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Decoupling of sleep-dependent cortical and hippocampal interactions in a neurodevelopmental model of schizophrenia. Neuron 2013; 76:526-33. [PMID: 23141065 PMCID: PMC3898840 DOI: 10.1016/j.neuron.2012.09.016] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2012] [Indexed: 01/02/2023]
Abstract
Rhythmic neural network activity patterns are defining features of sleep, but interdependencies between limbic and cortical oscillations at different frequencies and their functional roles have not been fully resolved. This is particularly important given evidence linking abnormal sleep architecture and memory consolidation in psychiatric diseases. Using EEG, local field potential (LFP), and unit recordings in rats, we show that anteroposterior propagation of neocortical slow-waves coordinates timing of hippocampal ripples and prefrontal cortical spindles during NREM sleep. This coordination is selectively disrupted in a rat neurodevelopmental model of schizophrenia: fragmented NREM sleep and impaired slow-wave propagation in the model culminate in deficient ripple-spindle coordination and disrupted spike timing, potentially as a consequence of interneuronal abnormalities reflected by reduced parvalbumin expression. These data further define the interrelationships among slow-wave, spindle, and ripple events, indicating that sleep disturbances may be associated with state-dependent decoupling of hippocampal and cortical circuits in psychiatric diseases.
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103
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Abstract
Sleep has been described as being of the brain, by the brain, and for the brain. This fundamental neurobiological behavior is controlled by homeostatic and circadian (24-hour) processes and is vital for normal brain function. This review will outline the normal sleep-wake cycle, the changes that occur during aging, and the specific patterns of sleep disturbance that occur in association with both mental health disorders and neurodegenerative disorders. The role of primary sleep disorders such as insomnia, obstructive sleep apnea, and REM sleep behavior disorder as potential causes or risk factors for particular mental health or neurodegenerative problems will also be discussed.
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Affiliation(s)
- Kirstie N Anderson
- Department of Neurology, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle Upon Tyne, UK
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104
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Pritchett D, Wulff K, Oliver PL, Bannerman DM, Davies KE, Harrison PJ, Peirson SN, Foster RG. Evaluating the links between schizophrenia and sleep and circadian rhythm disruption. J Neural Transm (Vienna) 2012; 119:1061-75. [PMID: 22569850 DOI: 10.1007/s00702-012-0817-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 04/20/2012] [Indexed: 12/22/2022]
Abstract
Sleep and circadian rhythm disruption (SCRD) and schizophrenia are often co-morbid. Here, we propose that the co-morbidity of these disorders stems from the involvement of common brain mechanisms. We summarise recent clinical evidence that supports this hypothesis, including the observation that the treatment of SCRD leads to improvements in both the sleep quality and psychiatric symptoms of schizophrenia patients. Moreover, many SCRD-associated pathologies, such as impaired cognitive performance, are routinely observed in schizophrenia. We suggest that these associations can be explored at a mechanistic level by using animal models. Specifically, we predict that SCRD should be observed in schizophrenia-relevant mouse models. There is a rapidly accumulating body of evidence which supports this prediction, as summarised in this review. In light of these emerging data, we highlight other models which warrant investigation, and address the potential challenges associated with modelling schizophrenia and SCRD in rodents. Our view is that an understanding of the mechanistic overlap between SCRD and schizophrenia will ultimately lead to novel treatment approaches, which will not only ameliorate SCRD in schizophrenia patients, but also will improve their broader health problems and overall quality of life.
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Affiliation(s)
- David Pritchett
- Nuffield Department of Clinical Neurosciences-Nuffield Laboratory of Ophthalmology, University of Oxford, John Radcliffe Hospital, Level 5-6 West Wing, Headley Way, Oxford OX3 9DU, UK
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105
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Sleep-related cognitive function and the K-complex in schizophrenia. Behav Brain Res 2012; 234:161-6. [DOI: 10.1016/j.bbr.2012.06.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/15/2012] [Accepted: 06/17/2012] [Indexed: 11/22/2022]
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Abstract
As a partial agonist at the glycine site of the NMDA receptor, D-cycloserine (DCS) has been viewed as lacking potency to fully test the NMDA receptor hypofunction theory of schizophrenia. However, findings of full agonist activity at a subset of NMDA receptors that may have particular relevance to schizophrenia, plus a growing body of evidence demonstrating enhancement of learning and neuroplasticity in animal models, suggest novel therapeutic strategies with DCS in schizophrenia. Preliminary studies with once-weekly administration have supported this potential new role for DCS in schizophrenia by demonstrating benefit for negative symptoms, memory consolidation, and facilitation of cognitive behavioral therapy for delusions.
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Affiliation(s)
- Donald C. Goff
- To whom correspondence should be addressed; Nathan Kline Psychiatric Research Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA; tel: (845) 398-5502, fax: (845) 398-5510, e-mail:
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107
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Da Silva FN, Irani F, Richard J, Brensinger CM, Bilker WB, Gur RE, Gur RC. More than just tapping: index finger-tapping measures procedural learning in schizophrenia. Schizophr Res 2012; 137:234-40. [PMID: 22341487 PMCID: PMC3351528 DOI: 10.1016/j.schres.2012.01.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 01/14/2012] [Accepted: 01/17/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Finger-tapping has been widely studied using behavioral and neuroimaging paradigms. Evidence supports the use of finger-tapping as an endophenotype in schizophrenia, but its relationship with motor procedural learning remains unexplored. To our knowledge, this study presents the first use of index finger-tapping to study procedural learning in individuals with schizophrenia or schizoaffective disorder (SCZ/SZA) as compared to healthy controls. METHODS A computerized index finger-tapping test was administered to 1169 SCZ/SZA patients (62% male, 88% right-handed), and 689 healthy controls (40% male, 93% right-handed). Number of taps per trial and learning slopes across trials for the dominant and non-dominant hands were examined for motor speed and procedural learning, respectively. RESULTS Both healthy controls and SCZ/SZA patients demonstrated procedural learning for their dominant hand but not for their non-dominant hand. In addition, patients showed a greater capacity for procedural learning even though they demonstrated more variability in procedural learning compared to healthy controls. Left-handers of both groups performed better than right-handers and had less variability in mean number of taps between non-dominant and dominant hands. Males also had less variability in mean tap count between dominant and non-dominant hands than females. As expected, patients had a lower mean number of taps than healthy controls, males outperformed females and dominant-hand trials had more mean taps than non-dominant hand trials in both groups. CONCLUSIONS The index finger-tapping test can measure both motor speed and procedural learning, and motor procedural learning may be intact in SCZ/SZA patients.
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Affiliation(s)
- Felipe N. Da Silva
- Brain Behavior Laboratory, Section of Neuropsychiatry, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4283, United States
| | - Farzin Irani
- Brain Behavior Laboratory, Section of Neuropsychiatry, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4283, United States
| | - Jan Richard
- Brain Behavior Laboratory, Section of Neuropsychiatry, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4283, United States
| | - Colleen M. Brensinger
- Department of Biostatistics, University of Pennsylvania, Philadelphia, PA 19104-4283, United States
| | - Warren B. Bilker
- Department of Biostatistics, University of Pennsylvania, Philadelphia, PA 19104-4283, United States
| | - Raquel E. Gur
- Brain Behavior Laboratory, Section of Neuropsychiatry, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4283, United States
| | - Ruben C. Gur
- Brain Behavior Laboratory, Section of Neuropsychiatry, Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4283, United States
- Philadelphia Veterans Administration Medical Center, Philadelphia, PA 19104-4283, United States
- Corresponding author: Ruben C. Gur. Present/Permanent Address: Brain Behavior Laboratory, Department of Psychiatry, 10th floor Gates Building, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA, 19104-4283, United States. Tel.: +1 215 615 3604; fax: +1 215 662 7903.
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108
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Wamsley EJ, Tucker MA, Shinn AK, Ono KE, McKinley SK, Ely AV, Goff DC, Stickgold R, Manoach DS. Reduced sleep spindles and spindle coherence in schizophrenia: mechanisms of impaired memory consolidation? Biol Psychiatry 2012; 71:154-61. [PMID: 21967958 PMCID: PMC3561714 DOI: 10.1016/j.biopsych.2011.08.008] [Citation(s) in RCA: 311] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 07/15/2011] [Accepted: 08/13/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Sleep spindles are thought to induce synaptic changes and thereby contribute to memory consolidation during sleep. Patients with schizophrenia show dramatic reductions of both spindles and sleep-dependent memory consolidation, which may be causally related. METHODS To examine the relations of sleep spindle activity to sleep-dependent consolidation of motor procedural memory, 21 chronic, medicated schizophrenia outpatients and 17 healthy volunteers underwent polysomnography on two consecutive nights. On the second night, participants were trained on the finger-tapping motor sequence task (MST) at bedtime and tested the following morning. The number, density, frequency, duration, amplitude, spectral content, and coherence of stage 2 sleep spindles were compared between groups and examined in relation to overnight changes in MST performance. RESULTS Patients failed to show overnight improvement on the MST and differed significantly from control participants who did improve. Patients also exhibited marked reductions in the density (reduced 38% relative to control participants), number (reduced 36%), and coherence (reduced 19%) of sleep spindles but showed no abnormalities in the morphology of individual spindles or of sleep architecture. In patients, reduced spindle number and density predicted less overnight improvement on the MST. In addition, reduced amplitude and sigma power of individual spindles correlated with greater severity of positive symptoms. CONCLUSIONS The observed sleep spindle abnormalities implicate thalamocortical network dysfunction in schizophrenia. In addition, the findings suggest that abnormal spindle generation impairs sleep-dependent memory consolidation in schizophrenia, contributes to positive symptoms, and is a promising novel target for the treatment of cognitive deficits in schizophrenia.
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Affiliation(s)
- Erin J. Wamsley
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, Harvard Medical School, Boston, MA, 02215
| | - Matthew A. Tucker
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, Harvard Medical School, Boston, MA, 02215
| | - Ann K. Shinn
- Psychotic Disorders Division, McLean Hospital, Belmont, MA 02478
| | - Kim E. Ono
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129
| | - Sophia K. McKinley
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, Harvard Medical School, Boston, MA, 02215
| | - Alice V. Ely
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, Harvard Medical School, Boston, MA, 02215
| | - Donald C. Goff
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129
| | - Robert Stickgold
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, Harvard Medical School, Boston, MA, 02215
| | - Dara S. Manoach
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129
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109
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Abstract
AbstractSchizophrenia is a disorder characterized by a variety of symptoms, which among others include hallucinations, delusions and passivity experiences. It has been found that individuals with schizophrenia misattribute their own thoughts and actions to an outside agency (source monitoring deficits), which could account for psychotic experiences such as that of hearing voices. In order to explain the source-monitoring deficits as well as psychosis, it has been proposed that mechanisms that enable anticipation and recognition of sensory consequences of one’s own actions are impaired in schizophrenia. Importantly, such mechanisms may require accurate cortical sensory representations such as in the primary somatosensory cortex (S1). The establishment and maintenance of cortical sensory representations has been found to utilize a sleep-related brain rhythm known as spindling. Namely, in the perinatal period in humans and animals, and possibly also thereafter, spontaneous activity in the sensory periphery drives spindle activity in the developing cortical sensory areas, which then contributes to the formation of sensory representations that match bodily features. For example, muscle twitch-spindle sequences during sleep facilitate the formation and maintenance of S1 in accordance with the layout of musculature. This process has been proposed to continue throughout the lifespan and may be particularly important during periods of bodily changes (adolescence, menopause). In schizophrenia, the amount of sleep spindle activity is markedly reduced, which would be expected to result in insufficient cortical sensory representations and have relevance for the relative inability of individuals with schizophrenia to accurately recognize self-initiated actions.
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111
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Similarities between cortical “up” states during slow wave sleep and wakefulness: the implications for schizophrenia. Transl Neurosci 2012. [DOI: 10.2478/s13380-012-0004-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractNegative and positive symptoms are defining features of schizophrenia. This illness is commonly associated with a number of cognitive and affective deficits as well as with some more specific sleep abnormalities. It has been previously proposed that psychosis and positive symptoms in schizophrenia could be understood as disorders of internal brain dynamics. This proposed disordered network interplay might be particularly displayed during sleep when modulation by the senses is at the minimum. It is argued here that sleep abnormalities in schizophrenia inform our understanding of the pathomechanisms involved in psychosis. More specifically, sleep spindle initiation in NREM sleep and the preparation of sensory pathways for upcoming motor actions during wakefulness may share a common mechanism, and this shared mechanism is suggested to be impaired in schizophrenia.
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112
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D'Agostino A, Limosani I, Scarone S. The dreaming brain/mind: a role in understanding complex mental disorders? Front Psychiatry 2012; 3:3. [PMID: 22319501 PMCID: PMC3269040 DOI: 10.3389/fpsyt.2012.00003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/09/2012] [Indexed: 11/18/2022] Open
Affiliation(s)
- Armando D'Agostino
- Department of Medicine, Surgery and Dentistry, Università degli Studi di Milano Milan, Italy
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113
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Prehn-Kristensen A, Molzow I, Munz M, Wilhelm I, Müller K, Freytag D, Wiesner CD, Baving L. Sleep restores daytime deficits in procedural memory in children with attention-deficit/hyperactivity disorder. RESEARCH IN DEVELOPMENTAL DISABILITIES 2011; 32:2480-2488. [PMID: 21820271 DOI: 10.1016/j.ridd.2011.06.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 06/24/2011] [Indexed: 05/31/2023]
Abstract
Sleep supports the consolidation of declarative and procedural memory. While prefrontal cortex (PFC) activity supports the consolidation of declarative memory during sleep, opposite effects of PFC activity are reported with respect to the consolidation of procedural memory during sleep. Patients with attention-deficit/hyperactivity disorder (ADHD) are characterised by a prefrontal hypoactivity. Therefore, we hypothesised that children with ADHD benefit from sleep with respect to procedural memory more than healthy children. Sixteen children with ADHD and 16 healthy controls (aged 9-12) participated in this study. A modification of the serial-reaction-time task was conducted. In the sleep condition, learning took place in the evening and retrieval after a night of sleep, whereas in the wake condition learning took place in the morning and retrieval in the evening without sleep. Children with ADHD showed an improvement in motor skills after sleep compared to the wake condition. Sleep-associated gain in reaction times was positively correlated with the amount of sleep stage 4 and REM-density in ADHD. As expected, sleep did not benefit motor performance in the group of healthy children. These data suggest that sleep in ADHD normalizes deficits in procedural memory observed during daytime. It is discussed whether in patients with ADHD attenuated prefrontal control enables sleep-dependent gains in motor skills by reducing the competitive interference between explicit and implicit components within a motor task.
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Affiliation(s)
- Alexander Prehn-Kristensen
- Center for Integrative Psychiatry, Department of Child and Adolescent Psychiatry and Psychotherapy, Christian-Albrechts-University School of Medicine, 24105 Kiel, Germany.
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Vukadinovic Z. Sleep abnormalities in schizophrenia may suggest impaired trans-thalamic cortico-cortical communication: towards a dynamic model of the illness. Eur J Neurosci 2011; 34:1031-9. [PMID: 21895800 DOI: 10.1111/j.1460-9568.2011.07822.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Schizophrenia is associated with a wide range of symptoms. These include auditory hallucinations, delusions, and experiences that one is not in control of one's own thoughts and actions, but that they are inserted by an outside agency. It has been proposed that a disturbance in the sense of self may account for many of these symptoms. This disturbance in turn may be associated with source monitoring deficits. In other words, individuals with schizophrenia may misattribute the source of their own thoughts and actions to an outside agency, which then results in the experience of psychosis such as that of hearing voices. To explain the source monitoring deficits, it has been proposed that this illness involves impairment in corollary discharge mechanisms. Corollary discharge refers to preparation of sensory systems that will be affected by an action in advance of that action, which then allows this action to be recognized as one's own. Current research on corollary discharges suggests that they may involve the thalamus, which is notably affected in schizophrenia in terms of volume loss. Sleep abnormalities in this illness also suggest thalamic dysfunction as sleep spindles, which are markedly reduced in schizophrenia, require intact thalamocortical interactions. In this review, evidence is presented that suggests that propagation of corollary discharges and sleep spindles may be two mechanistically related processes as both involve trans-thalamic cortico-cortical interactions. These interactions may be impaired in schizophrenia and characterization of their mechanism may constitute a step towards developing a dynamic model of schizophrenia.
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Affiliation(s)
- Zoran Vukadinovic
- Montefiore Medical Center, Albert Einstein College of Medicine, Department of Psychiatry and Behavioral Sciences, Residency Training Program, Bronx, NY, USA.
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115
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Genzel L, Ali E, Dresler M, Steiger A, Tesfaye M. Sleep-dependent memory consolidation of a new task is inhibited in psychiatric patients. J Psychiatr Res 2011; 45:555-60. [PMID: 20869069 DOI: 10.1016/j.jpsychires.2010.08.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 08/25/2010] [Accepted: 08/27/2010] [Indexed: 11/27/2022]
Abstract
Schizophrenic and depressive patients show impeded sleep-dependent procedural memory consolidation. But this has been shown mainly for tasks testing the adaptation of old skills. This study tested the overnight memory consolidation of a new task and the transfer of this new skill to a similar task. Using an adapted version of the sequential finger tapping task, keyboard-naïve Ethiopian depressive (n = 8) and schizophrenic (n = 15) patients and healthy controls (n = 11 and n = 17) were tested twice, 24 h apart. In addition the subjects underwent training in a second sequence after the retest of the first sequence. Both schizophrenic and depressive patients did not show a significant overnight change in performance (1% and 4% improvement respectively) in the task and differed significantly from the healthy control groups who did show significant improvement (16% and 22%). Further in contrast to the healthy controls both patients groups showed no significant transfer of the newly acquired skill to the second sequence. This study shows that depressive and schizophrenic patients are not only deficient in the overnight memory consolidation of a new task, but also fail to show a transfer of this new skill to similar tasks.
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Affiliation(s)
- Lisa Genzel
- Department of Psychiatry, Max Planck Institute of Psychiatry, Kraepelinstr. 2-10, 80804 Munich, Germany.
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116
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Abstract
OBJECTIVES To determine whether sleep benefits motor memory in healthy elderly adults and, if so, whether the observed sleep-related benefits are comparable with those observed in healthy young adults. DESIGN Repeated-measures cross-over design. SETTING Boston, Massachusetts (general community) and Harvard University. PARTICIPANTS Sixteen healthy older and 15 healthy young participants. MEASUREMENTS Motor sequence task (MST) performance was assessed at training and at the beginning and end of the retest session; polysomnographic sleep studies were recorded for the elderly participants. RESULTS After 12 hours of daytime wakefulness, elderly participants showed a dramatic decline in MST performance on the first three retest trials, and only a nonsignificant improvement by the end of retest (the last 3 retest trials). In contrast, when the same participants trained in the morning but were retested 24 hours after training, after a day of wake plus a night of sleep, they maintained their performance at the beginning of retest and demonstrated a highly significant 17.4% improvement by the end of the retest session, essentially identical to the 17.3% improvement seen in young participants. These strikingly similar improvements occurred despite the presence of other age-related differences, including overall slower motor speed, a lag in the appearance of sleep-dependent improvement, and an absence of correlations between overnight improvement and sleep architecture or sleep spindle density in the elderly participants. CONCLUSION These findings provide compelling evidence that sleep optimizes motor skill performance across the adult life span.
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Affiliation(s)
- Matthew Tucker
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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118
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Göder R, Seeck-Hirschner M, Stingele K, Huchzermeier C, Kropp C, Palaschewski M, Aldenhoff J, Koch J. Sleep and cognition at baseline and the effects of REM sleep diminution after 1 week of antidepressive treatment in patients with depression. J Sleep Res 2011; 20:544-51. [PMID: 21352389 DOI: 10.1111/j.1365-2869.2011.00914.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Robert Göder
- Department of Psychiatry and Psychotherapy, Christian Albrechts University, University Hospital Schleswig-Holstein, Niemannsweg, Kiel, Germany.
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119
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Abstract
Most complex psychiatric disorders cannot be explained by pathology of a single brain region, but arise as a consequence of dysfunctional interactions between brain regions. Schizophrenia, in particular, has been described as a 'disconnection syndrome', but similar principles are likely to apply to depression and ADHD (attention deficit hyperactivity disorder). All these diseases are associated with impaired co-ordination of neural population activity, which manifests as abnormal EEG (electroencephalogram) and LFP (local field potential) oscillations both within and across subcortical and cortical brain regions. Importantly, it is increasingly possible to link oscillations and interactions at distinct frequencies to the physiology and/or pathology of distinct classes of neurons and interneurons. Such analyses increasingly implicate abnormal levels, timing or modulation of GABA (gamma-aminobutyric acid)-ergic inhibition in brain disease. The present review discusses the evidence suggesting that dysfunction of a particular class of interneurons, marked by their expression of the calcium-binding protein parvalbumin, could contribute to the broad range of neurophysiological and behavioural symptoms characteristic of schizophrenia.
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120
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Manoach DS, Stickgold R. Does abnormal sleep impair memory consolidation in schizophrenia? Front Hum Neurosci 2009; 3:21. [PMID: 19750201 PMCID: PMC2741296 DOI: 10.3389/neuro.09.021.2009] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 08/12/2009] [Indexed: 11/13/2022] Open
Abstract
Although disturbed sleep is a prominent feature of schizophrenia, its relation to the pathophysiology, signs, and symptoms of schizophrenia remains poorly understood. Sleep disturbances are well known to impair cognition in healthy individuals. Yet, in spite of its ubiquity in schizophrenia, abnormal sleep has generally been overlooked as a potential contributor to cognitive deficits. Amelioration of cognitive deficits is a current priority of the schizophrenia research community, but most efforts to define, characterize, and quantify cognitive deficits focus on cross-sectional measures. While this approach provides a valid snapshot of function, there is now overwhelming evidence that critical aspects of learning and memory consolidation happen offline, both over time and with sleep. Initial memory encoding is followed by a prolonged period of consolidation, integration, and reorganization, that continues over days or even years. Much of this evolution of memories is mediated by sleep. This article briefly reviews (i) what is known about abnormal sleep in schizophrenia, (ii) sleep-dependent memory consolidation in healthy individuals, (iii) recent findings of impaired sleep-dependent memory consolidation in schizophrenia, and (iv) implications of impaired sleep-dependent memory consolidation in schizophrenia. This literature suggests that abnormal sleep in schizophrenia disrupts attention and impairs sleep-dependent memory consolidation and task automation. We conclude that these sleep-dependent impairments may contribute substantially to generalized cognitive deficits in schizophrenia. Understanding this contribution may open new avenues to ameliorating cognitive dysfunction and thereby improve outcome in schizophrenia.
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Affiliation(s)
- Dara S Manoach
- Department of Psychiatry, Massachusetts General Hospital Charlestown, MA 02129 , USA.
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