Sparing of attentional relative to mnemonic function in a subgroup of patients with dementia of the Alzheimer type

Sahakian, Barbara J.; Downes, John J.; Eagger, Sarah; Evenden, J. L.; Levy, Raymond; Philpot, Michael; Roberts, Angela; Robbins, Trevor W.

doi:10.1016/0028-3932(90)90055-s

Cited by 143 publications

(87 citation statements)

References 41 publications

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“…The task involves learning to associate visual stimuli with distinct spatial locations on a trial-by-trial basis, performance of which has been demonstrated to decline with age in large-sample factor analytic studies (Rabbitt and Lowe 2000;Robbins et al 1994). Sahakian and colleagues have further demonstrated impaired performance of vsPAL in AD patients relative to age-and premorbid IQ-matched controls, and recognition-memory impaired Parkinson's patients (Sahakian et al 1990;Sahakian et al 1988;Sahgal et al 1991). Recent prospective investigations based on these findings have provided additional confirmation that the vsPAL task is particularly sensitive to, and specific for, symptoms of neurocognitive decline associated with AD.…”

Section: Introductionmentioning

confidence: 94%

Differential muscarinic and NMDA contributions to visuo-spatial paired-associate learning in rhesus monkeys

et al. 2002

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Rationale-Early, accurate detection of degenerative neurological disorders such as Alzheimer's Disease (AD) is essential for therapies designed to slow disease progression. Performance of a touch-screen mediated visuo-spatial paired-associates learning (vsPAL) task predicts neurocognitive decline in elderly populations presenting with mild cognitive impairment and distinguishes AD patients from elderly depressed individuals. Translation of this cognitive task to a nonhuman model may therefore provide an improved tool for study of the etiology and treatment of dementia.Objective-The goal of the current study was to contrast cholinergic and glutamatergic contributions to performance of this AD-sensitive task by challenging rhesus monkeys performing vsPAL with muscarinic antagonist and non-competitive NMDA antagonist drugs.Methods-Monkeys (7) were trained to perform vsPAL and then serially challenged with acute doses of scopolamine (3, 10, 17 µg/kg, i.m.) and ketamine (0.3, 1.0, 1.78 mg/kg, i.m.).Results-Scopolamine produced a dose × difficulty related impairment of both recognition memory and incremental acquisition aspects of task performance. In contrast, ketamine administration resulted in a dose-dependent impairment of recognition memory but not incremental acquisition.Conclusions-Monkeys' performance of a task sensitive to AD in humans was impaired by two classic pharmacological models of cognitive impairment therefore supporting the use of this nonhuman model to explore mechanisms of AD-associated cognitive decline. The differential pattern of impairment observed is consistent with a hypothesis that muscarinic mechanisms are required for linking external events with an existing internal representation, whereas NMDA mechanisms are required for the formation/strengthening of such an internal representation.

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Section: Introductionmentioning

confidence: 94%

Differential muscarinic and NMDA contributions to visuo-spatial paired-associate learning in rhesus monkeys

et al. 2002

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“…The CANTAB is designed with a significant focus on neuropsychological functions, subserved by frontal lobe regions, such as frontostriatal circuitry that mediate motor, cognitive and behavioral functions within the brain (Fray, Robbins, & Sahakian, 1996). It has been extensively validated for assessing brain-behavior relationships and is sensitive to detect brain dysfunctions in the frontal, temporal, and amygdalo-hippocampal regions (Clark, Chamberlain, & Sahakian, 2009;Owen, Sahakian, Semple, Polkey, & Robbins, 1995;Sahakian et al, 1990).…”

Section: Cognitive Assessmentmentioning

confidence: 99%

“…We suggest this specific design to be more helpful in interpreting results, as it is based on a research hypothesis derived from neuropsychological and neuroimaging findings of the PFC, and considers both the left and right DLFPC. Also, we used a series of cognitive assessment measures that are sensitive to cortical functions and are designed with a focus on neuropsychological functions of frontal lobe regions in depression (Egerhazi et al, 2013;Sahakian et al, 1990). Finally, this study aims to examine visual aspects of memory, which is one of the most impaired cognitive domains in MD (Egerhazi et al, 2013;Sahakian et al, 1990); yet to date no tDCS studies have investigated effects of brain stimulation on visual memory in MD.…”

Section: Introductionmentioning

confidence: 99%

Transcranial Direct Current Stimulation of Dorsolateral Prefrontal Cortex of Major Depression: Improving Visual Working Memory, Reducing Depressive Symptoms

Salehinejad

Rostami²,

Ghanavati³

2015

NeuroRegulation

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Recent studies on major depression (MD) have used noninvasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) to improve impaired emotion and cognition in MD. However, such experiments have yielded mixed results, specifically with respect to cognition in MD. This study aimed to investigate whether anodal and cathodal tDCS applied over the dorsolateral prefrontal cortex (DLPFC) would significantly improve visual working memory and reduce depressive symptoms in patients with MD. Thirty patients with major depression (n = 30) were randomly assigned to receive either experimental (active) or control (sham) tDCS. To measure cognitive functions, the participants underwent a series of visual memory neuropsychological tasks; and to measure depression symptoms, the Beck Depression Inventory (BDI) and Hamilton Depression Scale (HDRS) were used. The parameters of active tDCS included 2 mA for 20 min per day for 10 consecutive days, anode over the left DLPFC (F3), cathode over the right DLPFC (F4) region. After 10 sessions of anodal and cathodal tDCS, patients showed significantly improved performance in visual working memory tasks. The same results were observed for depression symptoms. This study showed that anodal tDCS over left DLPFC, concurrently with cathodal tDCS over right DLPFC, improved cognitive impairment (specifically visual working memory), as well as reduced depressive symptoms in patients with MD. This finding provides evidence that supports effectiveness of a specific montage of tDCS to improve impaired cognition in MD, specifically in visual working memory.

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“…The computerized attentional set-shifting paradigm has also been described in detail elsewhere (Downes et ai, 1989;Sahakian et al, 1990;Owen el ai, 1991). The subject was required to learn a series of discriminations in which one of two stimulus dimensions was relevant and the other was not, using feedback provided automatically by the computer.…”

Section: Attentional Set-shifting Testmentioning

confidence: 99%

Fronto-Striatal Cognitive Deficits at Different Stages of Parkinson's Disease

Owen

James

Leigh

et al. 1992

Brain

819

525

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Sparing of attentional relative to mnemonic function in a subgroup of patients with dementia of the Alzheimer type

Cited by 143 publications

References 41 publications

Differential muscarinic and NMDA contributions to visuo-spatial paired-associate learning in rhesus monkeys

Differential muscarinic and NMDA contributions to visuo-spatial paired-associate learning in rhesus monkeys

Transcranial Direct Current Stimulation of Dorsolateral Prefrontal Cortex of Major Depression: Improving Visual Working Memory, Reducing Depressive Symptoms

Fronto-Striatal Cognitive Deficits at Different Stages of Parkinson's Disease

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