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Galovic, M.

Publications and source records attributed to Galovic, M..

3 recordsLinked to original sources

A Brain Circuit for Status Epilepticus

Status epilepticus (SE) is a life-threatening persistent epileptic seizure that can arise from various brain structures, leaving its brain circuit unknown. In this study, we utilize brain imaging changes during SE to reveal the brain architecture and circuit of persistent seizures. Multimodal lesion mapping identified that brain imaging changes during SE localize to a specific predisposed brain architecture characterized by increased metabolic rate, high synaptic and mitochondrial density, glutamate (mGLUR5 and NMDA) and GABA receptors. Gene expression patterns within lesion locations revealed a transcriptomic profile enriched for epilepsy pathologies (including SE), neuronal and synaptic processes, and glutamate signaling. Lesion network mapping demonstrated these same lesions map to a common brain circuit, unifying a traditionally heterogeneous patient population. Findings were validated in an independent cohort and the identified SE circuit distinguished brain imaging changes during SE from other lesion etiologies with excellent accuracy (91%), significantly outperforming all other tested maps. With this SE circuit, we identify therapeutic targets for precision therapy that could modulate this circuit. This study demonstrates brain imaging changes in SE converge on a unified brain circuit that could help diagnostic workup of patients in critical care and guide clinical trials of precision therapy for persistent seizures.

neuroscience↗

Sex-related structural alterations across common epilepsies: a worldwide ENIGMA study

Epilepsy is characterized by widespread structural brain alterations extending beyond the epileptic zone, involving both cortical and subcortical regions. Importantly, the clinical manifestation of epilepsy, including seizure types, psychiatric comorbidities, and treatment responses, has been shown to differ between sexes. However, sex differences in structural alterations in epilepsy have been seldomly reported in neuroimaging studies, partly due to limited sample sizes and single-center designs. Here, we systematically investigated sex differences in common epilepsies and their related clinical variables using structural neuroimaging biomarkers in an international multi-center cohort of 1,253 epilepsy patients and 1,077 healthy controls. We studied cortical thickness and subcortical volume in two types of epilepsy: temporal lobe epilepsy (TLE) and genetic generalized epilepsy (GGE). Both male and female patients with TLE showed widespread cortical and subcortical thinning compared with controls. In GGE, when compared separately to controls, male patients showed only subtle structural alterations, whereas female patients exhibited more widespread structural alterations. Sex-stratified analyses revealed some variation in the extent and distribution of cortical thickness and subcortical volume alterations between male and female patients in both epilepsy cohorts. Yet, we did not find significant sex-by-diagnosis interaction effects in TLE and GGE. Similarly, no significant interaction effects were observed between sex and age of onset or disease duration in either patient group. Overall, although we observed some differences in regional cortical thickness and subcortical volume between male and female patients with epilepsy, we did not find significant sex-by-diagnosis interactions. Our findings indicate that sex differences in behavioral and clinical outcomes of epilepsy may involve biological or functional processes that require further investigation.

neuroscience↗

Inter-individual variability of neurotransmitter receptor and transporter density in the human brain

Neurotransmitter receptors guide the propagation of signals between brain regions. Mapping receptor distributions in the brain is therefore necessary for understanding how neurotransmitter systems mediate the link between brain structure and function. Normative receptor density can be estimated using group averages from Positron Emission Tomography (PET) imaging. However, the generalizability and reliability of group-average receptor maps depends on the inter-individual variability of receptor density, which is currently unknown. Here we collect group standard deviation brain maps of PET-estimated protein abundance for 12 different neurotransmitter receptors and transporters across 7 neurotransmitter systems, including dopamine, serotonin, acetylcholine, glutamate, GABA, cannabinoid, and opioid. We illustrate how cortical and subcortical inter-individual variability of receptor and transporter density varies across brain regions and across neurotransmitter systems. We complement inter-individual variability with inter-regional variability, and show that receptors that vary more across brain regions than across individuals also demonstrate greater out-of-sample spatial consistency. Altogether, this work quantifies how receptor systems vary in healthy individuals, and provides a means of assessing the generalizability of PET-derived receptor density quantification.

neuroscience↗