Dreaming, waking conscious experience, and the resting brain: report of subjective experience as a tool in the cognitive neurosciences

Even when we are ostensibly doing “nothing”—as during states of rest, sleep, and reverie—the brain continues to process information. In resting wakefulness, the mind generates thoughts, plans for the future, and imagines fictitious scenarios. In sleep, when the demands of sensory input are reduced, our experience turns to the thoughts and images we call “dreaming.” Far from being a meaningless distraction, the content of these subjective experiences provides an important and unique source of information about the activities of the resting mind and brain. In both wakefulness and sleep, spontaneous experience combines recent and remote memory fragments into novel scenarios. These conscious experiences may reflect the consolidation of recent memory into long-term storage, an adaptive process that functions to extract general knowledge about the world and adaptively respond to future events. Recent examples from psychology and neuroscience demonstrate that the use of subjective report can provide clues to the function(s) of rest and sleep

Sleep spindle deficits in antipsychotic-naïve early course schizophrenia and in non-psychotic first-degree relatives

Introduction: Chronic medicated patients with schizophrenia have marked reductions in sleep spindle activity and a correlated deficit in sleep-dependent memory consolidation. Using archival data, we investigated whether antipsychotic-naïve early course patients with schizophrenia and young non-psychotic first-degree relatives of patients with schizophrenia also show reduced sleep spindle activity and whether spindle activity correlates with cognitive function and symptoms. Method: Sleep spindles during Stage 2 sleep were compared in antipsychotic-naïve adults newly diagnosed with psychosis, young non-psychotic first-degree relatives of schizophrenia patients and two samples of healthy controls matched to the patients and relatives. The relations of spindle parameters with cognitive measures and symptom ratings were examined. Results: Early course schizophrenia patients showed significantly reduced spindle activity relative to healthy controls and to early course patients with other psychotic disorders. Relatives of schizophrenia patients also showed reduced spindle activity compared with controls. Reduced spindle activity correlated with measures of executive function in early course patients, positive symptoms in schizophrenia and IQ estimates across groups. Conclusions: Like chronic medicated schizophrenia patients, antipsychotic-naïve early course schizophrenia patients and young non-psychotic relatives of individuals with schizophrenia have reduced sleep spindle activity. These findings indicate that the spindle deficit is not an antipsychotic side-effect or a general feature of psychosis. Instead, the spindle deficit may predate the onset of schizophrenia, persist throughout its course and be an endophenotype that contributes to cognitive dysfunction

Memory for Semantically Related and Unrelated Declarative Information: The Benefit of Sleep, the Cost of Wake

Numerous studies have examined sleep's influence on a range of hippocampus-dependent declarative memory tasks, from text learning to spatial navigation. In this study, we examined the impact of sleep, wake, and time-of-day influences on the processing of declarative information with strong semantic links (semantically related word pairs) and information requiring the formation of novel associations (unrelated word pairs). Participants encoded a set of related or unrelated word pairs at either 9am or 9pm, and were then tested after an interval of 30 min, 12 hr, or 24 hr. The time of day at which subjects were trained had no effect on training performance or initial memory of either word pair type. At 12 hr retest, memory overall was superior following a night of sleep compared to a day of wakefulness. However, this performance difference was a result of a pronounced deterioration in memory for unrelated word pairs across wake; there was no sleep-wake difference for related word pairs. At 24 hr retest, with all subjects having received both a full night of sleep and a full day of wakefulness, we found that memory was superior when sleep occurred shortly after learning rather than following a full day of wakefulness. Lastly, we present evidence that the rate of deterioration across wakefulness was significantly diminished when a night of sleep preceded the wake period compared to when no sleep preceded wake, suggesting that sleep served to stabilize the memories against the deleterious effects of subsequent wakefulness. Overall, our results demonstrate that 1) the impact of 12 hr of waking interference on memory retention is strongly determined by word-pair type, 2) sleep is most beneficial to memory 24 hr later if it occurs shortly after learning, and 3) sleep does in fact stabilize declarative memories, diminishing the negative impact of subsequent wakefulness

Constructive Episodic Simulation in Dreams

Open data and analysis code for paper "Constructive Episodic Simulation in Dreams", published in PLoS One 2022. Archived here are: 1. Raw data in .Rdata format 2. R code used for analysis in .rmd format 3. R code used for analysis knit to HTML format Contact [email protected] with any question

Spontaneous entry into an offline state during wakefulness: A mechanism of memory consolidation

This OSF publication contains open resources from the following publication: Wamsley, E. J., & Summer, T. (2020). Spontaneous Entry into an “Offline” State during Wakefulness: A Mechanism of Memory Consolidation? Journal of Cognitive Neuroscience, 1–21. Documentation of our methods, our primary data files, and analysis code are included. Disclaimer: We are attempting to follow the "just post it!" philosophy, not allowing perfectionism to prevent us from openly sharing our materials. As a result, I apologize that these materials may not be optimally curated, organized, and documented. I am happy to answer what questions I can ([email protected]), however, extensive technical support won't be possible given our limited resources. We hope that these materials may be useful despite this

A Meta-Analysis of the Relation between Dream Content and Memory Consolidation

Data and R analysis code supporting the paper "A Meta-Analysis of the Relation between Dream Content and Memory Consolidation", accepted for publication in SLEEP in 2023; doi: https://doi.org/10.1093/sleep/zsad11

Unlearning implicit social biases during sleep: A failure to replicate

(Abstract) A 2015 article in Science (Hu et al.) proposed a new way to reduce implicit racial and gender biases during sleep. The method built on an existing counter-stereotype training procedure, using targeted memory reactivation to strengthen counter-stereotype memory by playing cues associated with the training during a 90min nap. If effective, this procedure would have potential real-world usefulness in reducing implicit biases and their myriad effects. We replicated this procedure on a sample of n=31 college students. Contrary to the results reported by Hu et al., we found no effect of cueing on implicit bias, either immediately following the nap or one week later. In fact, bias was non-significantly greater for cued than for uncued stimuli. Our failure to detect an effect of cueing on implicit bias could indicate either that the original report was a false positive, or that the current study is a false negative. However, several factors argue against Type II error in the current study. Critically, this replication was powered at 0.9 for detecting the originally reported cueing effect. Additionally, the 95% confidence interval for the cueing effect in the present study did not overlap with that of the originally reported effect; therefore, our observations are not easily explained as a noisy estimate of the same underlying effect. Ultimately, the outcome of this replication study reduces our confidence that cueing during sleep can reduce implicit bias. Here, we archive both the raw datafile (in SPSS format) used to generate these results, and the study manual documenting the setup and procedure. Citation for our associated publication: Humiston, Graelyn, and Erin J. Wamsley. “Unlearning Implicit Social Biases during Sleep: A Failure to Replicate.” PloS One 14, no. 1 (2019): e0211416

Effect of postlearning Meditation on Memory Consolidation: level of Focused Attention Matters

This OSF project contains methods, materials, and data for this publication: Collins, M. B., & Wamsley, E. J. (2020). Effect of postlearning meditation on memory consolidation: level of focused attention matters. Learning & memory (Cold Spring Harbor, N.Y.), 27(6), 250–253. https://doi.org/10.1101/lm.051151.11