Tobias D. Merson, Ph.D.| Staff Scientist | toby.merson@nih.gov

Toby received his Ph.D. from the University of Melbourne, where he studied epigenetic regulation of adult neural stem cells and neurogenesis under the mentorship of Professors Anna Voss, Tim Thomas, and Perry Bartlett at the Walter and Eliza Hall Institute of Medical Research. He completed postdoctoral training with Professor Trevor Kilpatrick at the Florey Institute of Neuroscience and Mental Health in Melbourne, establishing a novel mouse model of multiple sclerosis and exploring disease-associated changes in central nervous system stem cell function. From 2011 to 2022, he established and led independent research groups in Australia, first as Laboratory Head at the Florey Institute of Neuroscience and Mental Health, then as a tenured Group Leader at the Australian Regenerative Medicine Institute at Monash University. In May 2022, he joined the National Institute of Mental Health Intramural Research Program as a Staff Scientist, where he leads the Oligodendroglial Interactions Group. His research investigates how disruptions in oligodendroglial cell function and myelination contribute to mental health disorders, with particular emphasis on understanding how myelin plasticity influences learning, memory, and experience-dependent neuroplasticity.

Dr. Tomás Mediavilla, Ph.D. | Postdoctoral Fellow | tomas.mediavillacarranza@nih.gov

Tomás earned his B.Sc. in Biology from the University of La Laguna in Tenerife, Spain, before relocating to Sweden to pursue graduate studies at Umeå University. He completed his M.Sc. in Molecular Biology in 2019 and his Ph.D. in Medical Science (Histology and Cell Biology) in 2023 under the supervision of Dr. Daniel Marcellino, where his research focused on adaptive myelination and structural brain changes associated with learning. In November 2023, Tomás joined the Oligodendroglial Interactions Group at the NIMH as a Postdoctoral IRTA Visiting Fellow. His current research focuses on experience-dependent myelination, with particular interest in understanding how early-life adversity, including parental neglect and social deprivation, impacts neurodevelopment and prefrontal cortex myelination, which has important implications for understanding the biological basis of mental health disorders.

John Carlo Combista, M.Sc. | Predoctoral Fellow | johncarlo.combista@nih.gov

Carlo earned his B.S. in Pharmacy and Clinical Pharmaceutical Sciences in 2015 from the University of San Carlos in the Philippines, where he became a registered pharmacist. He then pursued a research career in neuroscience, completing his M.Sc. in Medical Sciences with a major in Neuroscience at Tel Aviv University under the mentorship of Dr. Nathan Dascal. His master's research explored the biophysical properties of G protein-coupled inwardly rectifying potassium channels (GIRKs) as potential therapeutic targets for GNB1 syndrome. Carlo is currently pursuing his Ph.D. in Neuroscience and Cognitive Science at the University of Maryland, College Park. In August 2023, he joined the Oligodendroglial Interactions Group at the NIMH, where his research focuses on understanding the topography and spatial organization of oligodendrocytes in central nervous system white matter, particularly their characteristic arrangement into regularly spaced linear arrays of cells in tandem alignment.

Diya Rai-Gersappe, B.A. | Post-baccalaureate Fellow | diya.rai-gersappe@nih.gov

Diya received her B.A. in Neuroscience and Behavior and French and Francophone Studies from Vassar College in May 2024. During her undergraduate studies, she worked in Dr. Lori Newman's lab investigating the role of astrocytes in cognition, spatial working memory, and attention. She also conducted research at Stony Brook University with Dr. Miriam Rafailovich, focusing on designing an injectable hydrogel for outpatient treatment of intracranial aneurysms. In August 2024, Diya joined the Oligodendroglial Interactions Group at the NIMH as a Post-baccalaureate IRTA Fellow. Her current research examines the roles of oligodendrocyte precursor cells (OPCs) and microglia in the development of anxiety- and depression-like conditions, as well as the potential involvement of OPCs in mood regulation. Following her fellowship, she plans to pursue an M.D. with a special interest in psychiatry.

Jade Tai, B.A. | Post-baccalaureate Fellow | jade.tai@nih.gov

Jade earned her B.A. in Psychology with a minor in Applied Developmental Psychology from the University of California, Los Angeles in September 2024. During her undergraduate studies, she worked in Dr. Steve S. Lee's lab investigating the influence of familial dynamics on ADHD development in children. In October 2024, Jade joined the Oligodendroglial Interactions Group at the NIMH as a Post-baccalaureate Fellow. Her current research focuses on studying activity-dependent mechanisms of adaptive myelination in motor development, exploring how neural activity and experience shape the formation and modification of myelin during motor skill acquisition. Following her fellowship at OIG, she plans to pursue an M.D. degree.