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 (
Cognitive training may partially reverse cognitive deficits in people with HIV (PWH). Previous functional MRI (fMRI) studies demonstrate that working memory training (WMT) alters brain activity during working memory tasks, but its effects on resting brain network organization remain unknown.
To test whether WMT affects PWH brain functional connectivity in resting‐state fMRI (rsfMRI).
Prospective.
A total of 53 PWH (ages 50.7 ± 1.5 years, two women) and 53
Axial single‐shot gradient‐echo echo‐planar imaging at 3.0 T was performed at baseline (TL1), at 1‐month (TL2), and at 6‐months (TL3), after WMT.
All participants had rsfMRI and clinical assessments (including neuropsychological tests) at TL1 before randomization to Cogmed WMT (adaptive training,
Two‐way analyses of variance (ANOVA) on GT metrics and two‐sample
The ventral default mode network (vDMN) eCent differed between PWH and SN groups at TL1 but not at TL2 (
ICA and GT analyses showed that adaptive WMT normalized graph properties of the vDMN in PWH.
1
1
- Award ID(s):
- 1631838
- NSF-PAR ID:
- 10405630
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Magnetic Resonance Imaging
- Volume:
- 57
- Issue:
- 5
- ISSN:
- 1053-1807
- Page Range / eLocation ID:
- p. 1552-1564
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract 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. -
more » « less
Abstract HIV‐infection has been associated with widespread alterations in brain structure and function, although few studies have examined whether such aberrations are co‐localized and the degree to which clinical and cognitive metrics are related. We examine this question in the somatosensory system using high‐resolution structural MRI (sMRI) and magnetoencephalographic (MEG) imaging of neural oscillatory activity. Forty‐four participants with HIV (PWH) and 55 demographically‐matched uninfected controls completed a paired‐pulse somatosensory stimulation paradigm during MEG and underwent 3T sMRI. MEG data were transformed into the time‐frequency domain; significant sensor level responses were imaged using a beamformer. Virtual sensor time series were derived from the peak responses. These data were used to compute response amplitude, sensory gating metrics, and spontaneous cortical activity power. The T1‐weighted sMRI data were processed using morphological methods to derive cortical thickness values across the brain. From these, the cortical thickness of the tissue coinciding with the peak response was estimated. Our findings indicated both PWH and control exhibit somatosensory gating, and that spontaneous cortical activity was significantly stronger in PWH within the left postcentral gyrus. Interestingly, within the same tissue, PWH also had significantly reduced cortical thickness relative to controls. Follow‐up analyses indicated that the reduction in cortical thickness was significantly correlated with CD4 nadir and mediated the relationship between HIV and spontaneous cortical activity within the left postcentral gyrus. These data indicate that PWH have abnormally strong spontaneous cortical activity in the left postcentral gyrus and such elevated activity is driven by locally reduced cortical gray matter thickness.
-
more » « less
Background Healthy articular cartilage presents structural gradients defined by distinct zonal patterns through the thickness, which may be disrupted in the pathogenesis of several disorders. Analysis of textural patterns using quantitative MRI data may identify structural gradients of healthy or degenerating tissue that correlate with early osteoarthritis (OA).
Purpose To quantify spatial gradients and patterns in MRI data, and to probe new candidate biomarkers for early severity of OA.
Study Type Retrospective study.
Subjects Fourteen volunteers receiving total knee replacement surgery (eight males/two females/four unknown, average age ± standard deviation: 68.1 ± 9.6 years) and 10 patients from the OA Initiative (OAI) with radiographic OA onset (two males/eight females, average age ± standard deviation: 57.7 ± 9.4 years; initial Kellgren‐Lawrence [KL] grade: 0; final KL grade: 3 over the 10‐year study).
Field Strength/Sequence 3.0‐T and 14.1‐T, biomechanics‐based displacement‐encoded imaging, fast spin echo, multi‐slice multi‐echo
T2 mapping.Assessment We studied structure and strain in cartilage explants from volunteers receiving total knee replacement, or structure in cartilage of OAI patients with progressive OA. We calculated spatial gradients of quantitative MRI measures (eg, T2) normal to the cartilage surface to enhance zonal variations. We compared gradient values against histologically OA severity, conventional relaxometry, and/or KL grades.
Statistical Tests Multiparametric linear regression for evaluation of the relationship between residuals of the mixed effects models and histologically determined OA severity scoring, with a significance threshold at
α = 0.05.Results Gradients of individual relaxometry and biomechanics measures significantly correlated with OA severity, outperforming conventional relaxometry and strain metrics. In human explants, analysis of spatial gradients provided the strongest relationship to OA severity (
R 2 = 0.627). Spatial gradients of T2 from OAI data identified variations in radiographic (KL Grade 2) OA severity in single subjects, while conventional T2 alone did not.Data Conclusion Spatial gradients of quantitative MRI data may improve the predictive power of noninvasive imaging for early‐stage degeneration.
Evidence Level 1
Technical Efficacy Stage 1
-
more » « less
Abstract People with HIV (PWH) use cannabis at a higher rate than the general population, but the influence on neural activity is not well characterized. Cannabis use among PWH may have a beneficial effect, as neuroinflammation is known to be a critical problem in PWH and cannabis use has been associated with a reduction in proinflammatory markers. Thus, it is important to understand the net impact of cannabis use on brain and cognitive function in PWH. In this study, we collected magnetoencephalographic (MEG) brain imaging data on 81 participants split across four demographically matched groups (i.e., PWH using cannabis, controls using cannabis, non‐using PWH, and non‐using controls). Participants completed a visuospatial processing task during MEG. Time–frequency resolved voxel time series were extracted to identify the dynamics of oscillatory and pre‐stimulus baseline neural activity. Our results indicated strong theta (4–8 Hz), alpha (10–16 Hz), and gamma (62–72 Hz) visual oscillations in parietal–occipital brain regions across all participants. PWH exhibited significant behavioral deficits in visuospatial processing, as well as reduced theta oscillations and elevated pre‐stimulus gamma activity in visual cortices, all of which replicate prior work. Strikingly, chronic cannabis use was associated with a significant reduction in pre‐stimulus gamma activity in the visual cortices, such that PWH no longer statistically differed from controls. These results provide initial evidence that cannabis use may normalize some neural aberrations in PWH. This study fills an important gap in understanding the impact of cannabis use on brain and cognitive function in PWH.
-
more » « less
Background Brain tissue hypoxia is a common consequence of traumatic brain injury (TBI) due to the rupture of blood vessels during impact and it correlates with poor outcome. The current magnetic resonance imaging (MRI) techniques are unable to provide a direct map of tissue hypoxia.
Purpose To investigate whether GdDO3NI, a nitroimidazole‐based T1MRI contrast agent allows imaging hypoxia in the injured brain after experimental TBI.
Study Type Prospective.
Animal Model TBI‐induced mice (controlled cortical impact model) were intravenously injected with either conventional T1agent (gadoteridol) or GdDO3NI at 0.3 mmol/kg dose (
n = 5 for each cohort) along with pimonidazole (60 mg/kg) at 1 hour postinjury and imaged for 3 hours following which they were euthanized.Field Strength/Sequence 7 T/T2‐weighted spin echo and T1‐weighted gradient echo.
Assessment Injured animals were imaged with T2‐weighted spin‐echo sequence to estimate the extent of the injury. The mice were then imaged precontrast and postcontrast using a T1‐weighted gradient‐echo sequence for 3 hours postcontrast. Regions of interests were drawn on the brain injury region, the contralateral brain as well as on the cheek muscle region for comparison of contrast kinetics. Brains were harvested immediately post‐imaging for immunohistochemical analysis.
Statistical Tests One‐way analysis of variance and two‐sample
t ‐tests were performed with aP < 0.05 was considered statistically significant.Results GdDO3NI retention in the injury region at 2.5–3 hours post‐injection was significantly higher compared to gadoteridol (mean retention fraction 63.95% ± 27.43% vs. 20.68% ± 7.43% for gadoteridol at 3 hours) while it rapidly cleared out of the muscle region. Pimonidazole staining confirmed the presence of hypoxia in both gadoteridol and GdDO3NI cohorts, and the later cohort showed good agreement with MRI contrast enhancement.
Data Conclusion GdDO3NI was successfully shown to visualize hypoxia in the brain post‐TBI using T1‐weighted MRI at 2.5–3 hours postcontrast.
Evidence Level 1
Technical Efficacy Stage 1
