The effects of sub-anaesthetic doses of ketamine on memory, cognitive performance and subjective experience in healthy volunteers

Harborne, Giles; Watson, Frances L.; Healy, David; Groves, Lyndsay

doi:10.1177/026988119601000208

Cited by 75 publications

(35 citation statements)

References 22 publications

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“…Ketamine also reduced psychomotor speed on trailmaking in the present study, but did not affect trailmaking scores once psychomotor slowing had been controlled for. This replicates the findings of Harborne et al (1996), and indicates a preservation of some aspects of frontal functioning.…”

Section: Discussionsupporting

confidence: 88%

“…It has been proposed that NMDA-receptor-mediated LTP is involved in both working and long-term memory in humans (Lisman et al, 1998). Indeed ketamine, when administered to healthy volunteers, induces deficits in performance on verbal and visual memory tasks (Adler et al, 1998;Harborne et al, 1996;Harris et al, 1975;Hetem et al, 2000;Krystal et al, 1994Krystal et al, , 1999Krystal et al, , 2000Malhotra et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…While several studies have found ketamine-induced impairments in verbal memory (eg Krystal et al, 1994;Harborne et al, 1996;Malhotra et al, 1996), only one study has investigated the effect of NMDAreceptor antagonism on the episodic memory system (Hetem et al, 2000). Both 'remember' and 'know' responses were reduced following a single dose of ketamine when compared to placebo.…”

Section: Introductionmentioning

confidence: 99%

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Acute Effects of Ketamine on Memory Systems and Psychotic Symptoms in Healthy Volunteers

Morgan

Mofeez

Brandner

et al. 2003

Neuropsychopharmacol

245

174

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N-methyl-D-aspartate (NMDA) receptor antagonists have been demonstrated to induce schizophrenia-like symptoms and cognitive impairment in humans. The NMDA receptor has been strongly implicated in memory, but research to date on the effects of NMDA antagonists has examined only some aspects of human memory functions. This study used a double-blind, placebo-controlled, independent groups design with 54 healthy volunteers to examine the effects of infusions of two doses (0.4, 0.8 mg/kg) of the NMDA antagonist ketamine upon the five human memory systems, aspects of executive functioning and schizophrenia-like and dissociative symptoms. Ketamine produced a dose-dependent impairment to episodic and working memory and a slowing of semantic processing. Ketamine also impaired recognition memory and procedural learning. Attention, perceptual priming and executive functioning were not affected following the drug. In addition, ketamine induced schizophrenia-like and dissociative symptoms, which were not correlated with the cognitive measures. These data suggest that, in humans, ketamine produces a selective pattern of impairments to working, episodic, and procedural memory but not to perceptual priming, attention or aspects of executive functioning.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Acute Effects of Ketamine on Memory Systems and Psychotic Symptoms in Healthy Volunteers

Morgan

Mofeez

Brandner

et al. 2003

Neuropsychopharmacol

245

174

View full text Add to dashboard Cite

show abstract

“…Several studies have reported changes in measures of cognition, eye-tracking, and event-related brain potentials with ketamine in normal (Harborne et al 1996;Radant et al 1998;vanBerckel et al 1998;Oranje et al 2000;Weiler et al 2000) and SVs (LaPorte et al 1996;Malhotra et al 1997a). These results suggest that ketamine, when further studied, may induce additional symptoms of schizophrenia, particularly the cognitive.…”

Section: Discussionmentioning

confidence: 99%

Effects of Ketamine in Normal and Schizophrenic Volunteers

Lahti

Weiler

Michaelidis

et al. 2001

Neuropsychopharmacology

594

355

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“…First, it is hard to see how generalized overactivity can be used to predict the specific changes in context-sensitivity and perceptual grouping emphasized throughout this article. Increases in activity, for Harborne et al (1996). example, as reflected by neuroimaging, are often assumed to be functional, not malfunctional.…”

Section: Nmda-antagonists Impair Cognitive Coordination and Are Schizmentioning

confidence: 99%

Combating fuzziness with computational modeling

Talamini¹,

Meeter²,

Murre³

2003

Behav Brain Sci

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Cognitive neuroscience provides a new conceptual framework for psychiatry by showing how psychological processes arise from neuronal activity (Kandel 1998). Conversely, it is possible that psychiatry will influence the future development of cognitive neuroscience by encouraging a better balance between localist and holistic conceptions of brain function. An apparent conflict between these conceptions has been central to the development of neuroscience, with the emphasis upon locally specialized functions emerging as clearly dominant. Neuroanatomy, neurophysiology, neuropsychology, and neuroimaging all show that different regions of the brain process information about different things, and that different cells within regions deal with different aspects of those things. Recent developments in experimental and theoretical neurobiology, however, are leading to an increased emphasis upon interactions that coordinate the activity of locally specialized processors. Here we argue that impairment of these coor-BEHAVIORAL AND BRAIN SCIENCES (2003) Abstract:The concept of locally specialized functions dominates research on higher brain function and its disorders. Locally specialized functions must be complemented by processes that coordinate those functions, however, and impairment of coordinating processes may be central to some psychotic conditions. Evidence for processes that coordinate activity is provided by neurobiological and psychological studies of contextual disambiguation and dynamic grouping. Mechanisms by which this important class of cognitive functions could be achieved include those long-range connections within and between cortical regions that activate synaptic channels via NMDAreceptors, and which control gain through their voltage-dependent mode of operation. An impairment of these mechanisms is central to PCP-psychosis, and the cognitive capabilities that they could provide are impaired in some forms of schizophrenia. We conclude that impaired cognitive coordination due to reduced ion flow through NMDA-channels is involved in schizophrenia, and we suggest that it may also be involved in other disorders. This perspective suggests several ways in which further research could enhance our understanding of cognitive coordination, its neural basis, and its relevance to psychopathology.Keywords: attention; cerebral cortex; cognitive coordination; cognitive neuropsychiatry; cognitive neuropsychology; context disorganization; Gamma rhythms; Gestalt theory; glutamate; grouping; memory; NMDA-receptors; PCP-psychosis; perceptual organization; schizophrenia William A. Phillips, Ph.D., is Professor of Neuropsychology at the University of Stirling, Scotland UK. He has published more than 70 papers on vision, visual memory, perceptual learning, childrens drawings, the effects of brain damage on reading and writing, and the theory of neuronal computation. He was a founder and the first Director of the Center for Cognitive and Computational Neuroscience at the University of Stirling.Steven M. Silverstein, Ph.D., is A...

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The effects of sub-anaesthetic doses of ketamine on memory, cognitive performance and subjective experience in healthy volunteers

Cited by 75 publications

References 22 publications

Acute Effects of Ketamine on Memory Systems and Psychotic Symptoms in Healthy Volunteers

Acute Effects of Ketamine on Memory Systems and Psychotic Symptoms in Healthy Volunteers

Effects of Ketamine in Normal and Schizophrenic Volunteers

Combating fuzziness with computational modeling

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