Human immunodeficiency virus‐related decreases in corpus callosal integrity and corresponding increases in functional connectivity

Abstract

People living with human immunodeficiency virus (PLWH) often have neurocognitive impairment. However, findings on HIV-related differences in brain network function underlying these impairments are inconsistent. One principle frequently absent from these reports is that brain function is largely emergent from brain structure. PLWH commonly have degraded white matter; we hypothesized that functional communities connected by degraded white matter tracts would show abnormal functional connectivity. We measured white matter integrity in 69 PLWH and 67 controls using fractional anisotropy (FA) in 24 intracerebral white matter tracts. Then, among tracts with degraded FA, we identified gray matter regions connected to these tracts and measured their functional connectivity during rest. Finally, we identified cognitive impairment related to these structural and functional connectivity systems. We found HIV-related decreased FA in the corpus callosum body (CCb), which coordinates activity between the left and right hemispheres, and corresponding increases in functional connectivity. Finally, we found that individuals with impaired cognitive functioning have lower CCb FA and higher CCb functional connectivity. This result clarifies the functional relevance of the corpus callosum in HIV and provides a framework in which abnormal brain function can be understood in the context of abnormal brain structure, which may both contribute to cognitive impairment.

Demographic and clinical characteristics, seizure disorders, and antiepileptic drug usage in different types of corpus callosum disorders: a comparative study in children

“…Existing research has also suggested a correlation between corpus callosum abnormalities and an increased predisposition to epilepsy and other neurological disorders [ 17 – 19 ]. The corpus callosum is well-recognized for its fundamental role in facilitating communication between both brain hemispheres, and any aberrations in its development can result in cognitive and developmental challenges [ 20 , 21 ].…”

Longitudinal white matter alterations in SIVmac239 infected rhesus monkeys with and without regular cART treatment

“…[59] The lack of aggressive HIV associated WM damage in the CC after cART suggested that early treatment is neuroprotective to the CC to some extent. [74] On one hand, cART may contribute to synaptic injury via oxidative stress as has been demonstrated in vitro and in animal models[75]. On the other hand, early and continuous antiretroviral therapy can be neuroprotective, limiting the damage to white matter.…”

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis

“…This CTG algorithm summarizes connectivity in canonical, well-characterized fiber systems. Streamline connectivity between regions of interest (ROIs) of a sub-parcellated version of the Harvard-Oxford Atlas ( Tzourio-Mazoyer et al, 2002 ), defined originally in MNI space, and used previously in our work ( Beynel et al, 2020 , Davis et al, 2017 ) and others ( Hall et al 2021 ). One disadvantage of this standard atlas is that the ROIs could have different sizes.…”