Research Abstracts Online
January - December 2011
University of Minnesota Twin Cities
PI: Pavlos Gourtzelidis
Mental Maze Solving: A Study of the Visuospatial Processes in the Human Brain Using Functional Magnetic Resonance Imaging
Previous studies have investigated the processes that take place in the nervous system during visuospatial tasks using maze solving as a paradigm. Specifically, psychophysical experiments in humans and primates have shown that mental transversing of the maze path occurs when subjects are required to find the exit of a maze displayed on a computer screen. Neural recordings from the parietal lobes of monkeys have shown that neural activity during this task is related to various features of the maze. A commonly used estimation method, termed the population vector, uses neural activity to predict the direction of the maze that the monkey is tracing.
In this research, functional Magnetic Resonance Imaging (fMRI) is used to record the brain activity of healthy human subjects during maze solving. Preliminary results have shown that this activity correlates with this task, similar to the findings in other primates. The current analysis extends these results by studying the interactions of the activities in volumetric pixels (voxels) recorded in the brain. Specifically, the fMRI signal from each voxel will be prewhitened using an ARIMA model to avoid spurious results. The prewhitened time series will be cross-correlated to discover patterns of significant functional connectivities. The significant connections will then be used to define the edges of a network within the brain, while the voxels will be its vertices. Various measures of this network, such as the degree of each vertex, the centrality, and others will be analyzed in relation to the experimental covariates.