Mapping Directional Connectivity in Resting-State fMRI Using Dynamic Causal Modeling in Matched Healthy Controls for Hypothalamic Hamartoma Patients

<p class="p1">Hypothalamic hamartoma (HH)&ndash;related epilepsy is increasingly understood as a disorder of <span class="s1">distributed neural networks rather than a focal lesion. While resting-state fMRI (rs-fMRI) has </span>enabled mapping of functional connectivity within these networks, traditional approaches remain correlational and do not capture directionality. Dynamic Causal Modeling (DCM) <span class="s1">addresses this limitation by estimating effective connectivity, allowing inference of directed </span>interactions between brain regions. <p class="p1">In this study, rs-fMRI data from 58 healthy controls were analyzed to establish normative effective connectivity within the hypothalamic&ndash;hippocampal circuit. Regions of interest <span class="s1">included the hypothalamus and bilateral hippocampal heads, with connectivity parameters </span>estimated using cross-spectral DCM. <p class="p1">Results demonstrated consistent intrinsic self-inhibition across regions and modest, bidirectional extrinsic connectivity with continuous interindividual variability. Notably, <span class="s1">hippocampal regions exerted a more stable influence on hypothalamic activity than the </span>reverse, though overall directional asymmetry remained minimal. <p class="p1">These findings define a normative baseline of directional connectivity, providing a critical reference for identifying pathological network alterations in HH-related epilepsy.