Person: Vial Undurraga, Felipe
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Vial Undurraga
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Felipe
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Publication Identifying transcranial magnetic stimulation induced EEG signatures of different neuronal elements in primary motor cortex(2022) Ni, Zhen; Pajevic, Sinisa; Chen, Li; Leodori, Giorgio; Vial Undurraga, Felipe; Avram, Alexandru V.; Zhang, Yong; Mc Gurrin, Patrick; Cohen, Leonardo G.; Basser, Peter J.; Hallett, MarkObjective: To investigate the neuronal elements involved in the activation of corticospinal neurons in the primary motor cortex (M1). Methods: We studied 10 healthy subjects. Cortical evoked potentials with different components induced by monophasic transcranial magnetic stimulation (TMS) in anterior-posterior and posterior-anterior currents recorded with electroencephalography (EEG) were analyzed. Results: EEG signatures with P25 and N45 components recorded at the C3 electrode with posterior-anterior current were larger than those with anterior-posterior current, while the signatures with P180 and N280 components recorded at the FC1 electrode with anterior-posterior current were larger than those with posterior-anterior current. The source localization analysis revealed that the cortical evoked potential with anterior-posterior current distributed both in the M1 and premotor cortex while that with posterior-anterior current only located in the M1. Conclusions: We conclude that the activation of corticospinal pyramidal neurons in the M1 is affected by various neuronal elements including the local intracortical circuits in the M1 and inputs from premotor cortex with different sensitivities to TMS in opposite current directions. Significance: Our finding helped answer a longstanding question about how the corticospinal pathway from the M1 is functionally organized and activated.Publication Deep phenotyping of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome(2024) Walitt, Brian; Singh, Komudi; LaMunion, Samuel; Hallett , Mark; Jacobson, Steve; Chen, Kong; Enose-Akahata, Yoshimi; Apps, Richard; Barb, Jennifer; Bedard, Patrick; Brychta, Robert; Buckley, Ashura; Burbelo, Peter; Calco, Brice; Cathay, Brianna; Chen, Li; Chigurupati, Snigdha; Chen, Jinguo; Cheung, Foo; Chin, Lisa; Coleman, Benjamin; Courville, Amber; Deming, Madeleine; Drinkard, Bart; Feng, Li; Ferrucci, Luigi; Gabel, Scott; Gavin, Angelique; Goldstein, David; Hassanzadeh, Shahin; Horan, Sean; Horovitz, Silvina; Johnson, Kory; Govan, Anita; Knutson, Kristine; Kreskow, Joy; Levin, Mark; Lyons, Jonathan; Madian, Nicholas; Vial Undurraga, FelipePost-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS) is a disabling disorder, yet the clinical phenotype is poorly defined, the pathophysiology is unknown, and no disease-modifying treatments are available. We used rigorous criteria to recruit PI-ME/CFS participants with matched controls to conduct deep phenotyping. Among the many physical and cognitive complaints, one defining feature of PI-ME/CFS was an alteration of effort preference, rather than physical or central fatigue, due to dysfunction of integrative brain regions potentially associated with central catechol pathway dysregulation, with consequences on autonomic functioning and physical conditioning. Immune profiling suggested chronic antigenic stimulation with increase in naïve and decrease in switched memory B-cells. Alterations in gene expression profiles of peripheral blood mononuclear cells and metabolic pathways were consistent with cellular phenotypic studies and demonstrated differences according to sex. Together these clinical abnormalities and biomarker differences provide unique insight into the underlying pathophysiology of PI-ME/CFS, which may guide future intervention.