This week's Biostatistics Seminar will feature Hongyu Zhao, PhD, Professor of Public Health (Biostatistics), of Genetics and of Statistics, Yale School of Public Health, talking on "Spatial Temporal Modeling of Gene Expression Dynamics During Brain Development".
Human neurodevelopment is a highly regulated biological process, and recent technological advances allow scientists to study the dynamic changes of neurodevelopment at the molecular level through the analysis of gene expression data from human brains. In this talk, we will focus on the analysis of data sampled from 16 brain regions in 15 time periods of neurodevelopment. We will introduce a two-step statistical inferential procedure to identify expressed and unexpressed genes and to detect differentially expressed genes between adjacent time periods. Markov Random Field (MRF) models are used to efficiently utilize the information embedded in brain region similarity and temporal dependency in our approach. We develop and implement a Monte Carlo expectation-maximization (MCEM) algorithm to estimate the model parameters. Simulation studies suggest that our approach achieves lower misclassification error and potential gain in power compared with models not incorporating spatial similarity and temporal dependency. We will also describe our methods to infer dynamic co-expression networks, spatial patterns, and ordered regulations across brain regions from these data. This is joint work with Zhixiang Lin, Ying Zhu, Can Yang, and Nenad Sestan.