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Lacaux C, Strauss M, Bekinschtein TA, Oudiette D. Embracing sleep-onset complexity. Trends Neurosci 2024; 47:273-288. [PMID: 38519370 DOI: 10.1016/j.tins.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/17/2024] [Accepted: 02/07/2024] [Indexed: 03/24/2024]
Abstract
Sleep is crucial for many vital functions and has been extensively studied. By contrast, the sleep-onset period (SOP), often portrayed as a mere prelude to sleep, has been largely overlooked and remains poorly characterized. Recent findings, however, have reignited interest in this transitional period and have shed light on its neural mechanisms, cognitive dynamics, and clinical implications. This review synthesizes the existing knowledge about the SOP in humans. We first examine the current definition of the SOP and its limits, and consider the dynamic and complex electrophysiological changes that accompany the descent to sleep. We then describe the interplay between internal and external processing during the wake-to-sleep transition. Finally, we discuss the putative cognitive benefits of the SOP and identify novel directions to better diagnose sleep-onset disorders.
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Affiliation(s)
- Célia Lacaux
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Institut du Cerveau (Paris Brain Institute), Institut du Cerveau et de la Moelle Épinière (ICM), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Paris 75013, France.
| | - Mélanie Strauss
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition and Neurosciences (CRCN), Université Libre de Bruxelles, B-1050 Brussels, Belgium; Departments of Neurology, Psychiatry, and Sleep Medicine, Hôpital Universitaire de Bruxelles, Site Erasme, Université Libre de Bruxelles, B-1070 Brussels, Belgium
| | - Tristan A Bekinschtein
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Delphine Oudiette
- Institut du Cerveau (Paris Brain Institute), Institut du Cerveau et de la Moelle Épinière (ICM), Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Paris 75013, France; Assistance Publique - Hopitaux de Paris (AP-HP), Hôpital Pitié-Salpêtrière, Service des Pathologies du Sommeil, National Reference Centre for Narcolepsy, Paris 75013, France.
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Andrillon T, Taillard J, Strauss M. Sleepiness and the transition from wakefulness to sleep. Neurophysiol Clin 2024; 54:102954. [PMID: 38460284 DOI: 10.1016/j.neucli.2024.102954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 03/11/2024] Open
Abstract
The transition from wakefulness to sleep is a progressive process that is reflected in the gradual loss of responsiveness, an alteration of cognitive functions, and a drastic shift in brain dynamics. These changes do not occur all at once. The sleep onset period (SOP) refers here to this period of transition between wakefulness and sleep. For example, although transitions of brain activity at sleep onset can occur within seconds in a given brain region, these changes occur at different time points across the brain, resulting in a SOP that can last several minutes. Likewise, the transition to sleep impacts cognitive and behavioral levels in a graded and staged fashion. It is often accompanied and preceded by a sensation of drowsiness and the subjective feeling of a need for sleep, also associated with specific physiological and behavioral signatures. To better characterize fluctuations in vigilance and the SOP, a multidimensional approach is thus warranted. Such a multidimensional approach could mitigate important limitations in the current classification of sleep, leading ultimately to better diagnoses and treatments of individuals with sleep and/or vigilance disorders. These insights could also be translated in real-life settings to either facilitate sleep onset in individuals with sleep difficulties or, on the contrary, prevent or control inappropriate sleep onsets.
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Affiliation(s)
- Thomas Andrillon
- Paris Brain Institute, Sorbonne Université, Inserm-CNRS, Paris 75013, France; Monash Centre for Consciousness & Contemplative Studies, Monash University, Melbourne, VIC 3800, Australia
| | - Jacques Taillard
- Univ. Bordeaux, CNRS, SANPSY, UMR 6033, F-33000 Bordeaux, France
| | - Mélanie Strauss
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (H.U.B), CUB Hôpital Érasme, Services de Neurologie, Psychiatrie et Laboratoire du sommeil, Route de Lennik 808 1070 Bruxelles, Belgium; Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition and Neurosciences (CRCN), Université Libre de Bruxelles, B-1050 Brussels, Belgium.
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3
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Smaczny S, Bauder D, Sperber C, Karnath HO, de Haan B. Reducing alertness does not affect line bisection bias in neurotypical participants. Exp Brain Res 2024; 242:195-204. [PMID: 37994915 PMCID: PMC10786967 DOI: 10.1007/s00221-023-06738-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/31/2023] [Indexed: 11/24/2023]
Abstract
Alertness, or one's general readiness to respond to stimulation, has previously been shown to affect spatial attention. However, most of this previous research focused on speeded, laboratory-based reaction tasks, as opposed to the classical line bisection task typically used to diagnose deficits of spatial attention in clinical settings. McIntosh et al. (Cogn Brain Res 25:833-850, 2005) provide a form of line bisection task which they argue can more sensitively assess spatial attention. Ninety-eight participants were presented with this line bisection task, once with and once without spatial cues, and both before and after a 50-min vigilance task that aimed to decrease alertness. A single participant was excluded due to potentially inconsistent behaviour in the task, leaving 97 participants for the full analyses. While participants were, on a group level, less alert after the 50-min vigilance task, they showed none of the hypothesised effects of reduced alertness on spatial attention in the line bisection task, regardless of with or without spatial cues. Yet, they did show the proposed effect of decreased alertness leading to a lower level of general attention. This suggests that alertness has no effect on spatial attention, as measured by a line bisection task, in neurotypical participants. We thus conclude that, in neurotypical participants, the effect of alertness on spatial attention can be examined more sensitively with tasks requiring a speeded response compared to unspeeded tasks.
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Affiliation(s)
- Stefan Smaczny
- Center of Neurology, Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Dominik Bauder
- Center of Neurology, Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Christoph Sperber
- Department of Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Hans-Otto Karnath
- Center of Neurology, Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Psychology, University of South Carolina, Columbia, USA
| | - Bianca de Haan
- Division of Psychology, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge, UB8 3PH, UK.
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Andrillon T, Oudiette D. What is sleep exactly? Global and local modulations of sleep oscillations all around the clock. Neurosci Biobehav Rev 2023; 155:105465. [PMID: 37972882 DOI: 10.1016/j.neubiorev.2023.105465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 09/29/2023] [Accepted: 11/10/2023] [Indexed: 11/19/2023]
Abstract
Wakefulness, non-rapid eye-movement (NREM) and rapid eye-movement (REM) sleep differ from each other along three dimensions: behavioral, phenomenological, physiological. Although these dimensions often fluctuate in step, they can also dissociate. The current paradigm that views sleep as made of global NREM and REM states fail to account for these dissociations. This conundrum can be dissolved by stressing the existence and significance of the local regulation of sleep. We will review the evidence in animals and humans, healthy and pathological brains, showing different forms of local sleep and the consequences on behavior, cognition, and subjective experience. Altogether, we argue that the notion of local sleep provides a unified account for a host of phenomena: dreaming in REM and NREM sleep, NREM and REM parasomnias, intrasleep responsiveness, inattention and mind wandering in wakefulness. Yet, the physiological origins of local sleep or its putative functions remain unclear. Exploring further local sleep could provide a unique and novel perspective on how and why we sleep.
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Affiliation(s)
- Thomas Andrillon
- Paris Brain Institute, Sorbonne Université, Inserm-CNRS, Paris 75013, France; Monash Centre for Consciousness & Contemplative Studies, Monash University, Melbourne, VIC 3800, Australia.
| | - Delphine Oudiette
- Paris Brain Institute, Sorbonne Université, Inserm-CNRS, Paris 75013, France
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Andrillon T. How we sleep: From brain states to processes. Rev Neurol (Paris) 2023; 179:649-657. [PMID: 37625978 DOI: 10.1016/j.neurol.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023]
Abstract
All our lives, we alternate between wakefulness and sleep with direct consequences on our ability to interact with our environment, the dynamics and contents of our subjective experience, and our brain activity. Consequently, sleep has been extensively characterised in terms of behavioural, phenomenological, and physiological changes, the latter constituting the gold standard of sleep research. The common view is thus that sleep represents a collection of discrete states with distinct neurophysiological signatures. However, recent findings challenge such a monolithic view of sleep. Indeed, there can be sharp discrepancies in time and space in the activity displayed by different brain regions or networks, making it difficult to assign a global vigilance state to such a mosaic of contrasted dynamics. Viewing sleep as a multidimensional continuum rather than a succession of non-overlapping and mutually exclusive states could account for these local aspects of sleep. Moving away from the focus on sleep states, sleep can also be investigated through the brain processes that are present in sleep, if not necessarily specific to sleep. This focus on processes rather than states allows to see sleep for what it does rather than what it is, avoiding some of the limitations of the state perspective and providing a powerful heuristic to understand sleep. Indeed, what is sleep if not a process itself that makes up wake up every morning with a brain cleaner, leaner and less cluttered.
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Affiliation(s)
- T Andrillon
- Paris Brain Institute, Sorbonne Université, Inserm, CNRS, 75013 Paris, France; Monash Centre for Consciousness & Contemplative Studies, Monash University, Melbourne, VIC 3800, Australia.
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Biabani N, Birdseye A, Higgins S, Delogu A, Rosenzweig J, Cvetkovic Z, Nesbitt A, Drakatos P, Steier J, Kumari V, O’Regan D, Rosenzweig I. The neurophysiologic landscape of the sleep onset: a systematic review. J Thorac Dis 2023; 15:4530-4543. [PMID: 37691675 PMCID: PMC10482638 DOI: 10.21037/jtd-23-325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/21/2023] [Indexed: 09/12/2023]
Abstract
Background The sleep onset process is an ill-defined complex process of transition from wakefulness to sleep, characterized by progressive modifications at the subjective, behavioural, cognitive, and physiological levels. To this date, there is no international consensus which could aid a principled characterisation of this process for clinical research purposes. The current review aims to systemise the current knowledge about the underlying mechanisms of the natural heterogeneity of this process. Methods In this systematic review, studies investigating the process of the sleep onset from 1970 to 2022 were identified using electronic database searches of PsychINFO, MEDLINE, and Embase. Results A total of 139 studies were included; 110 studies in healthy participants and 29 studies in participants with sleep disorders. Overall, there is a limited consensus across a body of research about what distinct biomarkers of the sleep onset constitute. Only sparse data exists on the physiology, neurophysiology and behavioural mechanisms of the sleep onset, with majority of studies concentrating on the non-rapid eye movement stage 2 (NREM 2) as a potentially better defined and a more reliable time point that separates sleep from the wake, on the sleep wake continuum. Conclusions The neurophysiologic landscape of sleep onset bears a complex pattern associated with a multitude of behavioural and physiological markers and remains poorly understood. The methodological variation and a heterogenous definition of the wake-sleep transition in various studies to date is understandable, given that sleep onset is a process that has fluctuating and ill-defined boundaries. Nonetheless, the principled characterisation of the sleep onset process is needed which will allow for a greater conceptualisation of the mechanisms underlying this process, further influencing the efficacy of current treatments for sleep disorders.
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Affiliation(s)
- Nazanin Biabani
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
| | - Adam Birdseye
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Sean Higgins
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Alessio Delogu
- James Black Centre, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
| | - Jan Rosenzweig
- Department of Engineering, King’s College London, London, UK
| | - Zoran Cvetkovic
- Department of Engineering, King’s College London, London, UK
| | - Alexander Nesbitt
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
- Department of Neurology, Guy’s Hospital, Guy’s and St. Thomas’ NHS Foundation Trust, London, UK
| | - Panagis Drakatos
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
- School of Basic and Medical Biosciences, Faculty of Life Science and Medicine, King’s College London, London, UK
| | - Joerg Steier
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
- School of Basic and Medical Biosciences, Faculty of Life Science and Medicine, King’s College London, London, UK
| | - Veena Kumari
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Centre for Cognitive Neuroscience (CCN), College of Health, Medicine and Life Sciences, Brunel University London, London, UK
| | - David O’Regan
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
- School of Basic and Medical Biosciences, Faculty of Life Science and Medicine, King’s College London, London, UK
| | - Ivana Rosenzweig
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, London, UK
- Sleep Disorders Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
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Danesin L, Oliveri M, Semenza C, Bottini G, Burgio F, Giustiniani A. Prism adaptation in patients with unilateral lesion of the parietal or cerebellar cortex: A pilot study on two single cases using a concurrent exposure procedure. Neuropsychologia 2023; 184:108557. [PMID: 37011723 DOI: 10.1016/j.neuropsychologia.2023.108557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023]
Abstract
Neuroimaging studies showed that prism adaptation (PA), a widely used tool for the rehabilitation of neglect, involves a wide network of brain regions including the parietal cortex and the cerebellum. In particular, the parietal cortex has been suggested to mediate the initial stage of PA through conscious compensatory mechanisms as a reaction to the deviation induced by PA. The cerebellum, on the other side, intervenes in sensory errors prediction to update internal models in later stages. It has been suggested that two mechanisms may underlie PA effects: recalibration, a strategic cognitive process occurring in the initial stages of PA, and realignment, a fully automatic reorganization of spatial maps emerging later and more slowly in time. The parietal lobe has been proposed to be involved mainly in the recalibration whereas the realignment would be carried over by the cerebellum. Previous studies have investigated the effects of a lesion involving either the cerebellum or the parietal lobe in PA taking into account both realignment and recalibration processes. Conversely, no studies have compared the performance of a patient with a cerebellar lesion to that of a patient with a parietal lesion. In the present study, we used a recently developed technique for digital PA to test differences in visuomotor learning after a single session of PA in a patient with parietal and a patient with cerebellar lesions, respectively. The PA procedure, in this case, includes a digital pointing task based on a concurrent exposure technique, which allows patients to fully see their arm during the pointing task. This procedure has been shown to be as effective as the terminal exposure condition in neglect rehabilitation albeit different processes take place during concurrent exposure condition compared to the most used terminal exposure (allowing to see only the final part of the movement). Patients' performances were compared to that of a control group. A single session of PA was administered to 1) a patient (BC) with left parieto-occipital lesion involving SPL and IPL, 2) a patient (TGM) with a stroke in the territory sub-served by the SCA in the cerebellum, and 3) 14 healthy controls (HC). The task included three conditions: before wearing prismatic goggles (pre-exposure), while wearing prisms (exposure) and after removing the goggles (post-exposure). Mean deviations were calculated for the following phases: pre-exposure, early-exposure, late-exposure, post-exposure. The presence of after-effect was calculated as the difference between pre-exposure and post-exposure conditions. For each of these conditions, patients' performance was compared to that of the control group by using a modified Crawford t-test. We found that the patient with the parietal lesion had a significantly different performance in the late-exposure and in the post-exposure compared to both HC and the patient with the cerebellar lesion. Conversely, no differences were observed between TGM and HC across all the conditions. Our results show an increase in the magnitude of the adaptation during the late stage of PA in the patient with the parietal lesion whereas no differences in the performance between the cerebellar patient and the controls were found. These results confirm previous studies suggesting that the parietal cortex is an important node of a wider network involved in PA effect. Furthermore, results in the cerebellar patient suggest that visuomotor learning is not affected by lesions of the SCA territory when a concurrent exposure is used as, in such case, it less relies on sensory errors prediction to update internal models. Results are discussed considering the novelty of the applied PA technique.
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Affiliation(s)
- L Danesin
- IRCCS San Camillo Hospital, Via Alberoni 70, 30126, Venice, Italy.
| | - M Oliveri
- Department SPPEF, University of Palermo, Italy.
| | - C Semenza
- ERN Neuromuscular Center, Department of Neurosciences, University of Padova, 35129, Padova, Italy.
| | - G Bottini
- Department of Brain and Behavioral Science, University of Pavia, 27100, Pavia, Italy; ASST GOM Niguarda, Milan, Italy; NeuroMI, Milan, Italy.
| | - F Burgio
- IRCCS San Camillo Hospital, Via Alberoni 70, 30126, Venice, Italy.
| | - A Giustiniani
- IRCCS San Camillo Hospital, Via Alberoni 70, 30126, Venice, Italy.
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Peers PV, Punton SF, Murphy FC, Watson P, Bateman A, Duncan J, Astle DE, Hampshire A, Manly T. A randomized control trial of the effects of home-based online attention training and working memory training on cognition and everyday function in a community stroke sample. Neuropsychol Rehabil 2022; 32:2603-2627. [PMID: 34505555 PMCID: PMC7615301 DOI: 10.1080/09602011.2021.1972817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/20/2021] [Indexed: 12/30/2022]
Abstract
Cognitive difficulties are common following stroke and can have widespread impacts on everyday functioning. Technological advances offer the possibility of individualized cognitive training for patients at home, potentially providing a low-cost, low-intensity adjunct to rehabilitation services. Using this approach, we have previously demonstrated post-training improvements in attention and everyday functioning in fronto-parietal stroke patients. Here we examine whether these benefits are observed more broadly in a community stroke sample. Eighty patients were randomized to either 4 weeks of online adaptive attention training (SAT), working memory training (WMT) or waitlist (WL). Cognitive and everyday function measures were collected before and after the intervention, and after 3 months. During training, weekly measures of patients' subjective functioning were collected. The training was well received and compliance good. No differences in our primary end-point, spatial bias, or other cognitive functions were observed. However, on patient-reported outcomes, SAT participants showed greater levels of improvement in everyday functioning than WMT or WL participants. In line with our previous work, everyday functioning improvements were greatest for patients with spatial impairments and those who received SAT training. Whether attention training can be recommended for stroke survivors depends on whether cognitive test performance or everyday functioning is considered more relevant.
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Affiliation(s)
- Polly V. Peers
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Sarah F. Punton
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Fionnuala C. Murphy
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Peter Watson
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Andrew Bateman
- Oliver Zangwill Centre, Cambridge Community Services NHS Trust, Ely, UK
- School of Health and Social Care, University of Essex, Colchester, UK
| | - John Duncan
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Duncan E. Astle
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Adam Hampshire
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Tom Manly
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Lacaux C, Andrillon T, Arnulf I, Oudiette D. Memory loss at sleep onset. Cereb Cortex Commun 2022; 3:tgac042. [PMID: 36415306 PMCID: PMC9677600 DOI: 10.1093/texcom/tgac042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 11/22/2022] Open
Abstract
Every night, we pass through a transitory zone at the borderland between wakefulness and sleep, named the first stage of nonrapid eye movement sleep (N1). N1 sleep is associated with increased hippocampal activity and dream-like experiences that incorporate recent wake materials, suggesting that it may be associated with memory processing. Here, we investigated the specific contribution of N1 sleep in the processing of memory traces. Participants were asked to learn the precise locations of 48 objects on a grid and were then tested on their memory for these items before and after a 30-min rest during which participants either stayed fully awake or transitioned toward N1 or deeper (N2) sleep. We showed that memory recall was lower (10% forgetting) after a resting period, including only N1 sleep compared to N2 sleep. Furthermore, the ratio of alpha/theta power (an electroencephalography marker of the transition toward sleep) correlated negatively with the forgetting rate when taking into account all sleepers (N1 and N2 groups combined), suggesting a physiological index for memory loss that transcends sleep stages. Our findings suggest that interrupting sleep onset at N1 may alter sleep-dependent memory consolidation and promote forgetting.
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Affiliation(s)
- Célia Lacaux
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Mov'it team, Inserm, CNRS, 47-83 boulevard de l'Hôpital , Paris 75013 , France
| | - Thomas Andrillon
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Mov'it team, Inserm, CNRS, 47-83 boulevard de l'Hôpital , Paris 75013 , France
| | - Isabelle Arnulf
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Mov'it team, Inserm, CNRS, 47-83 boulevard de l'Hôpital , Paris 75013 , France
- AP-HP, Hôpital Pitié-Salpêtrière, Service des Pathologies du Sommeil, National Reference Centre for Narcolepsy , 47-83 boulevard de l'Hôpital, Paris 75013 , France
| | - Delphine Oudiette
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Mov'it team, Inserm, CNRS, 47-83 boulevard de l'Hôpital , Paris 75013 , France
- AP-HP, Hôpital Pitié-Salpêtrière, Service des Pathologies du Sommeil, National Reference Centre for Narcolepsy , 47-83 boulevard de l'Hôpital, Paris 75013 , France
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10
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Alcaide S, Sitt J, Horikawa T, Romano A, Maldonado AC, Ibanez A, Sigman M, Kamitani Y, Barttfeld P. fMRI lag structure during waking up from early sleep stages. Cortex 2021; 142:94-103. [PMID: 34256198 PMCID: PMC11170464 DOI: 10.1016/j.cortex.2021.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 12/30/2020] [Accepted: 06/04/2021] [Indexed: 11/29/2022]
Abstract
The brain mechanisms by which we transition from sleep to a conscious state remain largely unknown in humans, partly because of methodological challenges. Here we study a pre-existing dataset of waking up participants originally designed for a study of dreaming (Horikawa, Tamaki, Miyawaki, & Kamitani, 2013) and suggest that suddenly awakening from early sleep stages results from a two-stage process that involves a sequence of cortical and subcortical brain activity. First, subcortical and sensorimotor structures seem to be recruited before most cortical regions, followed by fast, ignition-like whole-brain activation-with frontal regions engaging a little after the rest of the brain. Second, a comparably slower and possibly mirror-reversed stage might take place, with cortical regions activating before subcortical structures and the cerebellum. This pattern of activation points to a key role of subcortical structures for the initiation and maintenance of conscious states.
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Affiliation(s)
- Santiago Alcaide
- Cognitive Science Group, Instituto de Investigaciones Psicológicas, Facultad de Psicología Universidad Nacional de Córdoba - CONICET, Argentina
| | - Jacobo Sitt
- INSERM, U 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle Epinière, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | - Tomoyasu Horikawa
- Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International (ATR), Kyoto, Japan
| | - Alvaro Romano
- Cognitive Science Group, Instituto de Investigaciones Psicológicas, Facultad de Psicología Universidad Nacional de Córdoba - CONICET, Argentina
| | - Ana Carolina Maldonado
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad de Córdoba, CIEM-CONICET, Spain
| | - Agustín Ibanez
- Latin American Brain Health (BrainLat), Universidad Adolfo Ibáñez, Santiago, Chile; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina; Cognitive Neuroscience Center (CNC), Universidad de San Andrés, Argentina; Global Brain Health Institute (GBHI), University of California San Francisco (UCSF), USA
| | - Mariano Sigman
- Laboratorio de Neurociencia, Universidad Torcuato Di Tella, Buenos Aires, Argentina; Facultad de Lenguas y Educación, Universidad Nebrija, Madrid, Spain
| | - Yukiyasu Kamitani
- Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International (ATR), Kyoto, Japan; Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Pablo Barttfeld
- Cognitive Science Group, Instituto de Investigaciones Psicológicas, Facultad de Psicología Universidad Nacional de Córdoba - CONICET, Argentina.
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Chandrakumar D, Coussens S, Keage HAD, Banks S, Dorrian J, Loetscher T. Monotonous driving induces shifts in spatial attention as a function of handedness. Sci Rep 2021; 11:10155. [PMID: 33980882 PMCID: PMC8114912 DOI: 10.1038/s41598-021-89054-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/13/2021] [Indexed: 11/08/2022] Open
Abstract
Current evidence suggests that the ability to detect and react to information under lowered alertness conditions might be more impaired on the left than the right side of space. This evidence derives mainly from right-handers being assessed in computer and paper-and-pencil spatial attention tasks. However, there are suggestions that left-handers might show impairments on the opposite (right) side compared to right-handers with lowered alertness, and it is unclear whether the impairments observed in the computer tasks have any real-world implications for activities such as driving. The current study investigated the alertness and spatial attention relationship under simulated monotonous driving in left- and right-handers. Twenty left-handed and 22 right-handed participants (15 males, mean age = 23.6 years, SD = 5.0 years) were assessed on a simulated driving task (lasting approximately 60 min) to induce a time-on-task effect. The driving task involved responding to stimuli appearing at six different horizontal locations on the screen, whilst driving in a 50 km/h zone. Decreases in alertness and driving performance were evident with time-on-task in both handedness groups. We found handedness impacts reacting to lateral stimuli differently with time-on-task: right-handers reacted slower to the leftmost stimuli, while left-handers showed the opposite pattern (although not statistically significant) in the second compared to first half of the drive. Our findings support suggestions that handedness modulates the spatial attention and alertness interactions. The interactions were observed in a simulated driving task which calls for further research to understand the safety implications of these interactions for activities such as driving.
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Affiliation(s)
- D Chandrakumar
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.
| | - S Coussens
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - H A D Keage
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - S Banks
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - J Dorrian
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - T Loetscher
- Cognitive Ageing and Impairment Neurosciences Laboratory, Behaviour-Brain-Body Research Centre, School of Psychology, Justice & Society, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
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12
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Bareham CA, Oxner M, Gastrell T, Carmel D. Beyond the neural correlates of consciousness: using brain stimulation to elucidate causal mechanisms underlying conscious states and contents. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1840405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Corinne A. Bareham
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - Matt Oxner
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - Tim Gastrell
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - David Carmel
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
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13
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Chandrakumar D, Dorrian J, Banks S, Keage HAD, Coussens S, Gupta C, Centofanti SA, Stepien JM, Loetscher T. The relationship between alertness and spatial attention under simulated shiftwork. Sci Rep 2020; 10:14946. [PMID: 32917940 PMCID: PMC7486912 DOI: 10.1038/s41598-020-71800-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/22/2020] [Indexed: 01/28/2023] Open
Abstract
Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness; suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.
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Affiliation(s)
- D Chandrakumar
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia.
| | - J Dorrian
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
| | - S Banks
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
| | - H A D Keage
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
| | - S Coussens
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
| | - C Gupta
- Appleton Institute, Central Queensland University, Health, Medical and Applied Sciences, Adelaide, SA, Australia
| | - S A Centofanti
- University of South Australia Online, Adelaide, SA, Australia
| | - J M Stepien
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
| | - T Loetscher
- Behaviour-Brain-Body Research Centre, Justice & Society, University of South Australia, Adelaide, SA, Australia
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14
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Canales-Johnson A, Beerendonk L, Blain S, Kitaoka S, Ezquerro-Nassar A, Nuiten S, Fahrenfort J, van Gaal S, Bekinschtein TA. Decreased Alertness Reconfigures Cognitive Control Networks. J Neurosci 2020; 40:7142-7154. [PMID: 32801150 PMCID: PMC7480250 DOI: 10.1523/jneurosci.0343-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/02/2020] [Accepted: 07/10/2020] [Indexed: 11/21/2022] Open
Abstract
Humans' remarkable capacity to flexibly adapt their behavior based on rapid situational changes is termed cognitive control. Intuitively, cognitive control is thought to be affected by the state of alertness; for example, when drowsy, we feel less capable of adequately implementing effortful cognitive tasks. Although scientific investigations have focused on the effects of sleep deprivation and circadian time, little is known about how natural daily fluctuations in alertness in the regular awake state affect cognitive control. Here we combined a conflict task in the auditory domain with EEG neurodynamics to test how neural and behavioral markers of conflict processing are affected by fluctuations in alertness. Using a novel computational method, we segregated alert and drowsy trials from two testing sessions and observed that, although participants (both sexes) were generally sluggish, the typical conflict effect reflected in slower responses to conflicting information compared with nonconflicting information, as well as the moderating effect of previous conflict (conflict adaptation), were still intact. However, the typical neural markers of cognitive control-local midfrontal theta-band power changes-that participants show during full alertness were no longer noticeable when alertness decreased. Instead, when drowsy, we found an increase in long-range information sharing (connectivity) between brain regions in the same frequency band. These results show the resilience of the human cognitive control system when affected by internal fluctuations of alertness and suggest that there are neural compensatory mechanisms at play in response to physiological pressure during diminished alertness.SIGNIFICANCE STATEMENT The normal variability in alertness we experience in daily tasks is rarely taken into account in cognitive neuroscience. Here we studied neurobehavioral dynamics of cognitive control with decreasing alertness. We used the classic Simon task where participants hear the word "left" or "right" in the right or left ear, eliciting slower responses when the word and the side are incongruent-the conflict effect. Participants performed the task both while fully awake and while getting drowsy, allowing for the characterization of alertness modulating cognitive control. The changes in the neural signatures of conflict from local theta oscillations to a long-distance distributed theta network suggest a reconfiguration of the underlying neural processes subserving cognitive control when affected by alertness fluctuations.
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Affiliation(s)
- Andrés Canales-Johnson
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Department of Psychology, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Vicerrectoría de Investigación y Posgrado, Universidad Católica del Maule, Talca 3480112, Chile
| | - Lola Beerendonk
- Department of Psychology, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
| | - Salome Blain
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Shin Kitaoka
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Alejandro Ezquerro-Nassar
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Stijn Nuiten
- Department of Psychology, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
| | - Johannes Fahrenfort
- Department of Psychology, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
| | - Simon van Gaal
- Department of Psychology, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
- Amsterdam Brain & Cognition, University of Amsterdam, 1018 WT, Amsterdam, The Netherlands
| | - Tristan A Bekinschtein
- Cambridge Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
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15
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Kim YW, Kim S, Shim M, Jin MJ, Jeon H, Lee SH, Im CH. Riemannian classifier enhances the accuracy of machine-learning-based diagnosis of PTSD using resting EEG. Prog Neuropsychopharmacol Biol Psychiatry 2020; 102:109960. [PMID: 32376342 DOI: 10.1016/j.pnpbp.2020.109960] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/19/2020] [Accepted: 04/30/2020] [Indexed: 12/14/2022]
Abstract
Recently, objective and automated methods for the diagnosis of post-traumatic stress disorder (PTSD) have attracted increasing attention. However, previous studies on machine-learning-based diagnosis of PTSD with resting-state electroencephalogram (EEG) have reported poor accuracies of as low as 60%. Here, a Riemannian geometry-based classifier, the Fisher geodesic minimum distance to the mean (FgMDM), was employed for PTSD classification for the first time. Eyes-closed resting-state EEG data of 39 healthy individuals and 42 PTSD patients were used for the analysis. EEG source activities in 148 cortical regions were parcellated based on the Destrieux atlas, and their covariances were evaluated for each individual. Thirty epochs of preprocessed EEG were employed to calculate source activities. In addition, the FgMDM approach was applied to each EEG source covariance to construct the classifier. For a comparison, linear discriminant analysis (LDA), support vector machine (SVM), and random forest (RF) classifiers employing source band powers and network features as feature candidates were also tested. The FgMDM classifier showed an average classification accuracy of 75.240.80%. In contrast, the maximum accuracies of LDA, SVM, and RF classifiers were 66.54 ± 2.99%, 61.11 ± 2.98%, and 60.99 ± 2.19%, respectively. Our study demonstrated that the diagnostic accuracy of PTSD with resting-state EEG could be significantly improved by employing the FgMDM framework, which is a type of Riemannian geometry-based classifier.
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Affiliation(s)
- Yong-Wook Kim
- Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea; Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea
| | - Sungkean Kim
- Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea; Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea
| | - Miseon Shim
- Department of Psychiatry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Min Jin Jin
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; Department of psychology, Chung-Ang University, Seoul, Republic of Korea
| | - Hyeonjin Jeon
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea
| | - Seung-Hwan Lee
- Clinical Emotion and Cognition Research Laboratory, Inje University, Goyang, Republic of Korea; Department of Psychiatry, Inje University, Ilsan-Paik Hospital, Goyang, Republic of Korea.
| | - Chang-Hwan Im
- Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea.
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16
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Noreika V, Kamke MR, Canales-Johnson A, Chennu S, Bekinschtein TA, Mattingley JB. Alertness fluctuations when performing a task modulate cortical evoked responses to transcranial magnetic stimulation. Neuroimage 2020; 223:117305. [PMID: 32861789 PMCID: PMC7762840 DOI: 10.1016/j.neuroimage.2020.117305] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 07/31/2020] [Accepted: 08/21/2020] [Indexed: 12/21/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) has been widely used in human cognitive neuroscience to examine the causal role of distinct cortical areas in perceptual, cognitive and motor functions. However, it is widely acknowledged that the effects of focal cortical stimulation can vary substantially between participants and even from trial to trial within individuals. Recent work from resting state functional magnetic resonance imaging (fMRI) studies has suggested that spontaneous fluctuations in alertness over a testing session can modulate the neural dynamics of cortical processing, even when participants remain awake and responsive to the task at hand. Here we investigated the extent to which spontaneous fluctuations in alertness during wake-to-sleep transition can account for the variability in neurophysiological responses to TMS. We combined single-pulse TMS with neural recording via electroencephalography (EEG) to quantify changes in motor and cortical reactivity with fluctuating levels of alertness defined objectively on the basis of ongoing brain activity. We observed rapid, non-linear changes in TMS-evoked responses with decreasing levels of alertness, even while participants remained responsive in the behavioural task. Specifically, we found that the amplitude of motor evoked potentials peaked during periods of EEG flattening, whereas TMS-evoked potentials increased and remained stable during EEG flattening and the subsequent occurrence of theta ripples that indicate the onset of NREM stage 1 sleep. Our findings suggest a rapid and complex reorganization of active neural networks in response to spontaneous fluctuations of alertness over relatively short periods of behavioural testing during wake-to-sleep transition.
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Affiliation(s)
- Valdas Noreika
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072, Australia; Cambridge Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom; Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
| | - Marc R Kamke
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072, Australia
| | - Andrés Canales-Johnson
- Cambridge Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom; Vicerrectoría de Investigación y Posgrado, Universidad Católica del Maule, Talca, Chile
| | - Srivas Chennu
- School of Computing, University of Kent, Medway, United Kingdom; Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Tristan A Bekinschtein
- Cambridge Consciousness and Cognition Lab, Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Jason B Mattingley
- Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072, Australia; School of Psychology, University of Queensland, St Lucia, QLD 4072, Australia; Canadian Institute for Advanced Research (CIFAR), Canada
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17
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Peers PV, Astle DE, Duncan J, Murphy FC, Hampshire A, Das T, Manly T. Dissociable effects of attention vs working memory training on cognitive performance and everyday functioning following fronto-parietal strokes. Neuropsychol Rehabil 2020; 30:1092-1114. [PMID: 30569816 PMCID: PMC7266670 DOI: 10.1080/09602011.2018.1554534] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/22/2018] [Indexed: 10/29/2022]
Abstract
Difficulties with attention are common following stroke, particularly in patients with frontal and parietal damage, and are associated with poor outcome. Home-based online cognitive training may have the potential to provide an efficient and effective way to improve attentional functions in such patients. Little work has been carried out to assess the efficacy of this approach in stroke patients, and the lack of studies with active control conditions and rigorous evaluations of cognitive functioning pre and post-training means understanding is limited as to whether and how such interventions may be effective. Here, in a feasibility pilot study, we compare the effects of 20 days of cognitive training using either novel Selective Attention Training (SAT) or commercial Working Memory Training (WMT) programme, versus a waitlist control on a range of attentional and working memory tasks. We demonstrate separable effects of each training condition, with SAT leading to improvements in spatial and non-spatial aspects of attention and WMT leading to improvements on closely related working memory tasks. In addition, both training groups reported improvements in everyday functioning, which were associated with improvements in attention, suggesting that improving attention may be of particular importance in maximising functional improvements in this patient group.
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Affiliation(s)
- Polly V Peers
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Duncan E Astle
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - John Duncan
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Fionnuala C Murphy
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Adam Hampshire
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Tilak Das
- Department of Radiology, Cambridge University Hospitals NHS Trust, Cambridge, UK
| | - Tom Manly
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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18
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Integrity of Corpus Callosum Is Essential for theCross-Hemispheric Propagation of Sleep Slow Waves:A High-Density EEG Study in Split-Brain Patients. J Neurosci 2020; 40:5589-5603. [PMID: 32541070 PMCID: PMC7363462 DOI: 10.1523/jneurosci.2571-19.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/17/2020] [Accepted: 04/19/2020] [Indexed: 11/21/2022] Open
Abstract
The slow waves of non-rapid eye movement (NREM) sleep reflect experience-dependent plasticity and play a direct role in the restorative functions of sleep. Importantly, slow waves behave as traveling waves, and their propagation is assumed to occur through cortico-cortical white matter connections. In this light, the corpus callosum (CC) may represent the main responsible for cross-hemispheric slow-wave propagation. To verify this hypothesis, we performed overnight high-density (hd)-EEG recordings in five patients who underwent total callosotomy due to drug-resistant epilepsy (CPs; two females), in three noncallosotomized neurologic patients (NPs; two females), and in a sample of 24 healthy adult subjects (HSs; 13 females). In all CPs slow waves displayed a significantly reduced probability of cross-hemispheric propagation and a stronger inter-hemispheric asymmetry. In both CPs and HSs, the incidence of large slow waves within individual NREM epochs tended to differ across hemispheres, with a relative overall predominance of the right over the left hemisphere. The absolute magnitude of this asymmetry was greater in CPs relative to HSs. However, the CC resection had no significant effects on the distribution of slow-wave origin probability across hemispheres. The present results indicate that CC integrity is essential for the cross-hemispheric traveling of slow waves in human sleep, which is in line with the assumption of a direct relationship between white matter integrity and slow-wave propagation. Our findings also revealed a residual cross-hemispheric slow-wave propagation that may rely on alternative pathways, including cortico-subcortico-cortical loops. Finally, these data indicate that the lack of the CC does not lead to differences in slow-wave generation across brain hemispheres. SIGNIFICANCE STATEMENT The slow waves of NREM sleep behave as traveling waves, and their propagation has been suggested to reflect the integrity of white matter cortico-cortical connections. To directly assess this hypothesis, here we investigated the role of the corpus callosum in the cortical spreading of NREM slow waves through the study of a rare population of totally callosotomized patients. Our results demonstrate a causal role of the corpus callosum in the cross-hemispheric traveling of sleep slow waves. Additionally, we found that callosotomy does not affect the relative tendency of each hemisphere at generating slow waves. Incidentally, we also found that slow waves tend to originate more often in the right than in the left hemisphere in both callosotomized and healthy adult individuals.
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19
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de Wit MM, Faseyitan O, Coslett HB. Ever-ready for action: Spatial effects on motor system excitability. Cortex 2020; 127:120-130. [PMID: 32172026 DOI: 10.1016/j.cortex.2019.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 11/04/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
Modulation of excitability in the motor system can be observed before overt movements but also in response to covert invitations to act. We asked whether such changes can be induced in the absence of even covert motor instructions, namely, as a function of the location of the hand with reference to the body. Participants received single-pulse TMS over the motor cortex while they placed their contralateral hand (right hand in Experiment 1, left hand in Experiment 2) to the right or left of their body midline, and looked either at or away from their hand. In both experiments, greater excitability was observed when gaze was directed to the right. This finding is interpreted as a consequence of left brain lateralization of motor attention. Contrary to our expectations, we furthermore consistently observed greater excitability when gaze was directed away from the hand. To account for this finding, we introduce the concept of "surveillance attention" which, we speculate, modulates cortical gain, and thereby cortical excitability. Its function is to increase readiness to act in non-foveated regions of space. Such a process confers an advantage in environments, like those in which humans evolved, in which threatening stimuli may appear unexpectedly, and at any time.
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Affiliation(s)
| | - Olufunsho Faseyitan
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - H Branch Coslett
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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20
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Chandrakumar D, Keage HAD, Gutteridge D, Dorrian J, Banks S, Loetscher T. Interactions between spatial attention and alertness in healthy adults: A meta-analysis. Cortex 2019; 119:61-73. [PMID: 31075552 DOI: 10.1016/j.cortex.2019.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/12/2019] [Accepted: 03/18/2019] [Indexed: 11/28/2022]
Abstract
Attending to the visuospatial field is paramount for safety. The inability to sufficiently allocate attention in the environment could lead to unfavourable consequences. One's ability to attend quickly to left- and right-sided stimuli can vary depending on the person's level of alertness. A dominant model of this relationship proposes that low alertness is associated with a rightward bias in attention, with increases in alertness shifting attention leftward. The current study sought to synthesise the literature on spatial attention and alertness and identify modulators of this relationship in healthy adults. Nineteen articles meeting inclusion criteria were identified for meta-analysis. A small effect of alertness on spatial bias (d = .302) with no evidence for a systematic publication bias was found. Of the five investigated modulators, namely, the experimental design relative to alertness, direction of alertness manipulation, measurement of alertness, the nature of the spatial task, and handedness, only the latter was identified as a significant modulator of the relationship between alertness and spatial attention. The review's findings tie in with the influential framework by Corbetta and Shulman (2011) and support the idea to increase alertness as a rehabilitation approach to reduce inattention to the left side in neglect patients. Findings also suggest a need for future research to investigate neurological processes that underlie the alertness and spatial attention relationship, and a need to examine the transfer effects of laboratory-based experiments for real-world implications.
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Affiliation(s)
- Dilushi Chandrakumar
- Cognitive Ageing and Impairment Neurosciences Laboratory, University of South Australia, Australia.
| | - Hannah A D Keage
- Cognitive Ageing and Impairment Neurosciences Laboratory, University of South Australia, Australia
| | - Daria Gutteridge
- Cognitive Ageing and Impairment Neurosciences Laboratory, University of South Australia, Australia
| | - Jill Dorrian
- Sleep and Chronobiology Laboratory, University of South Australia, Australia
| | - Siobhan Banks
- Sleep and Chronobiology Laboratory, University of South Australia, Australia
| | - Tobias Loetscher
- Cognitive Ageing and Impairment Neurosciences Laboratory, University of South Australia, Australia
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21
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Comsa IM, Bekinschtein TA, Chennu S. Transient Topographical Dynamics of the Electroencephalogram Predict Brain Connectivity and Behavioural Responsiveness During Drowsiness. Brain Topogr 2018; 32:315-331. [PMID: 30498872 PMCID: PMC6373294 DOI: 10.1007/s10548-018-0689-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 11/22/2018] [Indexed: 12/20/2022]
Abstract
As we fall sleep, our brain traverses a series of gradual changes at physiological, behavioural and cognitive levels, which are not yet fully understood. The loss of responsiveness is a critical event in the transition from wakefulness to sleep. Here we seek to understand the electrophysiological signatures that reflect the loss of capacity to respond to external stimuli during drowsiness using two complementary methods: spectral connectivity and EEG microstates. Furthermore, we integrate these two methods for the first time by investigating the connectivity patterns captured during individual microstate lifetimes. While participants performed an auditory semantic classification task, we allowed them to become drowsy and unresponsive. As they stopped responding to the stimuli, we report the breakdown of alpha networks and the emergence of theta connectivity. Further, we show that the temporal dynamics of all canonical EEG microstates slow down during unresponsiveness. We identify a specific microstate (D) whose occurrence and duration are prominently increased during this period. Employing machine learning, we show that the temporal properties of microstate D, particularly its prolonged duration, predicts the response likelihood to individual stimuli. Finally, we find a novel relationship between microstates and brain networks as we show that microstate D uniquely indexes significantly stronger theta connectivity during unresponsiveness. Our findings demonstrate that the transition to unconsciousness is not linear, but rather consists of an interplay between transient brain networks reflecting different degrees of sleep depth.
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Affiliation(s)
- Iulia M Comsa
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | | | - Srivas Chennu
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- School of Computing, University of Kent, Medway Building, Chatham Maritime, ME4 4AG, UK.
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22
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Shirazibeheshti A, Cooke J, Chennu S, Adapa R, Menon DK, Hojjatoleslami SA, Witon A, Li L, Bekinschtein T, Bowman H. Placing meta-stable states of consciousness within the predictive coding hierarchy: The deceleration of the accelerated prediction error. Conscious Cogn 2018; 63:123-142. [DOI: 10.1016/j.concog.2018.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/28/2018] [Accepted: 06/07/2018] [Indexed: 01/19/2023]
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23
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Abstract
Changes in the frequency characteristics of EEG alpha rhythm in during falling asleep were studied in three healthy individuals under conditions of long-term isolation (MARS-500 project). Falling asleep was preceded by enhanced alpha rhythm frequency. An inverse correlation between the duration of falling asleep and prevailing alpha rhythm frequency during active and relaxed wakefulness was revealed in the left hemisphere. These results demonstrate the principal possibility of predicting the duration of falling asleep by using alpha rhythm spectral analysis. It is assumed that the frequency of the alpha range spectral peak can be a marker of drowsiness and reflect the current need for sleep.
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An analysis on driver drowsiness based on reaction time and EEG band power. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2015:7982-5. [PMID: 26738144 DOI: 10.1109/embc.2015.7320244] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Falling asleep during driving is a serious problem that has resulted in fatal accidents worldwide. Thus, there is a need to detect driver drowsiness to counter it. This study analyzes the changes in the electroencephalography (EEG) collected from 4 subjects driving under monotonous road conditions using a driving simulator. The drowsiness level of the subjects is inferred from the time taken to react to events. The results from the analysis of the reaction time shows that drowsiness occurs in cycles, which correspond to short sleep cycles known as `microsleeps'. The results from a time-frequency analysis of the four frequency bands' power reveals differences between trials with fast and slow reaction times; greater beta band power is present in all subjects, greater alpha power in 2 subjects, greater theta power in 2 subjects, and greater delta power in 3 subjects, for fast reaction trials. Overall, this study shows that reaction time can be used to infer the drowsiness, and subject-specific changes in the EEG band power may be used to infer drowsiness. Thus the study shows a promising prospect of developing Brain-Computer Interface to detect driver drowsiness.
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25
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Ocular exposure to blue-enriched light has an asymmetric influence on neural activity and spatial attention. Sci Rep 2016; 6:27754. [PMID: 27291291 PMCID: PMC4904199 DOI: 10.1038/srep27754] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/23/2016] [Indexed: 11/13/2022] Open
Abstract
Brain networks subserving alertness in humans interact with those for spatial attention orienting. We employed blue-enriched light to directly manipulate alertness in healthy volunteers. We show for the first time that prior exposure to higher, relative to lower, intensities of blue-enriched light speeds response times to left, but not right, hemifield visual stimuli, via an asymmetric effect on right-hemisphere parieto-occipital α-power. Our data give rise to the tantalising possibility of light-based interventions for right hemisphere disorders of spatial attention.
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26
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Fimm B, Brand T, Spijkers W. Time-of-day variation of visuo-spatial attention. Br J Psychol 2015; 107:299-321. [DOI: 10.1111/bjop.12143] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 06/19/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Bruno Fimm
- Department of Neurology, Section Neuropsychology; RWTH Aachen University; Germany
| | - Tanja Brand
- Department of General Psychiatry; LVR Clinic of Psychiatry and Psychotherapy; Cologne Germany
| | - Will Spijkers
- Institute of Psychology; RWTH Aachen University; Germany
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27
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Bareham CA, Bekinschtein TA, Scott SK, Manly T. Does left-handedness confer resistance to spatial bias? Sci Rep 2015; 5:9162. [PMID: 25781078 PMCID: PMC4361991 DOI: 10.1038/srep09162] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/06/2015] [Indexed: 11/09/2022] Open
Abstract
We recently demonstrated that drowsiness, indexed using EEG, was associated with left-inattention in a group of 26 healthy right-handers. This has been linked to alertness-related modulation of spatial bias in left neglect patients and the greater persistence of left, compared with right, neglect following injury. Despite handedness being among the most overt aspects of human lateralization, studies of this healthy analogue of left neglect have only been conducted with predominantly or exclusively right-handed individuals. Here, with a group of 26 healthy non-right-handers we demonstrate that, unlike right-handers who showed a rightward shift in attention with drowsiness, non-right-handers showed the opposite pattern on an auditory spatial localization task. The current results are the first indication that factors linked to handedness can affect the development and extremity of spatial biases, potentially conferring resilience to clinical symptoms in non-right-handers and, given that 90% of us are right-handed, why left neglect is disproportionately persistent.
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Affiliation(s)
- Corinne A. Bareham
- MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, United Kingdom
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Tristan A. Bekinschtein
- MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, United Kingdom
- Department of Psychology, University of Cambridge, United Kingdom
| | - Sophie K. Scott
- Institute of Cognitive Neuroscience, UCL, London, United Kingdom
| | - Tom Manly
- MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, United Kingdom
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28
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Noreika V, Canales-Johnson A, Koh J, Taylor M, Massey I, Bekinschtein TA. Intrusions of a drowsy mind: neural markers of phenomenological unpredictability. Front Psychol 2015; 6:202. [PMID: 25814962 PMCID: PMC4357244 DOI: 10.3389/fpsyg.2015.00202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 02/09/2015] [Indexed: 11/24/2022] Open
Abstract
The transition from a relaxed to a drowsy state of mind is often accompanied by hypnagogic experiences: most commonly, perceptual imagery, but also linguistic intrusions, i.e., the sudden emergence of unpredictable anomalies in the stream of inner speech. This study has sought to describe the contents of such intrusions, to verify their association with the progression of sleep onset, and to investigate the electroencephalographic processes associated with linguistic intrusions as opposed to more common hypnagogic perceptual imagery. A single participant attended 10 experimental sessions in the EEG laboratory, where he was allowed to drift into a drowsy state of mind, while maintaining metacognition of his own experiences. Once a linguistic intrusion or a noticeable perceptual image occurred, the participant pressed a button and reported it verbally. An increase in the EEG-defined depth of drowsiness as assessed by the Hori system of sleep onset was observed in the last 20 s before a button press. Likewise, EEG Dimension of Activation values decreased before the button press, indicating that the occurrence of cognitively incongruous experiences coincides with the rapid change of EEG predictability patterns. EEG hemispheric asymmetry analysis showed that linguistic intrusions had a higher alpha and gamma power in the left hemisphere electrodes, whereas perceptual imagery reports were associated with a higher beta power over the right hemisphere. These findings indicate that the modality as well as the incongruence of drowsiness-related hypnagogic experiences is strongly associated with distinct EEG signatures in this participant. Sleep onset may provide a unique possibility to study the neural mechanisms accompanying the fragmentation of the stream of consciousness in healthy individuals.
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Affiliation(s)
- Valdas Noreika
- Cognition and Brain Sciences Unit, Medical Research Council Cambridge, UK ; Department of Psychology, University of Cambridge Cambridge, UK
| | - Andrés Canales-Johnson
- Cognition and Brain Sciences Unit, Medical Research Council Cambridge, UK ; Laboratory of Cognitive and Social Neuroscience, Universidad Diego Portales Santiago, Chile
| | - Justin Koh
- Department of Medicine, University of Cambridge Cambridge, UK
| | - Mae Taylor
- Hills Road Sixth Form College Cambridge, UK
| | - Irving Massey
- Departments of English and Comparative Literature, University at Buffalo Buffalo, NY, USA
| | - Tristan A Bekinschtein
- Cognition and Brain Sciences Unit, Medical Research Council Cambridge, UK ; Department of Psychology, University of Cambridge Cambridge, UK
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29
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Charras P, Herbet G, Deverdun J, de Champfleur NM, Duffau H, Bartolomeo P, Bonnetblanc F. Functional reorganization of the attentional networks in low-grade glioma patients: A longitudinal study. Cortex 2015; 63:27-41. [DOI: 10.1016/j.cortex.2014.08.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/27/2014] [Accepted: 08/15/2014] [Indexed: 11/29/2022]
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31
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Linnell KJ, Caparos S, Davidoff J. Urbanization increases left-bias in line-bisection: an expression of elevated levels of intrinsic alertness? Front Psychol 2014; 5:1127. [PMID: 25346707 PMCID: PMC4190999 DOI: 10.3389/fpsyg.2014.01127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 09/16/2014] [Indexed: 11/13/2022] Open
Abstract
Urbanization impairs attentional selection and increases distraction from task-irrelevant contextual information, consistent with a reduction in attentional engagement with the task in hand. Previously, we proposed an attentional-state account of these findings, suggesting that urbanization increases intrinsic alertness and with it exploration of the wider environment at the cost of engagement with the task in hand. Here, we compare urbanized people with a remote people on a line-bisection paradigm. We show that urbanized people have a left spatial bias where remote people have no significant bias. These findings are consistent with the alertness account and provide the first test of why remote peoples have such an extraordinary capacity to concentrate.
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32
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Hartmann M, Martarelli CS, Mast FW, Stocker K. Eye movements during mental time travel follow a diagonal line. Conscious Cogn 2014; 30:201-9. [PMID: 25307523 DOI: 10.1016/j.concog.2014.09.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/10/2014] [Accepted: 09/12/2014] [Indexed: 11/19/2022]
Abstract
Recent research showed that past events are associated with the back and left side, whereas future events are associated with the front and right side of space. These spatial-temporal associations have an impact on our sensorimotor system: thinking about one's past and future leads to subtle body sways in the sagittal dimension of space (Miles, Nind, & Macrae, 2010). In this study we investigated whether mental time travel leads to sensorimotor correlates in the horizontal dimension of space. Participants were asked to mentally displace themselves into the past or future while measuring their spontaneous eye movements on a blank screen. Eye gaze was directed more rightward and upward when thinking about the future than when thinking about the past. Our results provide further insight into the spatial nature of temporal thoughts, and show that not only body, but also eye movements follow a (diagonal) "time line" during mental time travel.
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Affiliation(s)
- Matthias Hartmann
- Department of Psychology, University of Bern, Fabrikstrasse 8, CH-3012 Bern, Switzerland; Division of Cognitive Sciences, University of Potsdam, Germany.
| | - Corinna S Martarelli
- Department of Psychology, University of Bern, Fabrikstrasse 8, CH-3012 Bern, Switzerland
| | - Fred W Mast
- Department of Psychology, University of Bern, Fabrikstrasse 8, CH-3012 Bern, Switzerland
| | - Kurt Stocker
- Department of Psychology, University of Zurich, Binzmühlestrasse 14/25, CH-8050 Zürich, Switzerland
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33
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Kouider S, Andrillon T, Barbosa LS, Goupil L, Bekinschtein TA. Inducing task-relevant responses to speech in the sleeping brain. Curr Biol 2014; 24:2208-2214. [PMID: 25220055 PMCID: PMC4175175 DOI: 10.1016/j.cub.2014.08.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 07/07/2014] [Accepted: 08/08/2014] [Indexed: 10/25/2022]
Abstract
Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment [1]. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep [2]. For instance, sleeping participants can create novel sensory associations between tones and odors [3] or reactivate existing semantic associations, as evidenced by event-related potentials [4-7]. Yet, the extent to which the brain continues to process external stimuli remains largely unknown. In particular, it remains unclear whether sensory information can be processed in a flexible and task-dependent manner by the sleeping brain, all the way up to the preparation of relevant actions. Here, using semantic categorization and lexical decision tasks, we studied task-relevant responses triggered by spoken stimuli in the sleeping brain. Awake participants classified words as either animals or objects (experiment 1) or as either words or pseudowords (experiment 2) by pressing a button with their right or left hand, while transitioning toward sleep. The lateralized readiness potential (LRP), an electrophysiological index of response preparation, revealed that task-specific preparatory responses are preserved during sleep. These findings demonstrate that despite the absence of awareness and behavioral responsiveness, sleepers can still extract task-relevant information from external stimuli and covertly prepare for appropriate motor responses.
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Affiliation(s)
- Sid Kouider
- Laboratoire de Sciences Cognitives et Psycholinguistique, CNRS/EHESS/DEC-ENS, 29 Rue d'Ulm, 75005 Paris, France.
| | - Thomas Andrillon
- Laboratoire de Sciences Cognitives et Psycholinguistique, CNRS/EHESS/DEC-ENS, 29 Rue d'Ulm, 75005 Paris, France; Ecole Doctorale Cerveau-Cognition-Comportement, Université Pierre et Marie Curie, 9 Quai Saint Bernard, 75005 Paris, France
| | - Leonardo S Barbosa
- Laboratoire de Sciences Cognitives et Psycholinguistique, CNRS/EHESS/DEC-ENS, 29 Rue d'Ulm, 75005 Paris, France; Ecole Doctorale Cerveau-Cognition-Comportement, Université Pierre et Marie Curie, 9 Quai Saint Bernard, 75005 Paris, France
| | - Louise Goupil
- Laboratoire de Sciences Cognitives et Psycholinguistique, CNRS/EHESS/DEC-ENS, 29 Rue d'Ulm, 75005 Paris, France; Ecole Doctorale Cerveau-Cognition-Comportement, Université Pierre et Marie Curie, 9 Quai Saint Bernard, 75005 Paris, France
| | - Tristan A Bekinschtein
- Cognition and Brain Sciences Unit, Medical Research Council, 15 Chaucer Road, Cambridge CB2 7EF, UK; Department of Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK
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