Adaptation of the attention network in human immunodeficiency virus brain injury.
Human immunodeficiency virus (HIV)-positive patients commonly have attention and concentration problems. However, it remains unclear how HIV infection affects the attention network. Therefore, blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) was performed in 36 subjects (18 HIV and 18 seronegative [SN] controls) during a set of visual attention tasks with increasing levels of attentional load. Compared with SN controls, HIV subjects showed similar task performance (accuracies and reaction times) but decreased activation in the normal visual attention network (dorsal parietal, bilateral prefrontal, and cerebellar regions) and increased activation in adjacent or contralateral brain regions. Cognitive performance (assessed with NPZ-8), CD4, and viral load all correlated with activated BOLD signals in brain regions that activated more in HIV subjects. Furthermore, HIV subjects activated more than SN controls in brain regions that showed load-dependent increase in activation (right prefrontal and right parietal regions) but less in regions that showed a saturation effect with increasing load. These findings suggest that HIV-associated brain injury leads to reduced efficiency in the normal attention network, thus requiring reorganization and increased usage of neural reserves to maintain performance during attention-requiring tasks. Exceeding the brain reserve capacity may lead to attention deficits and cognitive impairment in HIV patients.
Chang
Linda
L
Medical Department, Brookhaven National Laboratory, Upton, NY, USA. lchang@hawaii.edu
Tomasi
Dardo
D
Yakupov
Renat
R
Lozar
Carl
C
Arnold
Sheeba
S
Caparelli
Elisabeth
E
Ernst
Thomas
T
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001930:Brain Injuries / Q000503:physiopathology* / Q000821:virology; D001931:Brain Mapping; D018791:CD4 Lymphocyte Count / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006678:HIV; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000503:physiopathology* / Q000821:virology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D019562:Viral Load / Q000379:methods; D014796:Visual Perception / Q000502:physiology
D010100:Oxygen