Multifractal Analysis of Attentional Modulation in Macaque Area V4 Using Optical Imaging

Akshay, E (2017) Multifractal Analysis of Attentional Modulation in Macaque Area V4 Using Optical Imaging. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Akshay E (12MS035)) 12MS035.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

In primates (both human and non-human),much of brain volume (upto 80%) is occupied by connections between different parts of the cerebral cortex. Specificity of these connections forms information processing networks that are critical to normal sensory, motor, and cognitive function. Primate brain neocortex is organized into repeating patterns of units called cortical columns.However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. As we lack the resolution to probe the columnar dynamics of Human brain using fMRI techniques, we start with a nonhuman primate using Intrinsic Signal Optical Imaging and try to understand how visual perception works in a monkey brain, following the monkey connectome proposal. Using novel techniques like Intrinsic Signal Optical Imaging we try to understand the intra-areal and inter-areal network patterns in the brain, and thereby decoding the network topology.This would give insights into how human brain works. We analyze the dynamics of different regions in V4 starting from domain level to a region with multiple domains using the optical imaging data obtained from Macaque monkey brain when it is involved in attentional modulation task using multifractal analysis and quantify the measure of correlations through Hurst exponent and singularity spectrum. One dimensionalMultifractal Detrended Fluctuation Analysis and two dimensional Multifractal Detrended Moving Average Analyzis have been used to extract the time evolution of correlations in the V4. It turns out that visual attentional modulation increases or decreases the correlations, depending on the region we are looking at in V4 which directly follows from the time series of Hurst exponent. Also, we could observe the long range correlations among the domains from the time series of higher order generalized Hurst exponents.

Actions (login required)

View Item