Neural correlates of attention and working memory deficits in HIV patients.
OBJECTIVE
To evaluate the neural correlates of attention and working memory deficits in patients with HIV-1.


METHODS
fMRI was used to evaluate brain activity in 11 patients with HIV and 11 age-, sex-, education-, and handedness-matched seronegative subjects, while performing a battery of tasks that required different levels of attention for working memory.


RESULTS
Patients with HIV showed greater brain activation (blood oxygenation level dependent signal changes) in some regions compared with control subjects while performing the same tasks. For the simpler tasks, patients with HIV showed greater activation in the parietal regions. However, with more difficult tasks, patients with HIV showed greater activation additionally in the frontal lobes. Reaction times during these tasks were slower but accuracy was similar in the patients with HIV compared with control subjects.


CONCLUSIONS
Injury to the neural substrate caused by HIV infection may necessitate greater attentional modulation of the neural circuits, hence a greater use of the brain reserve; additional activation of the frontal lobes is required to perform the more complex tasks. The task-dependent increased frontal activation in patients with HIV suggests that the neural correlate of attentional deficits may be excessive attentional modulation as a result of frontostriatal brain injury.
Chang
L
L
Department of Neurology, UCLA School of Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA. ChangL@bnl.gov
Speck
O
O
Miller
E N
EN
Braun
J
J
Jovicich
J
J
Koch
C
C
Itti
L
L
Ernst
T
T
D015526:AIDS Dementia Complex / Q000503:physiopathology*; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D003342:Corpus Striatum / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D015497:HIV-1; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D011930:Reaction Time / Q000502:physiology