Biology subjects

Aarabi, M. H.

Publications and source records attributed to Aarabi, M. H..

3 recordsLinked to original sources

bioRxiv2025

Structural Connectome Dimension Shapes Brain Dynamics in Health and Disease

The structural connectome serves as the foundation for neural information signaling, playing a primary constraint on brain functionality. Yet, its influence on emergent dynamical properties is not fully understood. Generally, a key measure of a systems structural impact on dynamical phenomena is its dimension. By tracking the temporal evolution of diffusive perturbations, we estimate a scale-dependent measure of dimension of empirical connectomes. At the local scale, it is highly heterogeneous and follows a gradient from sensory-motor to high-cognitive areas. At the global scale, it encapsulates mesoscale topological information related to the balance between segregation and integration. Furthermore, by comparing connectomes from stroke patients, we find that dimension captures the local effects of lesions and, at a global level, is linked to impaired critical patterns and decreased cognitive performance. Overall, the dimension of the connectome may serve as a powerful descriptor for bridging the gap between structure and function in the human brain.

neuroscience↗

bioRxiv2023

White Matter Correlates of Impulsive Behavior in Healthy Individuals: A Diffusion MRI Study

BackgroundImpulsivity is closely related to the tendency to engage in risky behaviors. Previous research identified macrostructural brain alterations in individuals exhibiting impulsive behaviors. Understanding the microstructural brain changes linked to impulsivity can elucidate its underlying mechanisms and guide effective treatment strategies. In this study, we employed diffusion magnetic resonance imaging (DMRI) connectometry to investigate white matter tracts associated with impulsivity while considering potential sex differences. MethodsWe enrolled 218 healthy participants from the Leipzig Study for Mind-Body-Emotion Interactions (LEMON) database. Correlations between DMRI-derived white matter changes and impulsivity were assessed using scores from the UPPS Impulsive Behavior Scales four subscales (lack of perseverance (PE), lack of premeditation (PM), sensation seeking (SS), and negative urgency (NU)). ResultsOur findings revealed negative correlations between quantitative anisotropy (QA) values in bilateral cerebellum, middle cerebellar peduncle (MCP), and the severity of PE and PM across the cohort. Additionally, QA values within MCP, corpus callosum (CC) body, and forceps major exhibited negative correlations with SS. Conversely, QA values in forceps minor were positively correlated with PM, and QA values in both the forceps minor and bilateral cingulum showed positive correlations with SS. Remarkably, the observed correlations between UPPS subscale scores and QA value alterations within white matter tracts varied between males and females. ConclusionsImpulsivity is correlated with discernible alterations in white matter integrity across diverse tracts, including CC, cerebellum, and cingulum. Moreover, males and females show distinct patterns of correlations between white matter integrity and impulsivity. HighlightsO_LIImpulsivity is associated with QA changes and white matter alterations in various brain tracts. C_LIO_LILower white matter integrity in the cerebellum is negatively correlated with impulsivity. C_LIO_LIQA values in the CC parts showed divergent correlations with impulsive behavior. C_LIO_LIThe patterns of correlations across various tracts varied between males and females. C_LI

neuroscience↗

bioRxiv2018

Association between peripheral neuroinflammation and DATSCAN data of the striatal nuclei in Parkinson Disease

The interplay between peripheral and central inflammation has a significant role in dopaminergic neural death in nigrostriatal pathway, although no direct assessment of inflammation has been performed in relation to dopaminergic neuronal loss in striatal nuclei. In this study, the correlation of neutrophil to lymphocyte ratio (NLR) as a marker of peripheral inflammation to striatal binding ratios (SBR) of DAT-SPECT images in bilateral caudate and putamen nuclei were calculated in 388 drug-naive early PD patients (288 tremor-dominant, 73 PIGD, and 27 intermediate) and 148 controls. NLR was significantly higher in PD patients than age and sex-matched healthy controls. NLR showed a negative correlation to SBR in bilateral putamen in all PD subjects. Among our three subgroups, only TD subgroup showed remarkable results. A positive association between NLR and motor severity was observed in TD subgroup. Besides, NLR could negatively predict the SBR in ipsilateral and contralateral putamen and caudate nuclei in tremulous phenotype. Nonetheless, we found no significant association between NLR and other clinical and imaging findings in PIGD and intermediate subgroups, supporting the presence of distinct underlying pathologic mechanisms between tremor and non-tremor predominant PD at early stages of the disease.

neuroscience↗