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

Area of Science:

• Neuroscience
• Cognitive Science
• Infectious Disease Research

Background:

• Working memory impairments are a common feature of HIV-associated neurocognitive disorders (HAND).
• The precise origin of these working memory deficits, whether in encoding or maintenance, remains unclear.
• Understanding these origins is crucial for developing targeted interventions.

Purpose of the Study:

• To investigate the spatiotemporal dynamics of working memory processing in HIV-infected individuals.
• To determine whether working memory deficits in HAND are due to impaired encoding or maintenance.
• To identify the neural circuits affected during working memory tasks in HIV infection.

Main Methods:

• A verbal working memory task was administered to HIV-infected adults and demographically-matched controls.
• Magnetoencephalography (MEG) was used to record neural activity during the task.
• Beamforming techniques were employed to image oscillatory neural responses and map brain activity.

Main Results:

• HIV-infected patients exhibited significantly lower accuracy on the working memory task compared to controls.
• Neural activity analysis revealed no group differences during the encoding phase.
• Dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices was observed during the memory maintenance phase in HIV-infected individuals.

Conclusions:

• Working memory impairments in HIV infection are primarily due to deficits in memory maintenance, not encoding.
• These maintenance deficits are associated with abnormal neural activity in specific brain regions.
• Findings highlight the impact of HAND on cognitive function and daily living, emphasizing the need for further research into maintenance-focused interventions.