Articles by Timothy J. Petros in JoVE
Homochronic Transplantation of Interneuron Precursors into Early Postnatal Mouse Brains Giulia Quattrocolo1, Maria Isaac2, Yajun Zhang2, Timothy J. Petros2 1Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, 2Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Challenging young neurons in new brain regions can reveal important insights into how the environment sculpts neuronal fate and maturation. This protocol describes a procedure to harvest interneuron precursors from specific brain regions and transplant them either homotopically or heterotopically into the brain of postnatal pups.
Other articles by Timothy J. Petros on PubMed
Heterotopic Transplantations Reveal Environmental Influences on Interneuron Diversity and Maturation Cell Reports. | Pubmed ID: 29045839 During embryogenesis, neural progenitors in the ganglionic eminences give rise to diverse GABAergic interneuron subtypes that populate all forebrain regions. The extent to which these cells are genetically predefined or determined by postmigratory environmental cues remains unknown. To address this question, we performed homo- and heterotopic transplantation of early postnatal MGE-derived cortical and hippocampal interneurons. Grafted cells migrated, and displayed neurochemical, electrophysiological, morphological, and neurochemical profiles similar to endogenous interneurons. Our results indicate that the host environment regulates the proportion of interneuron classes in the brain region. However, some specific interneuron subtypes retain characteristics representative of their donor brain regions.
Stranger in a Strange Land: Using Heterotopic Transplantations to Study Nature Vs Nurture in Brain Development Journal of Experimental Neuroscience. | Pubmed ID: 29511360 The mammalian brain develops from a simple sheet of neuroepithelial cells into an incredibly complex structure containing billions of neurons with trillions of synapses. Understanding how intrinsic genetic programs interact with environmental cues to generate neuronal diversity and proper connectivity is one of the most daunting challenges in developmental biology. We recently explored this issue in forebrain GABAergic inhibitory interneurons, an extremely diverse population of neurons that are classified into distinct subtypes based on morphology, neurochemical markers, and electrophysiological properties. Immature interneurons were harvested from one brain region and transplanted into a different region, allowing us to assess how challenging cells in a new environment affected their fate. Do these grafted cells adopt characteristics of the host environment or retain features from the donor environment? We found that the proportion of interneuron subgroups is determined by the host region, but some interneuron subtypes maintain features attributable to the donor environment. In this commentary, I expound on potential mechanisms that could underlie these observations and explore the implications of these findings in a greater context of developmental neuroscience.