling during lucid dreaming raises the question of whether sensory attenuation and the self-other distinction can be simulated largely independently of external sensory input