PROJECT SUMMARY/ABSTRACT
In the era of combination antiretroviral therapy (cART), the prevalence of HIV-associated neurocognitive
disorders, or HAND, remains high in people with HIV (PWH); as a result, there is increasing pressure to
identify neural targets for effective therapies. However, to develop effective HAND treatments, a strong need
exists for the development of sensitive behavioral tests that can quickly screen and effectively identify
probable neurocognitive impairment in PWH and biomarkers that can accurately determine HAND status and
evaluate therapeutic effects. This 5-year prospective, controlled, cross-sectional and longitudinal observational
study is theoretically driven and specifically designed to tackle these challenges.
Neural injury to the frontostriatal circuits (plus hippocampus, thalamus, and other associated regions) has
long been recognized as a key component in HAND; however, the association between frontostriatal injury and
HAND status remains to be elucidated. Recent findings suggest that injury to different key regions in the
frontostriatal circuits may play differential roles in HAND: frontal injury is more prevalent in PWH, but striatal
injury better predicts HAND status. This suggests that an accurate assessment of neural injury at different
frontostriatal regions (in addition to other key regions such as the hippocampus and thalamus) may
have the potential to serve as a biomarker to assist with HAND diagnosis and characterization. To test
this hypothesis, we will investigate frontostriatal injury in PWH using two behavioral paradigms that are known
to involve distinct frontostriatal regions, along with two advanced functional MRI (fMRI) techniques: fMRI-
adaptation (fMRI-A) and multivariate pattern analysis (MVPA). Compared to conventional fMRI techniques,
fMRI-A and MVPA techniques can better estimate neural tuning/selectivity that can be quantitatively related to
behavioral performance. Briefly, we hypothesize that frontostriatal injury – a central component in HAND – is
highly prevalent in PWH and can be assessed behaviorally via two behavioral paradigms (Aim 1a), and
neurally via fMRI-A & MVPA (Aim 1b). Neural injury to other regions/networks will be assessed using a
multimodal MRI approach (Aim 2). The integration of behavioral & fMRI data from Aim 1 with multimodal MRI
data from Aim 2 will help to assess the degree of neural injury at frontostriatal and other regions/networks,
which in turn may serve as a biomarker for HAND status (Aim 3). The probable impact of common
comorbidities will also be investigated.
In summary, this proposal is theoretically driven and highly innovative, with a strong promise for future clinically
relevant development. The feasibility of the proposed research is supported by a strong foundation in cognitive
neuroscience and neuroHIV, strong preliminary data, and an established research team. The success of this
proposed project may help to develop sensitive behavioral tests that can effectively detect mild neurocognitive
impairment in PWH, and a biomarker that can assist in determining HAND status/severity.