Director of the School: Antonio M. Battro
Director of the Course: Sebastián J. Lipina
Codirectors of the Course: Eric Pakulak, María Soledad Segretin
Management Assistance of the Course: Matías Lopez-Rosenfeld
Program Officer of the School: Lula Majdalani
I am currently an Associate Professor at the Vrije Universiteit Amsterdam, The Netherlands in the Center for Neurogenomics and Cognitive Research. The aim of my group’s research has been to study how synaptic transmission and plasticity of synaptic contacts changes during key periods of development in the brain. Furthermore, we aim to understand changes in neurodevelopmental brain disorders, such as intellectual disability, and the underlying mechanisms at cellular and network levels of processing. We use genetically-engineered mouse models and in recent years, have taken the opportunity to also record functional activity of human neurons either derived from stem cells of patient populations or from brain tissue samples donated by surgical patients.
Critical and sensitive periods in the brain: neurotypical development and neurodevelopmental brain disorders
Critical and sensitive periods of the brain are specific time-windows of early development during which systems in the brain, from synapse formation to behavioural phenotypes, are most subject to change. Understanding these developmental periods and their underlying mechanisms provides a framework not only for mapping neurotypical brain maturation but also for altered developmental trajectories in neurodevelopmental brain disorders (NDDs). Using mouse models for specific genetic syndromes, we have focused on understanding the effects of single NDD genetic mutations upon synaptic and neuronal phenotypes over the course of brain development. Examples of phenotypes include altered neuronal connectivity, imbalances in synaptic excitation and inhibition and hyperexcitability of neuronal networks in the brain. These phenotypes may occur significantly earlier than previously thought, during so-called ‘presymptomatic’ stages when prominent behavioural phenotypes are not apparent. Furthermore, many such phenotypes are transient, implying the existence of potential compensatory mechanisms in the brain – although not without later developmental consequences for the organism. Finally, we propose that the concept of dysregulated critical and sensitive periods underlying NDDs may act as a unifying framework for other prominent theories focusing on the neurobiological bases of these disorders.
Literature to share
• Meredith, R.M. (2015). Sensitive and critical periods during neurotypical and aberrant neurodevelopment: A framework for neurodevelopmental disorders. Neuroscience and Biobehavioral Reviews, 50, 180–188, doi.org/ 10.1016/ j.neubiorev.2014.12.001.
• Meredith, R.M., Dawitz, J., & Kramvis, I. (2012). Sensitive time-windows for susceptibility in neurodevelopmental disorders. Trends in Neurosciences, 35, 335-344. doi:10.1016/ j.tins.2012.03.005