Neural response to working memory demand predicts neurocognitive deficits in HIV

Area of Science:

• Neuroscience
• Neurovirology
• Cognitive Psychology

Background:

• Human immunodeficiency virus (HIV) infection can lead to cognitive impairments, including deficits in working memory, attention, and processing speed, despite combined antiretroviral therapy (cART).
• Functional magnetic resonance imaging (fMRI) studies show abnormal brain responses during verbal working memory (VWM) tasks in HIV+ individuals, but the underlying neural mechanisms remain unclear.

Purpose of the Study:

• To investigate the relationship between brain activation patterns during a VWM task and resting-state activity, and their association with neurocognitive performance in HIV+ adults.
• To compare fMRI activation and neuropsychological test results between HIV+ and HIV- (seronegative) adults.

Main Methods:

• Compared fMRI activation during a VWM (n-back) task and resting-state default mode network (DMN) activity in 24 HIV+ and 27 HIV- adults.
• Assessed neurocognitive function using standardized tests for executive control, attention, and processing speed (Stroop, Trail Making A-B) and verbal learning (HVLT-2).

Main Results:

• HIV+ adults exhibited neurocognitive deficits and altered fMRI activation compared to HIV- controls.
• Reduced VWM task-related activation correlated with Stroop interference deficits in HIV+ individuals.
• Resting-state PCC activation was linked to HVLT-2 learning in HIV+ individuals.
• HIV+ adults showed a reduced neural dynamic range (task vs. rest activation), which correlated with both Stroop and HVLT-2 performance.

Conclusions:

• HIV-associated alterations in neural activation during VWM tasks and at rest differentially predict executive-attention and verbal learning deficits.
• Attentional regulation difficulties, specifically in suppressing interference, may contribute to working memory deficits in HIV+ adults.
• Neural dynamic range alterations may serve as a valuable fMRI biomarker for assessing HIV's impact on brain function and predicting cognitive outcomes.