Impaired Processing of Serial Order Determines Working Memory Impairments in Alzheimer’s Disease

This study examines the enactment effect in early Alzheimer’s disease using a novel working memory task. Free recall of action-object instruction sequences was measured in individuals with Alzheimer’s disease (n=14) and older adult controls (n=15). Instruction sequences were read out loud by the experimenter (verbal-only task) or read by the experimenter and performed by the participants (subject-performed task). In both groups and for all sequence lengths, recall was superior in the subject-performed condition than the verbal-only condition. Individuals with Alzheimer’s disease showed a deficit in free recall of recently learned instruction sequences relative to older adult controls, yet both groups show a significant benefit from performing actions themselves at encoding. The subject-performed task shows promise as a tool to improve working memory in early Alzheimer’s disease.

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Chronic stress accelerates learning and memory impairments and increases amyloid deposition in APP V717I ‐CT100 transgenic mice, an Alzheimer's disease model

The FASEB Journal ◽

10.1096/fj.05-4265fje ◽

2006 ◽

Vol 20 (6) ◽

pp. 729-731 ◽

Cited By ~ 146

Author(s):

Yun Ha Jeong ◽

Cheol Hyoung Park ◽

Jongman Yoo ◽

Ki Young Shin ◽

Sung‐Min Ahn ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Transgenic Mice ◽

Learning And Memory ◽

Chronic Stress ◽

Disease Model ◽

Amyloid Deposition ◽

Memory Impairments

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Effect of Letrozole on hippocampal let-7 microRNAs and their correlation with working memory and phosphorylated Tau protein level in an Alzheimer's disease rat model

10.21203/rs.3.rs-444685/v1 ◽

2021 ◽

Author(s):

Nada Alaa Moustafa ◽

Mohammed Abdelhamed El-Sayed ◽

Somia Hassan Abdallah ◽

Noha M. Hazem ◽

Doaa Attia Abdelmoety

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Working Memory ◽

Tau Protein ◽

Sprague Dawley ◽

Qrt Pcr ◽

Sprague Dawley Rats ◽

Conflicting Evidence ◽

With Memory ◽

Phosphorylated Tau Protein

Abstract Let-7 microRNAs may contribute to neurodegeneration, including Alzheimer's disease (AD), but, they were not investigated in Streptozotocin (STZ)-induced AD. Letrozole increases the expression of Let-7 in cell lines, with conflicting evidence regarding its effects on memory. This study examined Let-7 microRNAs in STZ-induced AD, their correlation with memory and hyperphosphorylated Tau (p-Tau) and the effects of Letrozole on them. Seven groups of adult Sprague Dawley rats were used: Intact, Letrozole, Letrozole Vehicle, STZ (with AD induced by intracerebroventricular injection of STZ in artificial CSF), CSF Control, STZ + Letrozole (STZ-L), and CSF + Letrozole Vehicle. Alternation percentage in T-maze was used as a measure of working memory. Let-7a, b and e and p-Tau levels in the hippocampus were estimated using qRT-PCR and ELISA, respectively. There were significant decreases in alternation percentage and increase in p-Tau in the STZ, Letrozole and STZ-L groups. Expression levels of all studied microRNAs were significantly elevated in the Letrozole and the STZ + L groups, with no difference between the two, suggesting that this elevation was due to Letrozole. Negative correlations were found between alternation percentage and the levels of all studied microRNAs, while positive ones were found between p-Tau concentration and the levels of studied microRNAs. These findings support the theory that Letrozole aggravates pre-existing lesions and add to the evidence of Let-7 neurotoxicity.

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Working Memory and Executive Function Decline across Normal Aging, Mild Cognitive Impairment, and Alzheimer’s Disease

BioMed Research International ◽

10.1155/2015/748212 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 137

Author(s):

Anna-Mariya Kirova ◽

Rebecca B. Bays ◽

Sarita Lagalwar

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Working Memory ◽

Cognitive Impairment ◽

Executive Function ◽

Mild Cognitive Impairment ◽

Executive Dysfunction ◽

Normal Aging ◽

Future Research ◽

Neurological Differences

Alzheimer’s disease (AD) is a progressive neurodegenerative disease marked by deficits in episodic memory, working memory (WM), and executive function. Examples of executive dysfunction in AD include poor selective and divided attention, failed inhibition of interfering stimuli, and poor manipulation skills. Although episodic deficits during disease progression have been widely studied and are the benchmark of a probable AD diagnosis, more recent research has investigated WM and executive function decline during mild cognitive impairment (MCI), also referred to as the preclinical stage of AD. MCI is a critical period during which cognitive restructuring and neuroplasticity such as compensation still occur; therefore, cognitive therapies could have a beneficial effect on decreasing the likelihood of AD progression during MCI. Monitoring performance on working memory and executive function tasks to track cognitive function may signal progression from normal cognition to MCI to AD. The present review tracks WM decline through normal aging, MCI, and AD to highlight the behavioral and neurological differences that distinguish these three stages in an effort to guide future research on MCI diagnosis, cognitive therapy, and AD prevention.

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Emotional Working Memory and Alzheimer’s Disease

International Journal of Alzheimer s Disease ◽

10.1155/2014/207698 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Nicola Mammarella ◽

Beth Fairfield

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Working Memory ◽

Memory Performance ◽

Memory Task ◽

Emotional Information ◽

Healthy Older Adults ◽

Affective Stimuli ◽

Age Related ◽

Dementia Of Alzheimer’S Type

A number of recent studies have reported that working memory does not seem to show typical age-related deficits in healthy older adults when emotional information is involved. Differently, studies about the short-term ability to encode and actively manipulate emotional information in dementia of Alzheimer’s type are few and have yielded mixed results. Here, we review behavioural and neuroimaging evidence that points to a complex interaction between emotion modulation and working memory in Alzheimer’s. In fact, depending on the function involved, patients may or may not show an emotional benefit in their working memory performance. In addition, this benefit is not always clearly biased (e.g., towards negative or positive information). We interpret this complex pattern of results as a consequence of the interaction between multiple factors including the severity of Alzheimer’s disease, the nature of affective stimuli, and type of working memory task.

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