Aberrant Neuronal Dynamics during Working Memory Operations in the Aging HIV-Infected Brain

Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation direc...

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Bibliographic Details
Published in:Scientific reports 2017-02, Vol.7 (1), p.41568-41568, Article 41568
Main Authors: Wilson, Tony W., Proskovec, Amy L., Heinrichs-Graham, Elizabeth, O’Neill, Jennifer, Robertson, Kevin R., Fox, Howard S., Swindells, Susan
Format: Article
Language:English
Subjects:
631/378/1689/132
692/617/375/1367
Cerebellum
Circuits
Cognition
Hippocampus
Humanities and Social Sciences
Magnetoencephalography
Memory
Mental task performance
multidisciplinary
Older people
Science
Short term memory
Synchronization
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Summary:Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG). Significant oscillatory neural responses were imaged using a beamforming approach to illuminate the spatiotemporal dynamics of neuronal activity. HIV-infected patients were significantly less accurate on the working memory task and their neuronal dynamics indicated that encoding operations were preserved, while memory maintenance processes were abnormal. Specifically, no group differences were detected during the encoding period, yet dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices emerged during memory maintenance. In addition, task performance in the controls covaried with occipital alpha synchronization and activity in right prefrontal cortices. In conclusion, working memory impairments are common and significantly impact the daily functioning and independence of HIV-infected patients. These impairments likely reflect deficits in the maintenance of memory representations, not failures to adequately encode stimuli.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep41568