HIV infection and the fronto-striatal system: a systematic review and meta-analysis of fMRI studies

HIV-1 Tat protein alters medial prefrontal cortex neuronal activity and recognition memory

Despite advancements in combined antiretroviral therapy, human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) continue to affect 40%-50% of people living with HIV. While neuroimaging studies have revealed HIV-1-induced alterations in cortical networks and brain macrostructures, it still remains unclear how individual neurons in the medial prefrontal cortex (mPFC) are affected during recognition memory. Using in vivo calcium imaging in an HIV-1 transactivator of transcription (Tat) transgenic mouse model, we examined mPFC neuronal activity during a novel object recognition memory task. Our findings show that HIV Tat expression reduces overall neuronal activity in Tat(+) mice without altering the number of activated cells. Moreover, distinct neuronal subpopulations are up- and downmodulated in both Tat(-) and Tat(+) mice depending on object exploration. Importantly, familiarity-driven increases in mPFC activity were disrupted by HIV Tat expression. These findings enhance our understanding of HAND and may inform future pharmacological strategies aimed at restoring cognitive function.

Executive Functions are Independently Associated with Cognitive Dispersion in HIV Disease

OBJECTIVE

People with HIV (PWH) can demonstrate elevated cognitive intraindividual variability (IIV-dispersion) that is associated with everyday functioning problems. Higher IIV-dispersion is theorized to reflect lapses in executive aspects of cognitive control, but few studies have directly evaluated this possibility.

METHOD

72 PWH completed the Cogstate and clinical measures of executive functions, psychomotor speed, and episodic memory. IIV-dispersion was calculated with the coefficient of variation (CoV) from six age-adjusted Cogstate subtest scores.

RESULTS

Multiple regression showed that the three domain-level cognitive predictors explained 8% of the variance in Cogstate CoV (p = .03). Within this model, poorer executive functions were moderately associated with higher Cogstate CoV (p = .01), but the psychomotor and episodic memory domains were not (ps > .05).

CONCLUSIONS

Findings align with cognitive theory in demonstrating IIV-dispersion is uniquely associated with independent measures of executive functions among PWH. Future experimental and mechanistic studies are needed to determine the precise executive aspects of IIV-dispersion.

Medial prefrontal cortex connectivity with the nucleus accumbens is related to HIV serostatus, perceptions of psychological stress, and monocyte expression of TNF-a

Post-menopausal persons living with HIV (PWH) report elevated levels of psychological stress and monocyte activation compared to persons living without HIV (PWOH). Resting state functional connectivity (rsFC) of mesolimbic brain regions underpinning stress and emotion regulation are susceptible to inflammatory insult. Although psychological stress is elevated, rsFC reduced, and CD16+ monocytes overexpressed in the brains of PWH, it is unclear whether the relationships amongst these variables differ compared to PWOH. An ethnically diverse sample of postmenopausal women, 24 PWH and 30 PWOH provided self-report mood surveys and provided peripheral blood specimens to quantify LPS-stimulated CD16+/- expression of TNF-α via flow cytometric analysis. An anatomical and resting state functional MRI scan were used to derive time-series metrics of connectivity between the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAcc) as well as the amygdala. A positive association was observed between levels of perceived stress and CD16+/- TNF-α in both LPS-stimulated and unstimulated cells. PLWH showed lower connectivity between mPFC and NAcc. In turn, lower rsFC between these regions predicted greater psychological stress and proportion of CD16-, but not CD16+, cells expression of TNF-α. Neuroimmune effects of monocyte inflammation on the functional connectivity of mesolimbic regions critical for discrimination of uncertainty-safety and reward signals were observed in an ethnically diverse sample of postmenopausal women living with and without HIV. PWH showed lower mPFC-NAcc functional connectivity, which in turn was associated with greater perceived stress.

The Effect of Efavirenz on Reward Processing in Asymptomatic People Living with HIV: A Randomized Controlled Trial

Functional magnetic resonance imaging (fMRI) studies have demonstrated that HIV-infection affects the fronto-striatal network. It has not been examined what impact efavirenz (EFV), an antiretroviral drug notorious for its neurocognitive effects, has on the reward system: a key subcomponent involved in depressive and apathy symptoms. Therefore, this study aims to investigate the effect of EFV on reward processing using a monetary incentive delay (MID) task. In this multicenter randomized controlled trial, asymptomatic adult participants stable on emtricitabine/tenofovirdisoproxil fumarate (FTC/TDF)/EFV were randomly assigned in a 2:1 ratio to switch to FTC/TDF/rilpivirine (RPV) (n = 30) or continue taking FTC/TDF/EFV (n = 13). At baseline and 12 weeks after therapy switch, both groups performed an MID task. Behavior and functional brain activity related to reward anticipation and reward outcome were assessed with blood-oxygen-level-dependent fMRI. Both groups were matched for age, education level, and time since HIV diagnosis and on EFV. At the behavioral level, both groups had faster response times and better response accuracy during rewarding versus nonrewarding trials, with no improvement resulting from switching FTC/TDF/EFV to FTC/TDF/RPV. No significant change in activation related to reward anticipation in the ventral striatum was found after switching therapy. Both groups had significantly higher activation levels over time, consistent with a potential learning effect. Similar activity related to reward outcome in the orbitofrontal cortex was found. Discontinuing FTC/TDF/EFV was not found to improve activity related to reward anticipation in asymptomatic people living with HIV, with similar cortical functioning during reward outcome processing. It is therefore likely that EFV does not affect motivational control. Further research is needed to determine whether EFV affects motivational control in HIV populations with different characteristics.

Association between cannabis use disorder and greater apathy in adults with HIV

BACKGROUND

Apathy is prevalent among people with HIV (PWH) and is associated with poor clinical outcomes. Cannabis use and Cannabis Use Disorder (CUD) are also disproportionately prevalent among PWH. CUD and younger onset of cannabis use may be linked to apathy in the general population; however, patterns of use most strongly associated with apathy have not been firmly established, and it is unclear whether cannabis use is linked to apathy in PWH.

METHODS

We examined associations in 311 adult PWH between Apathy Evaluation Scale-Self (AES-S) scores and CUD history (current/past/no CUD/no cannabis use) and between AES-S scores and age of CUD onset (adolescent-onset/adult-onset). We also examined robustness of associations to adjustment for depressive symptoms (which may overlap with apathy symptoms) and alcohol use.

RESULTS

Current CUD was associated with greater AES-S scores relative to cannabis users with no CUD history (β = 2.13, 95 % CI = 0.37-3.90, p = 0.018). Adolescent-onset CUD was not associated with greater apathy relative to adult-onset CUD (β = 0.56, 95 % CI = -2.57 - 3.68, p = 0.7). Associations became nonsignificant after adjustment for depressive symptoms, but not after adjustment for alcohol use. Alcohol use was correlated with apathy (r = 0.19, 95 % CI: 0.076-0.29, p = 0.001).

CONCLUSIONS

Cannabis Use Disorder and at-risk alcohol use are associated with apathy among PWH; this finding highlights the need for substance use disorder prevention and treatment among PWH.

Bacterial, Viral, and Prion Infectious Diseases of the Brain

Diagnosis of brain infections is based on a combination of clinical features, laboratory markers, and imaging findings. Imaging characterizes the extent and severity of the disease, aids in guiding diagnostic and therapeutic procedures, monitors response to treatment, and demonstrates complications. This review highlights the characteristic imaging manifestations of bacterial and viral infections in the brain.

Underlying Neural Mechanisms of Cognitive Improvement in Fronto-striatal Response Inhibition in People Living with HIV Switching Off Efavirenz: A Randomized Controlled BOLD fMRI Trial

INTRODUCTION

It is unclear whether neurotoxicity due to the antiretroviral drug efavirenz (EFV) results in neurocognitive impairment in people living with HIV (PLWH). Previously, we found that discontinuing EFV was associated with improved processing speed and attention on neuropsychological assessment. In this imaging study, we investigate potential neural mechanisms underlying this cognitive improvement using a BOLD fMRI task assessing cortical and subcortical functioning.

METHODS

Asymptomatic adult PLWH stable on emtricitabine/tenofovirdisoproxil/efavirenz were randomly (1:2) assigned to continue their regimen (n = 12) or to switch to emtricitabine/tenofovirdisoproxil/rilpivirine (n = 28). At baseline and after 12 weeks, both groups performed the Stop-Signal Anticipation Task, which tests reactive and proactive inhibition (indicative of subcortical and cortical functioning, respectively), involving executive functioning, working memory, and attention. Behavior and BOLD fMRI activation levels related to processing speed and attention Z-scores were assessed in 17 pre-defined brain regions.

RESULTS

Both groups had comparable patient and clinical characteristics. Reactive inhibition behavioral responses improved for both groups on week 12, with other responses unchanged. Between-group activation did not differ significantly. For reactive inhibition, positive Pearson coefficients were observed for the change in BOLD fMRI activation levels and change in processing speed and attention Z-scores in all 17 regions in participants switched to emtricitabine/tenofovir disoproxil/rilpivirine, whereas in the control group, negative correlation coefficients were observed in 10/17 and 13/17 regions, respectively. No differential pattern was observed for proactive inhibition.

CONCLUSION

Potential neural mechanisms underlying cognitive improvement after discontinuing EFV in PLWH were found in subcortical functioning, with our findings suggesting that EFV's effect on attention and processing speed is, at least partially, mediated by reactive inhibition.

TRIAL REGISTRATION

Clinicaltrials.gov identifier [NCT02308332].

Apathy in persons living with HIV disease: A systematic narrative review

BACKGROUND

Apathy was identified as a feature of HIV early in the epidemic; however, there are no systematic reviews of the diverse literature on the sociodemographic and clinical correlates of apathy in HIV disease.

METHODS

The current study adopted a hybrid systematic-narrative review methodology in which we used PRISMA guidelines to identify, summarize, and critique peer-reviewed, empirical studies of apathy in HIV disease in the era of combination antiretroviral therapy.

RESULTS

A total of 34 studies of apathy in persons living with HIV (PLWH) were identified. Findings across these studies showed that apathy was reliably related to the structure of grey and white matter pathways commonly implicated in apathy, poorer everyday functioning, education, and other neuropsychiatric symptoms (e.g., depression). Apathy was not reliably associated with age, sex, race/ethnicity, cognition, and clinical markers of HIV disease.

LIMITATIONS

The current review does not provide rigorous quantitative estimates of clinical correlates of apathy, and the exclusion criteria of non-English and non-peer reviewed publications introduces risk of bias and Type I error.

CONCLUSIONS

Apathy occurs at higher rates in PLWH and is linked to neuroanatomical differences, as well as negative outcomes for everyday functions, aspects of neurocognition, and neuropsychiatric symptoms. As such, apathy is an important component to consider in the clinical assessment, diagnosis, and management of neurocognitive disorders in PLWH. Future work is needed to replicate existing findings with larger sample sizes and longitudinal designs, examine apathy as a multi-dimensional construct, and develop evidence-based treatments for apathy in PLWH.

Cognitive Intra-individual Variability in the Laboratory Is Associated With Greater Executive Dysfunction in the Daily Lives of Older Adults With HIV

BACKGROUND

Executive dysfunction, which is common among persons with HIV (PWH), can have an adverse impact on health behaviors and quality of life. Intra-individual variability (IIV) is a measure of within-person variability across cognitive tests that is higher in PWH and is thought to reflect cognitive dyscontrol.

OBJECTIVE

To assess whether cognitive IIV in the laboratory is associated with self-reported executive dysfunction in daily life among older PWH.

METHOD

Participants included 71 PWH aged ≥50 years who completed six subtests from the Cogstate battery and two subscales from the Frontal Systems Behavior Scale (FrSBe; self-report version). Cognitive IIV was calculated from the Cogstate as the coefficient of variation derived from age-adjusted normative T scores.

RESULTS

Cognitive IIV as measured by the Cogstate showed a significant, positive, medium-sized association with current FrSBe ratings of executive dysfunction but not disinhibition.

CONCLUSION

Higher cognitive IIV in the laboratory as measured by the Cogstate may be related to the expression of HIV-associated symptoms of executive dysfunction in daily life for older PWH.

Highly active antiretroviral therapy-related effects on morphological connectivity in HIV

OBJECTIVE

Suboptimal concentration of the antiretroviral drug is insufficient to inhibit HIV destruction on brain structure and function due to the resistance of blood brain barrier. We aimed to investigate highly active antiretroviral therapy (HAART)-related effects on the morphological connectivity in people with HIV (PWH).

DESIGN

Case-control study.

METHODS

Fifty-five HAART-treated for more than 3 months and 54 untreated PWH, as well as 66 demographically matched healthy controls underwent a high-resolution 3D T1-weighted MRI. Individual-level morphological brain network based on gray matter volume of 90 brain regions was constructed and network topological properties were analyzed. Network-based statistics (NBS) was performed to identify sub-networks showing significant differences in morphological connectivity. Correlation and mediation analyses were employed to evaluate associations between the morphological properties and clinical variables of PWH.

RESULTS

Although PWH exhibited small-world architecture in their morphological brain networks, untreated PWH demonstrated altered network properties while HAART-treated PWH showed relatively similar network properties compared to healthy controls. Furthermore, HAART-related effects were mainly involved the bilateral putamen and left thalamus. The findings of NBS further indicated the cortico-striatum-thalamic-cortical loop was involved in the therapeutic-associated morphological network. The positive correlations between the HAART treatment and nodal degree and efficiency of the putamen were mediated by the number of CD4 + T lymphocytes.

CONCLUSIONS

The topological properties are recovered to normal in PWH after HAART and the effects induced by HAART are mostly within the cortical-subcortical circuit.

Reversible large-scale network disruption correlates with neurocognitive improvement in HIV-associated minor neurocognitive disorder with combined anti-retroviral therapy intensification: a prospective longitudinal resting-state functional magnetic resonance imaging study

OBJECTIVE

HIV-associated neurocognitive disorder (HAND) affects multiple cognitive domains and currently, the neuropsychological testing is the gold standard to identify these deficits. The aim of this longitudinal 12-month pilot study is to determine the effect of intensified combination antiretroviral therapy (cART) on rs-fMRI in virally suppressed (both in CSF and blood) patients with active HAND (those who have progressive neurocognitive impairment) and correlated with neurocognitive function tests.

METHODS

In this pilot study, we have evaluated sixteen patients with active HAND with viral suppression in both blood and CSF to study the effect of cART on functional connectivity. Participants underwent rs-fMRI at the baseline (time point-1 (TP-1) and 12-month visits (time point-2 (TP-2)). Connectivity in the five major networks was measured at TP-1 and TP-2 using the seed-based approach. All the participants underwent a five-domain neuropsychological battery at TP-1 and TP-2. Neurocognitive scores (NC) as well as blood and CSF markers were correlated with functional connectivity (FC).

RESULTS

There was a significant increase in the FC between the two time points within the executive, salience, default mode, dorsal attention, and visual networks at voxel level threshold of p < 0.001 and cluster level threshold of p < 0.05 and corrected for false detection rate (FDR). The neurocognitive scores were positively correlated with all the networks at similar cluster and voxel level thresholds.

CONCLUSIONS

These results indicate that rs-fMRI can be potentially used as one of the biomarkers for treatment efficacy in HAND.

Resting state network connectivity alterations in HIV: Parallels with aging

The increasing incidence of age-related comorbidities in people with HIV (PWH) has led to accelerated aging theories. Functional neuroimaging research, including functional connectivity (FC) using resting-state functional magnetic resonance imaging (rs-fMRI), has identified neural aberrations related to HIV infection. Yet little is known about the relationship between aging and resting-state FC in PWH. This study included 86 virally suppressed PWH and 99 demographically matched controls spanning 22-72 years old who underwent rs-fMRI. The independent and interactive effects of HIV and aging on FC were investigated both within- and between-network using a 7-network atlas. The relationship between HIV-related cognitive deficits and FC was also examined. We also conducted network-based statistical analyses using a brain anatomical atlas (n = 512 regions) to ensure similar results across independent approaches. We found independent effects of age and HIV in between-network FC. The age-related increases in FC were widespread, while PWH displayed further increases above and beyond aging, particularly between-network FC of the default-mode and executive control networks. The results were overall similar using the regional approach. Since both HIV infection and aging are associated with independent increases in between-network FC, HIV infection may be associated with a reorganization of the major brain networks and their functional interactions in a manner similar to aging.

Alzheimer's Disease Pathology in Middle Aged and Older People with HIV: Comparisons with Non-HIV Controls on a Healthy Aging and Alzheimer's Disease Trajectory and Relationships with Cognitive Function

We determined the prevalence of Alzheimer's disease (AD) pathological hallmarks, amyloid-β and phosphorylated-Tau, in autopsied brains of 49 people with HIV (PWH) (ages: 50-68; mean age = 57.0) from the National NeuroAIDS Tissue Consortium and in a comparative cohort of 55 people without HIV (PWoH) from the UC San Diego Alzheimer's Disease Research Center (17 controls, 14 mild cognitive impairment, 24 AD; ages: 70-102, mean age = 88.7). We examined how AD pathology relates to domain-specific cognitive functions in PWH overall and in sex-stratified samples. Amyloid-β and phosphorylated-Tau positivity (presence of pathology of any type/density) was determined via immunohistochemistry in AD-sensitive brain regions. Among PWH, amyloid-β positivity ranged from 19% (hippocampus) to 41% (frontal neocortex), and phosphorylated-Tau positivity ranged from 47% (entorhinal cortex) to 73% (transentorhinal cortex). Generally, AD pathology was significantly less prevalent, and less severe when present, in PWH versus PWoH regardless of cognitive status. Among PWH, positivity for AD pathology related most consistently to memory-related domains. Positivity for p-Tau pathology related to memory-related domains in women with HIV only, although the sample size of women with HIV was small (n = 10). Results indicate that AD pathology is present in a sizable portion of middle aged and older PWH, although not to the extent in older PWoH. Studies with better age-matched PWoH are needed to examine the effect of HIV status on AD pathology.

Resting state connectivity in people living with HIV before and after stopping heavy drinking

Background

Heavy alcohol use in people living with HIV (PLWH) has widespread negative effects on neural functioning. It remains unclear whether experimentally-induced reduction in alcohol use could reverse these effects. We sought to determine the effects of 30-days drinking cessation/reduction on resting state functional connectivity in people with and without HIV.

Methods

Thirty-five participants (48.6% PLWH) demonstrating heavy alcohol use attempted to stop drinking for 30 days via contingency management (CM). MRI was acquired at baseline and after thirty days, and functional connectivity across five resting-state fMRI (rsfMRI) networks was calculated with the Conn toolbox for Matlab and examined in relation to transdermal alcohol concentration (TAC) recorded by the ankle-worn secure continuous remote alcohol monitor (SCRAM) and self-reported alcohol use (timeline follow-back; TLFB). Associations between alcohol use and reduction, HIV status, functional connectivity, and change in functional connectivity across five major rsfMRI networks were determined relative to the pre- and post-CM timepoints.

Results

Baseline resting-state functional connectivity was not significantly associated with average TAC-AUC during the pre-CM period, though higher self-reported alcohol use over the preceding 30 days was significantly associated with higher baseline connectivity within the Dorsal Attention Network (DAN; p-FDR < 0.05). Baseline connectivity within the Salience network was significantly negatively related to objective drinking reduction after intervention (DAN; p-FDR < 0.05), whereas baseline connectivity within the Limbic network was positively associated with self-reported drinking reduction (p-FDR < 0.05). Change in between-networks functional connectivity after intervention was significantly positively associated with biosensor-confirmed drinking reduction such that higher reduction was associated with stronger connectivity between the limbic and fronto-parietal control networks (p-FDR < 0.05). PLWH with lower DAN connectivity at baseline demonstrated poorer alcohol reduction than those with higher DAN connectivity at baseline.

Discussion

Lower resting-state functional connectivity of the Salience network significantly predicted stronger drinking reduction across all participants, suggesting a potential biomarker for reduced susceptibility to the environmental and social cues that often make alcohol use reduction attempts unsuccessful. Increased between-networks connectivity was observed in participants with higher alcohol reduction after CM, suggesting a positive benefit to brain connectivity associated with reduced drinking. PLWH with lower baseline DAN connectivity may not benefit as greatly from CM for alcohol reduction.

Cortico-striatal networking deficits associated with advanced HIV disease and cocaine use

Cocaine use is disproportionately prevalent in people with HIV (PWH) and is known to potentiate HIV neuropathogenesis. As both HIV and cocaine have well-documented cortico-striatal effects, PWH who use cocaine and have a history of immunosuppression may exhibit greater FC deficits compared to PWH without these conditions. However, research investigating the legacy effects of HIV immunosuppression (i.e., a history of AIDS) on cortico-striatal functional connectivity (FC) in adults with and without cocaine use is sparse. Resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessment data from 273 adults were analyzed to examine FC in relation to HIV disease: HIV-negative (n = 104), HIV-positive with nadir CD4 ≥ 200 (n = 96), HIV-positive with nadir CD4 < 200 (AIDS; n = 73), and cocaine use (83 COC and 190 NON). Using independent component analysis/dual regression, FC was assessed between the basal ganglia network (BGN) and five cortical networks: dorsal attention network (DAN), default mode network, left executive network, right executive network, and salience network. There were significant interaction effects such that AIDS-related BGN-DAN FC deficits emerged in COC but not in NON participants. Independent of HIV, cocaine effects emerged in FC between the BGN and executive networks. Disruption of BGN-DAN FC in AIDS/COC participants is consistent with cocaine potentiation of neuro-inflammation and may be indicative of legacy HIV immunosuppressive effects. The current study bolsters previous findings linking HIV and cocaine use with cortico-striatal networking deficits. Future research should consider the effects of the duration of HIV immunosuppression and early treatment initiation.

Relationship between reward-related evoked potentials and real-world motivation in older people living with human immunodeficiency virus

Apathy, a clinical disorder characterized by low motivation, is prevalent in people living with Human Immunodeficiency Virus (HIV). It affects mental and physical health-related quality-of-life, medication adherence, and is associated with cognitive decline. However, the causes of apathy and the underlying brain mechanisms in HIV are unknown. Brain responses to reward may be relevant to understanding apathy and might serve as biomarkers for diagnosis or treatment response. Electroencephalogram (EEG) responses to gain and loss feedback in simple guessing tasks have been related to apathy in neurodegenerative conditions and healthy individuals. The primary aim of this study is to contribute evidence regarding the relationship between two EEG correlates of reward processing, the Reward Positivity, and the Feedback-P300, and real-world motivated behavior indicated by self-reported hours engaged in goal-directed leisure activities per week, in older individuals with well-controlled HIV infection. High-density EEG was collected from 75 participants while they performed a guessing task with gain or loss feedback. We found that a later component of reward processing, the Feedback-P300, was related to real-world engagement, while the earlier Reward Positivity was not. The Feedback-P300 measured with EEG holds promise as a biomarker for motivated behavior in older people living with HIV. These findings lay the groundwork for a better understanding of the neurobiology of apathy in this condition.

Interactive Effects of HIV Infection and Cannabis Use on Insula Subregion Functional Connectivity

Chronic inflammation in the central nervous system is one mechanism through which human immunodeficiency virus (HIV) may lead to progressive cognitive decline. Given cannabis's (CB's) anti-inflammatory properties, use prevalence among people living with HIV (PLWH), and evidence implicating the insula in both, we examined independent and interactive effects of HIV and CB on insular circuitry, cognition, and immune function. We assessed resting-state functional connectivity (rsFC) of three insula subregions among 106 participants across four groups (co-occurring: HIV+/CB+; HIV-only: HIV+/CB-; CB-only: HIV-/CB+; controls: HIV-/CB-). Participants completed a neurocognitive battery assessing functioning across multiple domains and self-reported somatic complaints. Blood samples quantified immune function (T-cell counts) and inflammation (tumor necrosis factor alpha [TNF-α]). We observed interactive HIV × CB effects on rsFC strength between two anterior insula (aI) subregions and sensorimotor cortices such that, CB appeared to normalize altered rsFC among non-using PLWH. Specifically, compared to controls, HIV-only and CB-only groups displayed decreased dorsal anterior insula (DI) - postcentral gyrus rsFC and increased ventral anterior insula (VI) - supplementary motor area rsFC, whereas the co-occurring group displayed DI and VI rsFC more akin to that of controls. Altered DI - postcentral rsFC correlated with decreased processing speed and somatic complaints, but did not significantly correlate with inflammation (TNF-α). These outcomes implicate insula - sensorimotor neurocircuitries in HIV and CB and are consistent with prior work suggesting that CB use may normalize insula functioning among PLWH.

The association between benzodiazepine use and greater risk of neurocognitive impairment is moderated by medical burden in people with HIV

Benzodiazepine use is linked to neurocognitive impairment (NCI) in the general population and people with HIV (PWH); however, this relationship may depend on age-related factors such as medical comorbidities, which occur at an elevated rate and manifest earlier in PWH. We retrospectively examined whether chronological age or medical burden, a clinical marker for aging, moderated the relationship between benzodiazepine use and NCI in PWH. Participants were 435 PWH on antiretroviral therapy who underwent neurocognitive and medical evaluations, including self-reported current benzodiazepine use. A medical burden index score (proportion of accumulated multisystem deficits) was calculated from 28 medical deficits. Demographically corrected cognitive deficit scores from 15 neuropsychological tests were used to calculate global and domain-specific NCI based on established cut-offs. Logistic regressions separately modeled global and domain-specific NCI as a function of benzodiazepine x age and benzodiazepine x medical burden interactions, adjusting for current affective symptoms and HIV disease characteristics. A statistically significant benzodiazepine x medical burden interaction (p = .006) revealed that current benzodiazepine use increased odds of global NCI only among those who had a high medical burden (index score > 0.3 as indicated by the Johnson–Neyman analysis), which was driven by the domains of processing speed, motor, and verbal fluency. No age x benzodiazepine interactive effects on NCI were present. Findings suggest that the relationship between BZD use and NCI among PWH is specific to those with greater medical burden, which may be a greater risk factor for BZD-related NCI than chronological age.

Escalated (Dependent) Oxycodone Self-Administration Is Associated with Cognitive Impairment and Transcriptional Evidence of Neurodegeneration in Human Immunodeficiency Virus (HIV) Transgenic Rats

Substance use disorder is associated with accelerated disease progression in people with human immunodeficiency virus (HIV; PWH). Problem opioid use, including high-dose opioid therapy, prescription drug misuse, and opioid abuse, is high and increasing in the PWH population. Oxycodone is a broadly prescribed opioid in both the general population and PWH. Here, we allowed HIV transgenic (Tg) rats and wildtype (WT) littermates to intravenously self-administer oxycodone under short-access (ShA) conditions, which led to moderate, stable, "recreational"-like levels of drug intake, or under long-access (LgA) conditions, which led to escalated (dependent) drug intake. HIV Tg rats with histories of oxycodone self-administration under LgA conditions exhibited significant impairment in memory performance in the novel object recognition (NOR) paradigm. RNA-sequencing expression profiling of the medial prefrontal cortex (mPFC) in HIV Tg rats that self-administered oxycodone under ShA conditions exhibited greater transcriptional evidence of inflammation than WT rats that self-administered oxycodone under the same conditions. HIV Tg rats that self-administered oxycodone under LgA conditions exhibited transcriptional evidence of an increase in neuronal injury and neurodegeneration compared with WT rats under the same conditions. Gene expression analysis indicated that glucocorticoid-dependent adaptations contributed to the gene expression effects of oxycodone self-administration. Overall, the present results indicate that a history of opioid intake promotes neuroinflammation and glucocorticoid dysregulation, and excessive opioid intake is associated with neurotoxicity and cognitive impairment in HIV Tg rats.

Neurofunctional characteristics of executive control in older people with HIV infection: a comparison with Parkinson's disease

Expression of executive dysfunctions is marked by substantial heterogeneity in people living with HIV infection (PLWH) and attributed to neuropathological degradation of frontostriatal circuitry with age and disease. We compared the neurophysiology of executive function in older PLWH and Parkinson's disease (PD), both affecting frontostriatal systems. Thirty-one older PLWH, 35 individuals with PD, and 28 older healthy controls underwent executive task-activated fMRI, neuropsychological testing, and a clinical motor exam. fMRI task conditions distinguished cognitive control operations, invoking a lateral frontoparietal network, and motor control operations, activating a cerebellar-precentral-medial prefrontal network. HIV-specific findings denoted a prominent sensorimotor hypoactivation during cognitive control and striatal hypoactivation during motor control related to CD4⁺ T cell count and HIV disease duration. Activation deficits overlapped for PLWH and PD, relative to controls, in dorsolateral frontal, medial frontal, and middle cingulate cortices for cognitive control, and in limbic, frontal, parietal, and cerebellar regions for motor control. Thus, despite well-controlled HIV infection, frontostriatal and sensorimotor activation deficits occurred during executive control in older PLWH. Overlapping activation deficits in posterior cingulate and hippocampal regions point toward similarities in mesocorticolimbic system aberrations among older PLWH and PD. The extent of pathophysiology in PLWH was associated with variations in immune system health, neural signature consistent with subclinical parkinsonism, and mild neurocognitive impairment. The failure to adequately engage these pathways could be an early sign for cognitive and motor functional decline in the aging population of PLWH.

HIV infection is linked with reduced error-related default mode network suppression and poorer medication management abilities

OBJECTIVE

Brain activity linked with error processing has rarely been examined among persons living with HIV (PLWH) despite importance for monitoring and modifying behaviors that could lead to adverse health outcomes (e.g., medication non-adherence, drug use, risky sexual practices). Given that cannabis (CB) use is prevalent among PLWH and impacts error processing, we assessed the influence of HIV serostatus and chronic CB use on error-related brain activity while also considering associated implications for everyday functioning and clinically-relevant disease management behaviors.

METHODS

A sample of 109 participants, stratified into four groups by HIV and CB (HIV+/CB+, n = 32; HIV+/CB-, n = 27; HIV-/CB+, n = 28; HIV-/CB-, n = 22), underwent fMRI scanning while completing a modified Go/NoGo paradigm called the Error Awareness Task (EAT). Participants also completed a battery of well-validated instruments including a subjective report of everyday cognitive failures and an objective measure of medication management abilities.

RESULTS

Across all participants, we observed expected error-related anterior insula (aI) activation which correlated with better task performance (i.e., less errors) and, among HIV- participants, fewer self-reported cognitive failures. Regarding awareness, greater insula activation as well as greater posterior cingulate cortex (PCC) deactivation were notably linked with aware (vs. unaware) errors. Regarding group effects, unlike HIV- participants, PLWH displayed a lack of error-related deactivation in two default mode network (DMN) regions (i.e., PCC, medial prefrontal cortex [mPFC]). No CB main or interaction effects were detected. Across all participants, reduced error-related PCC deactivation correlated with reduced medication management abilities and PCC deactivation mediated the effect of HIV on such abilities. More lifetime CB use was linked with reduced error-related mPFC deactivation among HIV- participants and poorer medication management across CB users.

CONCLUSIONS

These results demonstrate that insufficient error-related DMN suppression linked with HIV infection, as well as chronic CB use among HIV- participants, has real-world consequences for medication management behaviors. We speculate that insufficient DMN suppression may reflect an inability to disengage task irrelevant mental operations, ultimately hindering error monitoring and behavior modification.

Executive functions mediate the association between alcohol use and declarative memory symptoms in daily life

Alcohol use is associated with memory problems in young adults with HIV, but the cognitive mechanisms of that association are not known. Sixty adults (aged 19-24 years) living with HIV were administered the Alcohol, Smoking, and Substance Involvement Screening Test to assess alcohol use, Behavior Rating Inventory of Executive Function for self-reported executive functions, and the Prospective and Retrospective Memory Questionnaire (PRMQ) for dailiy memory functioning. Controlling for mood, self-reported executive functions fully mediated the relationship between alcohol use and memory (indirect effect b=.568, 95%CI [.209,.888]). Findings suggest that self-reported executive dysregulation of memory processes (e.g., Strategic encoding and retrieval) may drive the effects of alcohol use on daily memory symptoms.

Modeling the Effects of HIV and Aging on Resting-State Networks Using Machine Learning

BACKGROUND

The relationship between HIV infection, the functional organization of the brain, cognitive impairment, and aging remains poorly understood. Understanding disease progression over the life span is vital for the care of people living with HIV (PLWH).

SETTING

Virologically suppressed PLWH (n = 297) on combination antiretroviral therapy and 1509 HIV-uninfected healthy controls were evaluated. PLWH were further classified as cognitively normal (CN) or cognitively impaired (CI) based on neuropsychological testing.

METHODS

Feature selection identified resting-state networks (RSNs) that predicted HIV status and cognitive status within specific age bins (younger than 35 years, 35-55 years, and older than 55 years). Deep learning models generated voxelwise maps of RSNs to identify regional differences.

RESULTS

Salience (SAL) and parietal memory networks (PMNs) differentiated individuals by HIV status. When comparing controls with PLWH CN, the PMN and SAL had the strongest predictive strength across all ages. When comparing controls with PLWH CI, the SAL, PMN, and frontal parietal network (FPN) were the best predictors. When comparing PLWH CN with PLWH CI, the SAL, FPN, basal ganglia, and ventral attention were the strongest predictors. Only minor variability in predictive strength was observed with aging. Anatomically, differences in RSN topology occurred primarily in the dorsal and rostral lateral prefrontal cortex, cingulate, and caudate.

CONCLUSION

Machine learning identified RSNs that classified individuals by HIV status and cognitive status. The PMN and SAL were sensitive for discriminating HIV status, with involvement of FPN occurring with cognitive impairment. Minor differences in RSN predictive strength were observed by age. These results suggest that specific RSNs are affected by HIV, aging, and HIV-associated cognitive impairment.

Preliminary In Vivo Evidence of Reduced Synaptic Density in Human Immunodeficiency Virus (HIV) Despite Antiretroviral Therapy

BACKGROUND

Synaptic injury is a pathological hallmark of neurological impairment in people living with human immunodeficiency virus (HIV, PLWH), a common complication despite viral suppression with antiretroviral therapy (ART). Measurement of synaptic density in living humans may allow better understanding of HIV neuropathogenesis and provide a dynamic biomarker for therapeutic studies. We applied novel synaptic vesical protein 2A (SV2A) positron emission tomographic (PET) imaging to investigate synaptic density in the frontostriatalthalamic region in PLWH and HIV-uninfected participants.

METHODS

In this cross-sectional pilot study,13 older male PLWH on ART underwent magnetic resonance imaging (MRI) and PET scanning with the SV2A ligand [11C]UCB-J with partial volume correction and had neurocognitive assessments. SV2A binding potential (BPND) in the frontostriatalthalamic circuit was compared to 13 age-matched HIV-uninfected participants and assessed with respect to neurocognitive performance in PLWH.

RESULTS

PLWH had 14% lower frontostriatalthalamic SV2A synaptic density compared to HIV-uninfected (PLWH: mean [SD], 3.93 [0.80]; HIV-uninfected: 4.59 [0.43]; P = .02, effect size 1.02). Differences were observed in widespread additional regions in exploratory analyses. Higher frontostriatalthalamic SV2A BPND associated with better grooved pegboard performance, a measure of motor coordination, in PLWH (r = 0.61, P = .03).

CONCLUSIONS

In a pilot study, SV2A PET imaging reveals reduced synaptic density in older male PLWH on ART compared to HIV-uninfected in the frontostriatalthalamic circuit and other cortical areas. Larger studies controlling for factors in addition to age are needed to determine whether differences are attributable to HIV or comorbidities in PLWH. SV2A imaging is a promising biomarker for studies of neuropathogenesis and therapeutic interventions in HIV.

Neuropsychological and Psychosocial Functioning of Children with Perinatal HIV-Infection in The Netherlands

Advances in antiretroviral treatment improved the life expectancy of perinatally HIV-infected children. However, growing up with HIV provides challenges in daily functioning. This cross-sectional cohort study investigated the neuropsychological and psychosocial functioning of a group of perinatally HIV-infected children in the Netherlands and compared their outcomes with Dutch normative data and outcomes of a control group of uninfected siblings. The children’s functioning was assessed with internationally well-known and standardized questionnaires, using a multi-informant approach, including the perspectives of caregivers, teachers, and school-aged children. In addition, we explored the associations of socio-demographic and medical characteristics of the HIV-infected children with their neuropsychological and psychosocial functioning. Caregivers reported compromised functioning when compared to Dutch normative data for HIV-infected children in the areas of attention, sensory processing, social-emotional functioning, and health-related quality of life. Teachers reported in addition compromised executive functioning for HIV-infected children. A comparison with siblings revealed differences in executive functioning, problems with peers, and general health. The concurrent resemblance between HIV-infected children and siblings regarding problems in other domains implies that social and contextual factors may be of influence. A family-focused approach with special attention to the child’s socio-environmental context and additional attention for siblings is recommended.

Neurologic Complications of Human Immunodeficiency Virus

PURPOSE OF REVIEW

This article reviews the neurologic complications associated with human immunodeficiency virus (HIV) infection.

RECENT FINDINGS

Neurologic complications of HIV may be caused by direct virally mediated pathology, immune-mediated phenomena in response to viral infection, or opportunistic infections secondary to depletion of lymphocytes. These neurologic disorders may be influenced by the degree of immunosuppression (ie, CD4+ T-cell lymphocyte count) and stage of infection (early versus late), as well as use of antiretroviral therapy, and may manifest as a variety of central and peripheral neurologic syndromes, including the more commonly encountered HIV-associated cognitive disorders and length-dependent sensorimotor polyneuropathy, respectively. Immune dysregulation underlies the majority of these neurologic phenomena, as well as other HIV-associated conditions including immune reconstitution inflammatory syndrome (IRIS), CD8 lymphocytosis, and potentially the development of compartmentalized infection within the CSF, also referred to as CSF escape.

SUMMARY

This article reviews a spectrum of clinical syndromes and related neuropathologic states associated with HIV infection.

Gray matter volumes discriminate cognitively impaired and unimpaired people with HIV

BACKGROUND

Current diagnostic criteria of HIV-associated neurocognitive disorders (HAND) rely on neuropsychological assessments. The aim of this study was to evaluate if gray matter volumes (GMV) can distinguish people with HAND, neurocognitively unimpaired people with HIV (unimpaired PWH), and uninfected controls using linear discriminant analyses.

METHODS

A total of 231 participants, including 110 PWH and 121 uninfected controls, completed a neuropsychological assessment and an MRI protocol. Among PWH, HAND (n = 48) and unimpaired PWH (n = 62) designations were determined using the widely accepted Frascati criteria. We then assessed the extent to which GMV, corrected for intracranial volume, could accurately distinguish the three groups using linear discriminant analysis. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, area under the curve (AUC), and accuracy were computed for each model using the classification results based on GMV compared to the neuropsychological assessment.

RESULTS

The best performing model was comprised of bilaterally combined GMV and was stratified by sex. Among males, sensitivity was 85.2% (95% CI: 66.3%-95.8%), specificity was 97.0% (95% CI: 91.6%-99.4%), and the AUC was 0.91 (95% CI: 0.83-0.99). Among females, sensitivity was 100.0% (95% CI: 83.9%-100.0%), specificity was 98.8% (95% CI: 93.4%-100.0%), and the AUC was 0.99 (95% CI: 0.98-1.00).

CONCLUSIONS

GMV accurately discriminated HAND from unimpaired PWH and controls. Measures of GMV may be highly sensitive to HAND, and revisions to the Frascati criteria should consider including GMV in conjunction with a neuropsychological assessment to diagnose HAND.

Multimodal neuroimaging markers of variation in cognitive ability in older HIV+ men

OBJECTIVE

This study used converging methods to examine the neural substrates of cognitive ability in middle-aged and older men with well-controlled HIV infection.

METHODS

Seventy-six HIV+ men on antiretroviral treatment completed an auditory oddball task and an inhibitory control (Simon) task while time-locked high-density EEG was acquired; 66 had usable EEG data from one or both tasks; structural MRI was available for 43. We investigated relationships between task-evoked EEG responses, cognitive ability and immunocompromise. We also explored the structural correlates of these EEG markers in the sub-sample with complete EEG and MRI data (N = 27).

RESULTS

EEG activity was associated with cognitive ability at later (P300) but not earlier stages of both tasks. Only the oddball task P300 was reliably associated with HIV severity (nadir CD4). Source localization confirmed that the tasks engaged partially distinct circuits. Thalamus volume correlated with oddball task P300 amplitude, while globus pallidus volume was related to the P300 in both tasks.

INTERPRETATION

This is the first study to use task-evoked EEG to identify neural correlates of individual differences in cognition in men living with well-controlled HIV infection, and to explore the structural basis of the EEG markers. We found that EEG responses evoked by the oddball task are more reliably related to cognitive performance than those evoked by the Simon task. We also provide preliminary evidence for a subcortical contribution to the effects of HIV infection severity on P300 amplitudes. These results suggest brain mechanisms and candidate biomarkers for individual differences in cognition in HIV.

Verbal Learning Mediates the Relationship Between Executive Functions and a Laboratory Task of Medication Management in HIV Disease

OBJECTIVE

Impairments in executive functions and learning are common in HIV disease and increase the risk of nonadherence to antiretroviral therapy. The mixed encoding/retrieval profile of HIV-associated deficits in learning and memory is largely driven by dysregulation of prefrontal systems and related executive dysfunction. This study tested the hypothesis that learning may be one pathway by which executive dysfunction disrupts medication management in people living with HIV (PLWH).

METHOD

A total of 195 PLWH completed a performance-based laboratory task of medication management capacity and clinical measures of executive functions, verbal learning and memory, and motor skills.

RESULTS

Executive functions were significantly associated with verbal learning and medication management performance. In a model controlling for education, learning significantly mediated the relationship between executive functions and medication management, and this mediation was associated with a small effect size. In particular, executive dysfunction was associated with diminished use of higher-order learning strategies. Alternate models showed that executive functions did not mediate the relationship between learning and medication management nor did motor skills mediate the relationship between executive functions and medication management.

CONCLUSIONS

PLWH with executive dysfunction may demonstrate difficulty in learning new information, potentially due to ineffective strategy use, which may in turn put them at a higher risk for problems managing their medications in the laboratory. Future studies may wish to investigate whether compensatory neurocognitive training (e.g., using more effective learning strategies) may improve medication management among PLWH.

Future and past autobiographical memory in persons with HIV disease

Objective: While HIV disease is associated with impairment in declarative memory, the ability of people with HIV (PWH) to describe past and future autobiographical events is not known. Method: Participants included 63 PWH and 28 seronegative individuals ages 50-78 who completed standardized neurocognitive and everyday functioning assessments. Participants described four events from the recent past and four imagined events in the near future, details from which were classified as internal or external to the main event. Result: PWH produced fewer autobiographical details with small-to-medium effect sizes but did not differ from seronegative participants in meta-cognitive ratings of their performance. Performance of the study groups did not vary across past or future probes or internal versus external details; however, within the entire sample, past events were described in greater detail than future events, and more external than internal details were produced. Within the PWH group, the production of fewer internal details for future events was moderately associated with poorer prospective memory, executive dysfunction, and errors on a laboratory-based task of medication management. Conclusion: Older PWH may experience difficulty generating autobiographical details from the past and simulated events in the future, which may be related to executive dyscontrol of memory processes. Future studies might examine the role of future thinking in health behaviors such as medication adherence and retention in healthcare among PWH. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Depressive Symptoms Differentially Predict Neurocognition in Latinx and Non-Hispanic White People Living with HIV

OBJECTIVES

Depression is common in people living with HIV (PLWH) and can contribute to neurocognitive dysfunction. Depressive symptoms in PLWH are often measured by assessing only cognitive/affective symptoms. Latinx adults, however, often express depressive symptoms in a somatic/functional manner, which is not typically captured in assessments of depression among PLWH. Given the disproportionate burden of HIV that Latinx adults face, examining whether variations in expressed depressive symptoms differentially predict neurocognitive outcomes between Latinx and non-Hispanic white PLWH is essential.

METHODS

This cross-sectional study included 140 PLWH (71% Latinx; 72% male; mean (M) age = 47.1 ± 8.5 years; M education = 12.6 ± 2.9 years) who completed a comprehensive neurocognitive battery, Wechsler Test of Adult Reading (WTAR), and Beck Depression Inventory-II (BDI-II). Neurocognitive performance was measured using demographically adjusted T-scores. BDI-II domain scores were computed for the Fast-Screen (cognitive/affective items) score (BDI-FS) and non-FS score (BDI-NFS; somatic/functional items).

RESULTS

Linear regressions revealed that the BDI-NFS significantly predicted global neurocognitive function and processing speed in the Latinx group (p < .05), such that higher physical/functional symptoms predicted worse performance. In the non-Hispanic white group, the cognitive/affective symptoms significantly predicted processing speed (p = .02), with more symptoms predicting better performance. Interaction terms of ethnicity and each BDI sub-score indicated that Latinx participants with higher cognitive/affective symptoms performed worse on executive functioning.

CONCLUSIONS

Depressive symptoms differentially predict neurocognitive performance in Latinx and non-Hispanic white PLWH. These differences should be considered when conducting research and intervention among the increasingly culturally and ethnically diverse population of PLWH.

Assessment of executive functions as a measure of impairments in everyday functioning in persons with HIV

Persons with HIV can often present cognitive disorders such as those related to executive functioning, which could affect the daily life activities. The present study was designed to explore the predictive relationship between executive functions according to Miyake's model and the basic and instrumental skills of everyday functioning in a group of persons with HIV (PWH). Participants were recruited from outpatient treatment Hospital and assessed using a neuropsychological battery, a modified version of the Lawton and Brody basic and instrumental activities of daily life (ADL) scale and the Hospital Anxiety and Depression Scale (HADS). The results showed a low score in the executive function and significant relationship between executive functioning and the instrumental skills of the patients, with set-shifting being one of the most powerful predictors. The processes of executive functioning, particularly set-shifting, are related to the level of functioning in the skills required for independent living in the community, but not the skills of independent living in the home. This study seems to suggest the utility of assessing executive functions as a preventive measure for the development of dependencies in normal daily instrumental skills and as the focus of interdisciplinary interventions.

Neuroimaging and Cognitive Evidence for Combined HIV-Alcohol Effects on the Central Nervous System: A Review

Alcohol use disorder (AUD) among people living with HIV (PLWH) is a significant public health concern. Despite the advent of effective antiretroviral therapy, up to 50% of PLWH still experience worsened neurocognition, which comorbid AUD exacerbates. We report converging lines of neuroimaging and neuropsychological evidence linking comorbid HIV/AUD to dysfunction in brain regions linked to executive function, learning and memory, processing speed, and motor control, and consequently to impairment in daily life. The brain shrinkage, functional network alterations, and brain metabolite disruption seen in individuals with HIV/AUD have been attributed to several interacting pathways: viral proteins and EtOH are directly neurotoxic and exacerbate each other's neurotoxic effects; EtOH reduces antiretroviral adherence and increases viral replication; AUD and HIV both increase gut microbial translocation, promoting systemic inflammation and HIV transport into the brain by immune cells; and HIV may compound alcohol's damaging effects on the liver, further increasing inflammation. We additionally review the neurocognitive effects of aging, Hepatitis C coinfection, obesity, and cardiovascular disease, tobacco use, and nutritional deficiencies, all of which have been shown to compound cognitive changes in HIV, AUD, and in their comorbidity. Finally, we examine emerging questions in HIV/AUD research, including genetic and cognitive protective factors, the role of binge drinking in HIV/AUD-linked cognitive decline, and whether neurocognitive and brain functions normalize after drinking cessation.

Synergistic effects of HIV and marijuana use on functional brain network organization

HIV is associated with disruptions in cognition and brain function. Marijuana use is highly prevalent in HIV but its effects on resting brain function in HIV are unknown. Brain function can be characterized by brain activity that is correlated between regions over time, called functional connectivity. Neuropsychiatric disorders are increasingly being characterized by disruptions in such connectivity. We examined the synergistic effects of HIV and marijuana use on functional whole-brain network organization during resting state. Our sample included 78 adults who differed on HIV and marijuana status (19 with co-occurring HIV and marijuana use, 20 HIV-only, 17 marijuana-only, and 22 controls). We examined differences in local and long-range brain network organization using eight graph theoretical metrics: transitivity, local efficiency, within-module degree, modularity, global efficiency, strength, betweenness, and participation coefficient. Local and long-range connectivity were similar between the co-occurring HIV and marijuana use and control groups. In contrast, the HIV-only and marijuana-only groups were both associated with disruptions in brain network organization. These results suggest that marijuana use in HIV may normalize disruptions in brain network organization observed in persons with HIV. However, future work is needed to determine whether this normalization is suggestive of a beneficial or detrimental effect of marijuana on cognitive functioning in HIV.

Altered Gray Matter Volume and Functional Connectivity in Human Immunodeficiency Virus-Infected Adults

People living with human immunodeficiency virus (HIV) (PLWH) are at high risk of neurocognitive impairment. The pathogenesis of neurocognitive impairment remains unclear, and there is still no diagnostic biomarker. By coupling three-dimensional T1-weighted imaging and resting-state functional imaging, we explored structural and functional alterations in PLWH and examined whether such imaging alterations had the potential to denote neurocognitive function. A total of 98 PLWH and 47 seronegative controls aged 20-53 years were recruited. Structural alterations were first explored between HIV-negative controls and PLWH. Subsequently, brain regions showing gray matter alterations were used as seeds for separate whole-brain functional connectivity (FC) analysis. Finally, the relationships between imaging alterations and cognitive function were explored. PLWH suffered from thalamus, occipital lobe, and hippocampus/parahippocampus atrophy. Visual cortices in PLWH showed decreased anticorrelation with the posterior cingulate cortex and left angular gyrus of the default mode network. FC within the visual cortices (between the left calcarine and right calcarine) and in the thalamic prefrontal circuit and between the thalamus and somatosensory association cortex were also altered. In addition, FC between the left thalamus and right dorsolateral prefrontal cortex in the cognitively impaired group was significantly different from that in the cognitively normal group in PLWH. Partial correlation analysis uncorrected for multiple comparisons suggested that some imaging alterations can be associated with neurocognition. Our study supports the presence of brain atrophy and functional reconfiguration in PLWH. Imaging alterations can be associated with neurocognitive function. We hold that neuroimaging is a promising approach in evaluating PLWH and might have the potential to clarify the pathogenesis of HIV-associated neurocognitive disorder.

Lower CSF homovanillic acid relates to higher burden of neuroinflammation and depression in people with HIV disease

BACKGROUND

HIV-related neuroinflammation has been proposed as a catalyst for dopaminergic dysregulation in mesocortical pathways, which may contribute to the pathogenesis of depression. Abnormalities in dopaminergic neurotransmission and depression are common in people with HIV (PWH), however the link between dopamine (DA) and depression in PWH is poorly characterized. This study investigated CSF dopaminergic biomarkers, specifically DA and its metabolite, homovanillic acid (HVA), and examined their relationship with depressive symptoms and CSF neuroinflammatory markers in PWH and HIV-seronegative (HIV-) individuals.

METHODS

Participants were 102 HIV- individuals and 123 PWH (mean age = 42) who underwent neuropsychiatric evaluations and lumbar puncture. Current depression severity was classified using the Beck Depression Inventory-II (BDI-II). CSF was assayed for DA and HVA using high performance liquid chromatography and neuroinflammatory markers using immunoassays. Linear regressions modelled BDI-II scores as a function of HIV, dopaminergic biomarker z-scores, and their interaction, controlling for psychosocial factors. Correlational analyses examined dopaminergic and neuroinflammatory relationships.

RESULTS

PWH had significantly higher BDI-II scores than HIV- participants. DA and HVA were not associated with HIV status but both significantly moderated the effect of HIV on BDI-II scores, such that PWH exhibited higher depressive symptoms than HIV- participants only at lower concentrations of HVA (z ≤ 0.06) and DA (z ≤ 0.11). In PWH only, lower HVA significantly correlated with higher BDI-II scores and higher neuroinflammation, including higher MCP-1 and IP-10.

CONCLUSIONS

Results suggest that the pathophysiology of depression in PWH differs from that in HIV- individuals. Specifically, lower central dopaminergic activity was selectively associated with greater depressive symptoms and neuroinflammation in PWH. With the rise in consideration of DA agonists for the treatment of depression, these results suggest that PWH may show a greater response to these agents than their HIV- peers.

Independent and Combined Effects of Nicotine or Chronic Tobacco Smoking and HIV on the Brain: A Review of Preclinical and Clinical Studies

Tobacco smoking is highly prevalent among HIV-infected individuals. Chronic smokers with HIV showed greater cognitive deficits and impulsivity, and had more psychopathological symptoms and greater neuroinflammation than HIV non-smokers or smokers without HIV infection. However, preclinical studies that evaluated the combined effects of HIV-infection and tobacco smoking are scare. The preclinical models typically used cell cultures or animal models that involved specific HIV viral proteins or the administration of nicotine to rodents. These preclinical models consistently demonstrated that nicotine had neuroprotective and anti-inflammatory effects, leading to cognitive enhancement. Although the major addictive ingredient in tobacco smoking is nicotine, chronic smoking does not lead to improved cognitive function in humans. Therefore, preclinical studies designed to unravel the interactive effects of chronic tobacco smoking and HIV infection are needed. In this review, we summarized the preclinical studies that demonstrated the neuroprotective effects of nicotine, the neurotoxic effects of the HIV viral proteins, and the scant literature on nicotine or tobacco smoke in HIV transgenic rat models. We also reviewed the clinical studies that evaluated the neurotoxic effects of tobacco smoking, HIV infection and their combined effects on the brain, including studies that evaluated the cognitive and behavioral assessments, as well as neuroimaging measures. Lastly, we compared the different approaches between preclinical and clinical studies, identified some gaps and proposed some future directions. Graphical abstract Independent and combined effects of HIV and tobacco/nicotine. Left top and bottom panels: Both clinical studies of HIV infected persons and preclinical studies using viral proteins in vitro or in vivo in animal models showed that HIV infection could lead to neurotoxicity and neuroinflammation. Right top and bottom panels: While clinical studies of tobacco smoking consistently showed deleterious effects of smoking, clinical and preclinical studies that used nicotine show mild cognitive enhancement, neuroprotective and possibly anti-inflammatory effects. In the developing brain, however, nicotine is neurotoxic. Middle overlapping panels: Clinical studies of persons with HIV who were smokers typically showed additive deleterious effects of HIV and tobacco smoking. However, in the preclinical studies, when nicotine was administered to the HIV-1 Tg rats, the neurotoxic effects of HIV were attenuated, but tobacco smoke worsened the inflammatory cascade.

Impact of Cannabis Use on Brain Structure and Function in Suppressed HIV Infection

BACKGROUND

Brain atrophy and cognitive deficits persist among individuals with suppressed HIV disease. The impact of cannabis use is unknown.

METHODS

HIV+ and HIV- participants underwent cross-sectional magnetic resonance imaging and neuropsychological testing. Lifetime frequency, duration (years), and recency of cannabis use were self-reported. Relationships of cannabis use to resting-state functional connectivity (RSFC) and to 9 regional brain volumes were assessed with corrections for multiple comparisons. Peripheral blood cytokines and monocyte subsets were measured in the HIV+ group and examined in relation to cannabis exposure.

RESULTS

We evaluated 52 HIV+ [50.8 ± 7.1 years old; 100% on antiretroviral therapy ≥ 3 months; 83% with plasma viral load < 50 copies/mL] and 55 HIV- [54.0 ± 7.5 years old] individuals. Among HIV+ participants, recent cannabis use (within 12 months) was associated with diminished RSFC, including of occipital cortex, controlling for age. Duration of use correlated negatively with volumes of all regions (most strikingly the nucleus accumbens) independently of recent use and intracranial volume. Recent use was associated with larger caudate and white matter volumes and lower soluble vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1 concentrations. Duration of use correlated positively with psychomotor speed. Use > 10 times/lifetime was linked to more somatic symptoms, better executive function, and lower CD14⁺CD16⁺⁺ monocyte count.

CONCLUSION

HIV+ individuals demonstrated opposing associations with cannabis. Recent use may weaken RSFC and prolonged consumption may exacerbate atrophy of the accumbens and other brain regions. More frequent or recent cannabis use may reduce the inflammation and CD14⁺CD16⁺⁺ monocytes that facilitate HIV neuroinvasion. HIV-specific cannabis studies are necessary.

HIV Infection and Neurocognitive Disorders in the Context of Chronic Drug Abuse: Evidence for Divergent Findings Dependent upon Prior Drug History

The fronto-striatal circuitry, involving the nucleus accumbens, ventral tegmental area, and prefrontal cortex, mediates goal-directed behavior and is targeted by both drugs of abuse and HIV-1 infection. Acutely, both drugs and HIV-1 provoke increased dopamine activity within the circuit. However, chronic exposure to drugs or HIV-1 leads to dysregulation of the dopamine system as a result of fronto-striatal adaptations to oppose the effects of repeated instances of transiently increased dopamine. Specifically, chronic drug use leads to reduced dopaminergic tone, upregulation of dopamine transporters, and altered circuit connectivity, sending users into an allosteric state in which goal-directed behaviors are dysregulated (i.e., addiction). Similarly, chronic exposure to HIV-1, even with combination antiretroviral therapy (cART), dysregulates dopamine and dopamine transporter function and alters connectivity of the fronto-striatal circuit, contributing to apathy and clinical symptoms of HIV-1 associated neurocognitive disorders (HAND). Thus, in a drug user also exposed to HIV-1, dysregulation of the fronto-striatal dopamine circuit advances at an exacerbated rate and appears to be driven by mechanisms unique from those seen with chronic drug use or HIV-1 exposure alone. We posit that the effects of drug use and HIV-1 infection on microglia interact to drive the progression of motivational dysfunction at an accelerated rate. The current review will therefore explore how the fronto-striatal circuit adapts to drug use (using cocaine as an example), HIV-1 infection, and both together; emphasizing proper methods and providing future directions to develop treatments for pathologies disrupting goal-directed behaviors and improve clinical outcomes for affected patients. Graphical Abstract Drug use and HIV-1 in the fronto-striatal circuit. Drugs of abuse and HIV-1 infection both target the fronto-striatal circuit which mediates goal-directed behavior. Acutely, drugs and HIV-1 increase dopamine activity; in contrast chronic exposure produces circuit adaptions leading to dysregulation, addiction and/or apathy. Comorbid drug use and HIV-1 infection may interact with microglia to exacerbate motivational dysregulation.

Chronic HIV-1 Tat exposure alters anterior cingulate cortico-basal ganglia-thalamocortical synaptic circuitry, associated behavioral control, and immune regulation in male mice

HIV-1 selectively disrupts neuronal integrity within specific brain regions, reflecting differences in viral tropism and/or the regional differences in the vulnerability of distinct neuronal subpopulations within the CNS. Deficits in prefrontal cortex (PFC)-mediated executive function and the resultant loss of behavioral control are a particularly debilitating consequence of neuroHIV. To explore how HIV-1 disrupts executive function, we investigated the effects of 48 h, 2 and/or 8 weeks of HIV-1 Tat exposure on behavioral control, synaptic connectivity, and neuroimmune function in the anterior cingulate cortex (ACC) and associated cortico-basal ganglia (BG)-thalamocortical circuitry in adult, Tat transgenic male mice. HIV-1 Tat exposure increased novelty-exploration in response to novel food, flavor, and environmental stimuli, suggesting that Tat triggers increased novelty-exploration in situations of competing motivation (e.g., drive to feed or explore vs. fear of novel, brightly lit open areas). Furthermore, Tat induced adaptability in response to an environmental stressor and pre-attentive filtering deficits. The behavioral insufficiencies coincided with decreases in the inhibitory pre- and post-synaptic proteins, synaptotagmin 2 and gephyrin, respectively, in the ACC, and alterations in specific pro- and anti-inflammatory cytokines out of 23 assayed. The interaction of Tat exposure and the resultant time-dependent, selective alterations in CCL4, CXCL1, IL-12p40, and IL-17A levels in the PFC predicted significant decreases in adaptability. Tat decreased dendritic spine density and cortical VGLUT1 inputs, while increasing IL-1β, IL-6, CCL5, and CCL11 in the striatum. Alternatively, IL-1α, CCL5, and IL-13 were decreased in the mediodorsal thalamus despite the absence of synaptic changes. Thus, HIV-1 Tat appears to uniquely and systematically disrupt immune regulation and the inhibitory and excitatory synaptic balance throughout the ACC-BG-thalamocortical circuitry resulting in a loss of behavioral control.

Altered Brain Function in Young HIV Patients with Syphilis Infection: A Voxel-Wise Degree Centrality Analysis

Objective

This study assessed the possible effect of syphilis co-infection in the brain function in young HIV patients by using voxel-wise degree centrality (DC) analysis.

Methods

Forty-four syphilis-co-infected HIV patients (HIV+/syphilis+), 45 HIV patients without syphilis history (HIV+/syphilis-) and 43 matched healthy controls (HC) underwent resting-state fMRI examinations. Laboratory tests and a battery of neuropsychological tests were performed before each MRI examination. One-way ANOVA was used to compare the differences of DC among the three groups. The correlations between MRI metrics and laboratory/neuropsychological tests in each patient's group were performed by Pearson correlation analysis.

Results

Compared with HIV+/syphilis-, worse performance in complex motor skills was found in HIV+/syphilis+. Compared with HC, HIV+/syphilis+ and HIV+/syphilis- groups showed attenuated DC in the right orbital frontal cortex and increased DC in the left parietal/temporal cortex. Besides, we also found increased DC in the left inferior frontal cortex and bilateral posterior cingulated cortex/precuneus in HIV+/syphilis+ compared with HC. Moreover, compared with HIV+/syphilis-, HIV+/syphilis+ displayed decreased DC in the left middle occipital cortex. Additionally, in HIV+/syphilis+ group, the mean z value of DC was correlated to the CD4+ cell counts and the learning and delayed recall score.

Conclusion

Syphilis co-infection might be related to more brain functional reorganization in young HIV patients which could be reflected by DC value.

HIV, Depression, and Cognitive Impairment in the Era of Effective Antiretroviral Therapy

PURPOSE OF REVIEW

Mental health disorders, especially depression, are prevalent among people living with HIV (PLWH) and are associated with cognitive impairment (CI) among HIV-uninfected (HIV-) individuals. We conducted a comprehensive review of the link between depression and cognition among PLWH.

RECENT FINDINGS

Studies examining depression and cognition in PLWH report high rates of current (median = 24%) and lifetime depression (42%). There is reliable evidence that depression is associated with overall CI among PLWH, and in the cognitive domains of processing speed, executive function, learning and memory, and motor function. Although few studies have examined the interaction between HIV serostatus and depression on CI, there is no evidence of a stronger association between CI and depression in PLWH compared with HIV- controls. Depression is prevalent and reliably associated with CI in PLWH, with an overall pattern of domain-specific associations similar to that of HIV- individuals.

History of Alcohol Consumption and HIV Status Related to Functional Connectivity Differences in the Brain During Working Memory Performance

BACKGROUND

Poorer working memory function has previously been associated with alcohol misuse, Human Immunodeficiency Virus (HIV) positive status, and risky behavior. Poorer working memory performance relates to alterations in specific brain networks.

OBJECTIVE

The current study examined if there was a relationship between brain networks involved in working memory and reported level of alcohol consumption during an individual's period of heaviest use. Furthermore, we examined whether HIV status and the interaction between HIV and alcohol consumption was associated with differences in these brain networks.

METHODS

Fifty adults, 26 of whom were HIV positive, engaged in an n-back working memory task (0-back and 2-back trials) administered in a magnetic resonance imaging (MRI) scanner. The Kreek- McHugh-Schluger-Kellogg (KMSK) scale of alcohol consumption was used to characterize an individual's period of heaviest use and correlates well with their risk for alcohol dependence. Connectivity analyses were conducted using data collected during n-back task.

RESULTS

Functional connectivity differences associated with greater alcohol consumption included negative connectivity, primarily from parietal attention networks to frontal networks. Greater alcohol consumption was also associated with positive connectivity from working memory nodes to the precuneus and paracingulate. HIV positive status was associated with more nodes of negative functional connectivity relative to alcohol consumption history alone, particularly in the frontoparietal networks. The HIV positive individuals with heavier drinking history related to negative fronto-parietal connectivity, along with positive connectivity from working memory nodes to mesolimbic regions.

CONCLUSION

Findings allow for a better understanding of brain networks affected by HIV and alcohol and may provide avenues for interventions.

Increases in compulsivity, inflammation, and neural injury in HIV transgenic rats with escalated methamphetamine self-administration under extended-access conditions

The abuse of stimulants, such as methamphetamine (METH), is associated with treatment non-compliance, a greater risk of viral transmission, and the more rapid clinical progression of immunological and central nervous system human immunodeficiency virus (HIV) disease. The behavioral effects of METH in the setting of HIV remain largely uncharacterized. We used a state-of-the-art paradigm of the escalation of voluntary intravenous drug self-administration in HIV transgenic (Tg) and wildtype rats. The rats were first allowed to self-administer METH under short-access (ShA) conditions, which is characterized by a nondependent and more "recreational" pattern of METH use, and then allowed to self-administer METH under long-access (LgA) conditions, which leads to compulsive (dependent) METH intake. HIV Tg and wildtype rats self-administered equal amounts of METH under ShA conditions. HIV Tg rats self-administered METH under LgA conditions following a 4-week enforced abstinence period to model the intermittent pattern of stimulant abuse in humans. These HIV Tg rats developed greater motivation to self-administer METH and self-administered larger amounts of METH. Impairments in function of the medial prefrontal cortex (mPFC) contribute to compulsive drug and alcohol intake. Gene expression profiling of the mPFC in HIV Tg rats with a history of escalated METH self-administration under LgA conditions showed transcriptional evidence of increased inflammation, greater neural injury, and impaired aerobic glucose metabolism than wildtype rats that self-administered METH under LgA conditions. The detrimental effects of the interaction between neuroHIV and escalated METH intake on the mPFC are likely key factors in the greater vulnerability to excessive drug intake in the setting of HIV.

Supporting strategic processes can improve time-based prospective memory in the laboratory among older adults with HIV disease

OBJECTIVE

Older adults with HIV disease demonstrate moderate deficits in time-based prospective memory (PM), which is the strategically demanding ability of remembering to perform a task at a specific time. Using theories from the PM literature, we hypothesized that supporting strategic processes would improve time-based PM in the laboratory among HIV+ older adults.

METHOD

One hundred forty-five HIV+ participants were randomly assigned to a control condition or an experimental group in which strategic processing was supported at encoding (i.e., implementation intentions and visualization), monitoring (i.e., content-free cuing), and/or cue detection (i.e., auditory alarm). The HIV+ control group and 58 seronegative participants completed two ongoing language tasks with a time-based PM requirement. The HIV+ experimental groups underwent counterbalanced time-based PM trials under both control and strategically supported conditions.

RESULTS

The HIV+ cue-detection group showed a large within-subjects improvement, which was strongly related to lower scores on separate clinical time-based PM measure and was accompanied by a large reduction in clock-checking behavior. Results also revealed a small within-subjects improvement in time-based PM in the encoding condition.

CONCLUSIONS

Supporting strategic encoding and cue-detection processes in the laboratory can improve time-based PM deficits in older HIV+ adults, which may inform the development of more naturalistic PM-based interventions to enhance health behaviors. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Neural correlates of maintenance working memory, as well as relevant structural qualities, are associated with earlier antiretroviral treatment initiation in vertically transmitted HIV

There is evidence of HIV affecting cognitive functioning across age groups, with adult studies showing related deficits in frontostriatal and hippocampal regional activity. Additionally, delayed initiation of antiretroviral treatment (ART) has been associated with poorer cognitive outcomes in HIV-infected youth. Little is known, however, of the neural correlates underlying such cognitive deficits in youth populations. We investigated maintenance working memory-related brain activity in South African HIV-infected youth and controls, and the effect of ART initiation age on underlying structures. Sixty-four perinatally infected youth (ages 9-12) and 20 controls (ages 9-13) underwent functional magnetic resonance imaging (fMRI) while completing 1-back and 0-back blocks of the N-back task. At an uncorrected p value threshold of 0.001, the HIV-infected group showed decreased activation in the left superior temporal gyrus, pre- and postcentral gyri, insula, and putamen as well as bilateral hippocampus, and mid cingulum. The HIV patients with delayed ART initiation showed less activation during processing conditions in the mid cingulum; left inferior parietal gyrus; and right inferior frontal, bilateral thalamic, and superior temporal regions. When these regions were tested for structural differences, the mid cingulum and right inferior frontal gyrus, insula, and thalamus were found to have less cortical thickness, surface area, or volume in the group with delayed ART initiation. Regional differences between HIV-infected youth and controls noted in the N-back task are consistent with impairments in structures involved in maintenance working memory. These data support earlier ART initiation in perinatally infected individuals.

Dopaminergic impact of cART and anti-depressants on HIV neuropathogenesis in older adults

The success of combination antiretroviral therapy (cART) has transformed HIV infection into a chronic condition, resulting in an increase in the number of older, cART-treated adults living with HIV. This has increased the incidence of age-related, non-AIDS comorbidities in this population. One of the most common comorbidities is depression, which is also associated with cognitive impairment and a number of neuropathologies. In older people living with HIV, treating these overlapping disorders is complex, often creating pill burden or adverse drug-drug interactions that can exacerbate these neurologic disorders. Depression, NeuroHIV and many of the neuropsychiatric therapeutics used to treat them impact the dopaminergic system, suggesting that dopaminergic dysfunction may be a common factor in the development of these disorders. Further, changes in dopamine can influence the development of inflammation and the regulation of immune function, which are also implicated in the progression of NeuroHIV and depression. Little is known about the optimal clinical management of drug-drug interactions between cART drugs and antidepressants, particularly in regard to dopamine in older people living with HIV. This review will discuss those interactions, first examining the etiology of NeuroHIV and depression in older adults, then discussing the interrelated effects of dopamine and inflammation on these disorders, and finally reviewing the activity and interactions of cART drugs and antidepressants on each of these factors. Developing better strategies to manage these comorbidities is critical to the health of the aging, HIV-infected population, as the older population may be particularly vulnerable to drug-drug interactions affecting dopamine.

Elevated Depressive Symptoms Are a Stronger Predictor of Executive Dysfunction in HIV-Infected Women Than in Men

BACKGROUND

HIV-infected (HIV+) women seem to be more vulnerable to neurocognitive impairment (NCI) than HIV+ men, perhaps in part due to mental health factors. We assessed the association between elevated depressive symptoms and NCI among HIV+ and HIV-uninfected (HIV-) women and men.

SETTING

Women's Interagency HIV Study and Multicenter AIDS Cohort Study.

METHODS

Eight hundred fifty-eight HIV+ (429 women; 429 men) and 562 HIV- (281 women; 281 men) completed the Center for Epidemiologic Studies Depression (16 cutoff) Scale and measures of psychomotor speed/attention, executive, and motor function over multiple visits (or time points). Women's Interagency HIV Study and Multicenter AIDS Cohort Study participants were matched according to HIV status, age, race/ethnicity, and education. Generalized linear mixed models were used to examine interactions between biological sex, HIV serostatus, and depression on impairment (T-scores <40) after covariate adjustment.

RESULTS

Despite a higher frequency of depression among men, the association between depression and executive function differed by sex and HIV serostatus. HIV+ women with depression had 5 times the odds of impairment on a measure of executive control and inhibition versus HIV- depressed women and 3 times the odds of impairment on that measure versus HIV+ depressed men. Regardless of group status, depression was associated with greater impairment on processing speed, executive (mental flexibility), and motor function (P's < 0.05).

CONCLUSIONS

Depression contributes to NCI across a broad range of cognitive domains in HIV+ and HIV- individuals, but HIV+ depressed women show greater vulnerabilities in executive function. Treating depression may help to improve cognition in patients with HIV infection.

Heterogeneity in neurocognitive change trajectories among people with HIV starting antiretroviral therapy in Rakai, Uganda

Considerable heterogeneity exists in patterns of neurocognitive change in people with HIV (PWH). We examined heterogeneity in neurocognitive change trajectories from HIV diagnosis to 1-2 years post-antiretroviral therapy (ART). In an observational cohort study in Rakai, Uganda, 312 PWH completed a neuropsychological (NP) test battery at two-time points (ART-naïve, 1-2 years post-ART initiation). All NP outcomes were used in a latent profile analysis to identify subgroups of PWH with similar ART-related neurocognitive change profiles. In a subset, we examined subgroup differences pre-ART on cytokine and neurodegenerative biomarkers CSF levels. We identified four ART-related change subgroups: (1) decline-only (learning, memory, fluency, processing speed, and attention measures), (2) mixed (improvements in learning and memory but declines in attention and executive function measures), (3) no-change, or (4) improvement-only (learning, memory, and attention measures). ART-related NP outcomes that are most likely to change included learning, memory, and attention. Motor function measures were unchanged. Subgroups differed on eight of 34 pre-ART biomarker levels including interleukin (IL)-1β, IL-6, IL-13, interferon-γ, macrophage inflammatory protein-1β, matrix metalloproteinase (MMP)-3, MMP-10, and platelet-derived growth factor-AA. The improvement-only and mixed subgroups showed lower levels on these markers versus the no-change subgroup. These findings provide support for the need to disentangle heterogeneity in ART-related neurocognitive changes, to focus on higher-order cognitive processes (learning, memory, attention) as they were most malleable to change, and to better understand why motor function remained unchanged despite ART treatment. Group differences in pre-ART CSF levels provide preliminary evidence of biological plausibility of neurocognitive phenotyping.