Robert Stickgold

Robert Stickgold
Harvard Medical School | HMS · Department of Psychiatry

About

308
Publications
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Introduction

Publications

Publications (308)
Article
Full-text available
Motivated by the potential of objective neurophysiological markers to index thalamocortical function in patients with severe psychiatric illnesses, we comprehensively characterized key non-rapid eye movement (NREM) sleep parameters across multiple domains, their interdependencies, and their relationship to waking event-related potentials and sympto...
Article
Study Objectives Converging evidence from neuroimaging, sleep, and genetic studies suggests that dysregulation of thalamocortical interactions mediated by the thalamic reticular nucleus (TRN) contribute to autism spectrum disorder (ASD). Sleep spindles assay TRN function, and their coordination with cortical slow oscillations (SOs) indexes thalamoc...
Preprint
Full-text available
Motivated by the potential of objective neurophysiological markers to index thalamocortical function in patients with severe psychiatric illnesses, we comprehensively characterized key NREM sleep parameters across multiple domains, their interdependencies, and their relationship to waking event-related potentials and symptom severity. In 130 schizo...
Article
Sleep abnormalities are an early feature of schizophrenia (SZ) characterized by reductions in sleep spindles that have been associated with deficits in brain connectivity and cognitive function. This study investigated sleep spindle density (SSD) differences between SZ, first episode psychosis (FEP), and family high-risk (FHR) populations and match...
Book
Full-text available
Second Edition enriched with a Foreword written by Jakub Przybyła Frenis Zero publishing house, 2021, ISBN 978-88-97479-30-7 Presentation: The second edition of the book is foreworded by Jakub Przybyła who criticizes the idea of integrating neurobiology and psychotherapy based mainly on the study of psychoanalysis and neuropsychoanalysis. The autho...
Article
Extracting shared structure across our experiences allows us to generalize our knowledge to novel contexts. How do different brain states influence this ability to generalize? Using a novel category learning paradigm, we assess the effect of both sleep and time of day on generalization that depends on the flexible integration of recent information....
Preprint
Over time, memories lose episodic detail and become distorted, a process with serious ramifications for topics such as eyewitness identification. What are the processes which contribute to such transformation over time? We investigated the roles of post learning sleep and retrieval practice in memory accuracy, transformation, and distortion, using...
Article
Introduction The Apolipoprotein E (APOE)-ε4 genotype is a marker of susceptibility for late-onset Alzheimer’s disease (AD). Sleep disturbances may accelerate the aging process and increase the risk for future development of cognitive impairment and dementia. Given that the pathophysiological process of AD can predate its clinical manifestations by...
Article
Introduction A growing body of evidence suggests that sleep is critical for the processing and consolidation of emotional information into long-term memory. Previous research has indicated that emotional components of scenes particularly benefit from sleep in healthy groups, yet sleep dependent emotional memory processes remain unexplored in many c...
Article
Full-text available
Study objectives: Sleep spindles are defined based on expert observations of waveform features in the electroencephalogram traces. This is a potentially limiting characterization, as transient oscillatory bursts like spindles are easily obscured in the time-domain by higher amplitude activity at other frequencies or by noise. It is therefore highl...
Article
Sleep has been shown to be critical for memory consolidation, with some research suggesting that certain memories are prioritized for consolidation. Initial strength of a memory appears to be an important boundary condition in determining which memories are consolidated during sleep. However, the role of consolidation-mediating oscillations, such a...
Article
Evidence suggests that the brain preferentially consolidates memories during “offline” periods, in which an individual is not performing a task and their attention is otherwise undirected, including spans of quiet, resting wakefulness. Moreover, research has demonstrated that factors such as the initial encoding strength of information influence wh...
Article
Full-text available
Childhood epilepsy with centrotemporal spikes (CECTS) is the most common focal epilepsy syndrome, yet the cause of this disease remains unknown. Now recognized as a mild epileptic encephalopathy, children exhibit sleep-activated focal epileptiform discharges and cognitive difficulties during the active phase of the disease. The association between...
Chapter
Abnormal sleep is a prominent feature of many of the major neuropsychiatric disorders that likely reflects their pathophysiology and contributes to their associated symptoms and cognitive deficits.
Chapter
What is a dream? During wakefulness, the brain interprets information, stores memories, and uses knowledge to form and execute plans of action. In sleep, the brain continues these information-processing functions of the waking brain. Throughout the night, and even during the deepest phases of slow wave sleep, the sleeping brain replays past experie...
Article
Memory consolidation during sleep does not benefit all memories equally. Initial encoding strength appears to play a role in governing where sleep effects are seen, but it is unclear whether sleep preferentially consolidates weaker or stronger memories. We manipulated encoding strength along two dimensions-the number of item presentations, and succ...
Preprint
Full-text available
Extracting shared structure across our experiences allows us to generalize our knowledge to novel contexts. How do different brain states influence this ability to generalize? Using a novel category learning paradigm, we assess the effect of both sleep and time of day on generalization that depends on the flexible integration of recent information....
Article
Sleep spindles, defining oscillations of stage 2 non-rapid eye movement sleep (N2), mediate memory consolidation. Schizophrenia is characterized by reduced spindle activity that correlates with impaired sleep-dependent memory consolidation. In a small, randomized, placebo-controlled pilot study of schizophrenia, eszopiclone (Lunesta®), a nonbenzodi...
Article
Information processing during sleep is active, ongoing and accessible to engineering. Protocols such as targeted memory reactivation use sensory stimuli during sleep to reactivate memories and demonstrate subsequent, specific enhancement of their consolidation. These protocols rely on physiological, as opposed to phenomenological, evidence of their...
Article
Introduction Converging evidence supports the hypothesis that reduced sleep spindles and spindle-slow oscillation (SO) coordination contribute to cognitive deficits in schizophrenia. Closed-loop auditory stimulation in healthy adults increases sleep spindles and improves declarative memory consolidation. Here we investigated whether closed-loop aud...
Preprint
Full-text available
Evidence suggests that the brain preferentially consolidates memories during "offline" periods, in which an individual is not performing a task and their attention is otherwise undirected, including spans of quiet, resting wakefulness. Moreover, research has demonstrated that factors such as the initial encoding strength of information influence wh...
Preprint
Full-text available
Sleep has been shown to be critical for memory consolidation, with some research suggesting that certain memories are prioritized for consolidation. Initial strength of a memory appears to be an important boundary condition in determining which memories are consolidated during sleep. However, the role of consolidation-mediating oscillations, such a...
Article
Full-text available
Study objectives: The clinical importance of obstructive sleep apnea, which can be prevalent during REM sleep, is unclear. The present study examines the effect of REM-related obstructive sleep apnea on motor memory consolidation as well as on mood states. Methods: We compared performance on the motor sequence task (MST), psychomotor vigilance t...
Article
Sleep spindles, defining oscillations of non‐rapid eye movement stage 2 sleep (N2), mediate memory consolidation. Spindle density (spindles/minute) is a stable, heritable feature of the sleep electroencephalogram. In schizophrenia, reduced spindle density correlates with impaired sleep‐dependent memory consolidation and is a promising treatment tar...
Preprint
Sleep plays a critical role in the consolidation of memories. But this process is selective, with only some memories benefiting. One component of this selection process is encoding strength. The role that initial encoding strength plays in the prioritization for consolidation during sleep is currently unclear, with some studies suggesting that weak...
Article
Background: Microstates are periods of characteristic electroencephalographic signal topography that are related to activity in brain networks. Previous work has identified abnormal microstate parameters in individuals with psychotic disorders. We combined microstate analysis with sample entropy analysis to study the dynamics of resting-state netw...
Article
During sleep, the hippocampus plays an active role in consolidating memories that depend on it for initial encoding. There are hints in the literature that the hippocampus may have a broader influence, contributing to the consolidation of memories that may not initially require the area. We tested this possibility by evaluating learning and consoli...
Article
Full-text available
There is overwhelming evidence that sleep is crucial for memory consolidation. Patients with schizophrenia and their unaffected relatives have a specific deficit in sleep spindles, a defining oscillation of non-rapid eye movement (NREM) Stage 2 sleep that, in coordination with other NREM oscillations, mediate memory consolidation. In schizophrenia,...
Article
Background: Converging evidence implicates abnormal thalamocortical interactions in the pathophysiology of schizophrenia. This evidence includes consistent findings of increased resting-state functional connectivity of the thalamus with somatosensory and motor cortex during wake and reduced spindle activity during sleep. We hypothesized that these...
Article
Introduction Patients with schizophrenia have sleep spindle deficits that correlate with impaired sleep-dependent memory consolidation. In a previous study of schizophrenia, eszopiclone, a non-benzodiazepine sedative hypnotic, despite increasing spindles, failed to improve memory. Here, we investigated whether this failure reflected that eszopiclon...
Article
Introduction A large body of evidence has shown that sleep plays a critical role in the consolidation of memories, a process facilitated in part by sleep spindles, a hallmark feature of non-rapid eye movement (NREM) sleep. It is less clear how the brain selects and prioritizes which memories get consolidated during sleep. Here, we used EEG to ident...
Article
Introduction Recent data implicate abnormalities of the thalamic reticular nucleus (TRN) and thalamocortical circuitry in schizophrenia (SZ) risk. Sleep spindles are initiated by the TRN and propagated to the cortex via thalamocortical feedback loops.During wakefulness, TRN modulates sensory processing by gating thalamocortical communication. Patie...
Article
Full-text available
Introduction Prospective memory (PM)—the ability to plan and spontaneously remember to execute activities in the future—has been shown to improve across periods of sleep. While evidence indicates PM benefits most from SWS-rich sleep, the specific components of sleep that benefit PM performance remain undetermined. Methods Participants arrived at 9...
Article
Introduction There is converging evidence that motor-skill learning is consolidated by sleep spindles during non-rapid eye movement stage 2 (N2) sleep, resulting in improved post-sleep performance. We localized learning-related changes in spindle activity with source localization of simultaneous electroencephalogram (EEG) and magnetoencephalography...
Article
Introduction Sleep has been shown to facilitate the consolidation of explicit motor-sequence learning on the finger-tapping motor sequence task (MST). However, whether sleep's contribution constitutes stabilization or enhancement is currently under debate. A transient boost in performance after a short break from practice on the MST has been report...
Article
Introduction Sleep spindles mediate memory consolidation during sleep and are markedly reduced in schizophrenia. While spindle deficits correlate with impaired sleep-dependent memory, pharmacologically increasing spindle density in schizophrenia does not always improve memory. This may be because coupling with other NREM sleep oscillations like hip...
Article
Full-text available
Sleep and emotion are both powerful modulators of the long-term stability of episodic memories, but precisely how these factors interact remains unresolved. We assessed changes in item recognition, contextual memory, and affective tone for negative and neutral memories across a 12 h interval containing sleep or wakefulness in 71 human volunteers. O...
Preprint
Full-text available
During sleep, the hippocampus plays an active role in consolidating memories that depend on it for initial encoding. There are hints in the literature that the hippocampus may have a broader influence, contributing to the consolidation of memories that may not initially require the area. We tested this possibility by evaluating learning and consoli...
Article
Full-text available
Slow oscillations and sleep spindles, the canonical electrophysiological oscillations of non-rapid eye movement sleep, are thought to gate incoming sensory information, underlie processes of sleep-dependent memory consolidation, and are altered in various neuropsychiatric disorders. Accumulating evidence of the predominantly local expression of the...
Article
Full-text available
Sleep following learning benefits memory. One model attributes this effect to the iterative “reactivation” of memory traces in the sleeping brain, demonstrated in animal models. Although technical limitations prohibit using the same methods to observe memory reactivation in the human brain, the study of mental activity during sleep provides an alte...
Preprint
Full-text available
Sleep and emotion are both powerful modulators of the long-term stability of episodic memories, but precisely how these factors interact remains unresolved. We assessed changes in item recognition, contextual memory, and affective tone for negative and neutral memories across a 12 h interval containing sleep or wakefulness in 71 human volunteers. O...
Article
Introduction A large body of evidence has shown that sleep plays an important role in the consolidation of declarative memory. More recently, it has been suggested that the brain prioritizes certain memories to be consolidated over others. The mechanisms underlying this remain unclear. This study investigated the role initial encoding strength may...
Article
Introduction Sleep is traditionally characterized through patterns observed in the time-domain electroencephalogram (EEG). These include persistent oscillations, such as slow wave activity, or transient oscillatory activity, such as spindles and K-complexes. Time-domain identification of oscillations is difficult, with waveforms frequently being ob...
Article
Introduction Accumulating evidence suggests that sleep-dependent memory consolidation is impaired in schizophrenia. The majority of this research however has focused on chronically medicated patients, making it hard to rule out medication effects. Here, we investigate sleep-dependent memory consolidation in early-course, minimally medicated patient...
Article
Introduction Prior work has demonstrated that features of objects that are shared with other members of a category are better remembered after a night of sleep. We set out to test whether sleep would also benefit generalization to novel object category exemplars. Methods Participants learned visual and verbal features of three categories (A, B, an...
Article
Introduction Memory consolidation is stabilized and even enhanced by sleep (and particularly by 12–15 Hz sleep spindles in NREM stage 2 sleep) in healthy children but it is unclear what happens to these processes when sleep is disturbed by obstructive sleep disordered breathing. This cross-sectional study investigates differences in declarative mem...
Article
Introduction Schizophrenia (SZ) is marked by impairments in cognition, learning, and memory. Sleep spindles, a defining characteristic of Stage 2 NREM sleep, are thought to mediate memory consolidation during sleep and are markedly reduced in SZ. While spindle deficits correlate with impaired sleep-dependent memory in SZ, pharmacologically increasi...
Article
Objective: Cognitive deficits in schizophrenia are the strongest predictor of disability and effective treatment is lacking. This reflects our limited mechanistic understanding and consequent lack of treatment targets. In schizophrenia, impaired sleep-dependent memory consolidation correlates with reduced sleep spindle activity, suggesting sleep s...
Article
Full-text available
Offline reactivation of task-related neural activity has been demonstrated in animals but is difficult to directly observe in humans. We sought to identify potential electroencephalographic (EEG) markers of offline memory processing in human subjects by identifying a set of characteristic EEG topographies (“microstates”) that occurred as subjects l...
Preprint
Full-text available
The temporal coordination of slow oscillations and sleep spindles is believed to underlie processes of sleep-dependent memory consolidation and reorganization. Accumulating evidence of the predominantly local expression of these individual oscillatory rhythms suggests that their interaction may have a similar local component. However, it is unclear...
Article
Full-text available
Individual differences in brain organization exist at many spatial and temporal scales, contributing to the substantial heterogeneity underlying human thought and behavior. Oscillatory neural activity is crucial for these behaviors, but how such rhythms are expressed across the cortex within and across individuals has not been thoroughly characteri...
Article
Your nightly rest turns out to affect your mind and health more than anyone suspected
Article
Full-text available
Memory consolidation is stabilized and even enhanced by sleep (and particularly by 12-15 Hz sleep spindles in NREM stage 2 sleep) in healthy children but it is unclear what happens to these processes when sleep is disturbed by obstructive sleep disordered breathing. This cross-sectional study investigates differences in declarative memory consolida...
Article
Full-text available
Sleep spindles are transient oscillatory waveforms that occur during non-rapid eye movement (NREM) sleep across widespread cortical areas. In humans, spindles can be classified as either slow or fast, but large individual differences in spindle frequency as well as methodological difficulties have hindered progress towards understanding their funct...