Stimulus Feature Selectivity of Clonally Related Neurons in the Primary Visual Cortex
Graduate Student, Neuroscience, Baylor College of Medicine (Mentors: Andreas Tolias & Wei Ji Ma)
The neocortex carries out complex mental functions such as perception and cognition. Despite major advances in understanding the properties of single neurons we still do not understand how the billions of neurons in the cortex orchestrate their activities together to perform these mental tasks. Recent studies suggest that cell lineage influences the connectivity and the functional properties of pyramidal cells in the neocortex. Neurons derived from the same progenitor are more likely to be synaptically connected and, in primary visual cortex, have similar tuning preferences compared to nearby, unrelated cells. However the magnitude of the effect differs dramatically between studies. In this talk I will describe our recent experiments using a novel method for lineage tracing to better understand the role of lineage in determining functional properties of neurons. These experiments will shed light on how functional networks are established during development and could provide a circuit level foundation to study neurodevelopmental disorders such as autism and schizophrenia.
Computational Studies on Ras Nanoclustering in Membrane Domains
Zhenlong Li, PhD
Postdoctoral Fellow, Integrative Biology & Pharmacology, University of Texas Medical School
Ras proteins are small GTP-hydrolyzing enzymes that operate as molecular switches in signal transduction pathways and present in a mutant, activated state in many human tumors. It has been shown that the lipid-modified C-terminus drive lateral segregation of Ras proteins into membrane sub-structures. Formation of such transient molecular assemblies, so-called nanoclusters, is emerging as a crucial mechanism for cells to achieve high-fidelity signal transmission. However, little is known about the molecular-level organization and physical driving forces underlying such Ras-membrane signalling platform. In this talk, I will discuss our recent computational studies on the lateral segregation of Ras C-terminus in a heterogeneous membrane environment. The membrane shape and energetic change associated with Ras nanoclustering will be highlighted to elucidate the molecular basis of nanocluster formation.