Accurate alignment of hippocampal anatomy across individuals remains challenging due to complex and highly variable folding patterns that are not well captured by conventional volumetric approaches. HippUnfold introduced a surface-based representation of the hippocampus, but key components—including coordinate estimation and inter-subject correspondence—were defined in the volumetric domain, making them susceptible to topological errors and interpolation artifacts. Here, we introduce a surface-intrinsic formulation of hippocampal unfolding in which geometry, intrinsic coordinates, and correspondence are defined directly on subject-specific surface manifolds. Intrinsic anterior–posterior and proximal–distal coordinates are computed by solving Laplace equations on the surface, and correspondence is established through surface-based resampling in unfolded space, replacing inverse volumetric warping. Relative to the original HippUnfold approach, this formulation improves test–retest consistency, subject identifiability, and mesh quality, while better preserving subject-specific gyral and sulcal morphology. Surface representations show reduced distortion between folded and unfolded spaces and eliminate misplaced or outlier vertices associated with volumetric warping. These improvements translate to enhanced sensitivity in a clinical application, improving lateralization of temporal lobe epilepsy. These results demonstrate that a surface-intrinsic formulation provides a principled and robust foundation for hippocampal unfolding, enabling topology-preserving alignment and more accurate characterization of inter-individual variability in health and disease.
J. DeKraker, D. Bansal, M. Snyder et al.· bioRxiv· 0 citations
OBJECTIVE
In temporal lobe epilepsy (TLE), patients often present with neurobehavioral comorbidities encompassing affective and cognitive difficulties. Whereas the latter have been related to atypical connectivity of mesiotemporal and frontotemporal circuits, the brain basis of affective symptoms remains incompletely understood. Here, we assessed functional network substrates of affective symptoms and examined their relationship to structural magnetic resonance imaging (MRI), cognition, and clinical parameters.
METHODS
We studied 42 drug-resistant patients who underwent multimodal 3-T MRI as well as self-report questionnaires of affective and cognitive functions outside the scanner, alongside 41 age- and sex-matched healthy controls. Partial least squares (PLS), a brain-wide multivariate associative technique, examined relationships between resting-state functional MRI connectivity strength (FCS) and affective measures. Linear models assessed relationships with morphology and microstructure, as well as cognitive and clinical parameters.
RESULTS
Moderate to severe anxiety was present in 79% of patients, with concealing and adjustment as coping strategies, and 40% experienced depression. Quality of life scores were below published norm for epilepsy. PLS analysis revealed a latent component that accounted for 67% of the covariance between FCS and affective symptoms, linking weaker connectivity in temporoparietal and prefrontal cortices, as well as mesiotemporal, thalamic, and pallidal regions, to anxiety, low energy/fatigue, medication-related complaints, and reduced quality of life. Among cognitive domains, verbal memory positively correlated with the same brain areas. Cortices with the strongest covariance between FCS and affective variables presented with marked atrophy and myelin alterations (indexed by T1/fluid-attenuated inversion recovery decreases). Controlling for verbal memory and metrics of brain structure, the temporal-parietal network remained the most compromised.
SIGNIFICANCE
Dysconnectivity of the temporal-parietal network emerges as a key contributor to affective symptoms in TLE, and limbic network dysfunction additionally impacts cognition. These findings emphasize the importance of multidisciplinary care targeting both emotion regulation and stress reduction, alongside cognitive rehabilitation, for improved well-being and quality of life.
F. Fadaie, B. Caldairou, Boris C. Bernhardt et al.· Epilepsia· 0 citations
HippoGenes provides a framework for exploring the molecular organization of the hippocampus, opening avenues for multiscale integration in health and disease, and is openly available on https://hippogenes.readthedocs.io.
A. Ngo, Sara Larivière, J. Royer et al.· bioRxiv· 0 citations
These findings provide robust evidence that multiscale MRI profiling can identify FCD signatures and contribute to in-vivo subtyping and the novel use of myeloarchitecture profiling and contextualization with macro-scale brain gradients provides new avenues to understand intracortical alterations and the embedding of FCD lesions into broader organizational patterns.
E. Sahlas, Judy Chen, Arielle Dascal et al.· bioRxiv· 0 citations
Multi-site findings demonstrate marked thalamic circuit fragmentation in TLE, and robustly showed subdivision-specific effects, which point to both mesiotemporal co-lateralization as well as broader system-level involvement.
Rui Ding, K. Xie, Judy Chen et al.· bioRxiv· 0 citations
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