Title
The multiscale character of evoked cortical activity.
Abstract
Both the architecture and the dynamics of the brain have characteristic features at different spatial scales. However, the existence, nature and function of dynamical interdependencies between such scales have not been investigated. We studied the multiscale properties of functional magnetic resonance imaging (fMRI) data acquired while human subjects viewed a visual image. Traditional “region of interest” analysis of this data set revealed evoked activity in primary and extrastriate visual cortex. Wavelet transform in the spatial domain provides a multiscale representation of this evoked brain activity. Studying the correlation structure of this representation revealed strong and novel interdependencies in these data within and between different spatial scales. We found that such correlations are stronger than those evident in the original data and comparable in magnitude to those obtained after Gaussian smoothing. However, analysis of the data in the wavelet domain revealed additional structure such as positive correlations, strong anti-correlations and phase-lagged interdependencies. Statistical significance of these effects was inferred through nonparametric bootstrap techniques. We conclude that the spatial analysis of functional neuroimaging data in the wavelet domain provides novel information which may reflect complex spatiotemporal neuronal activity and information encoding. It also affords a quantitative means of testing hierarchical and multiscale models of cortical activity.
Year
DOI
Venue
2006
10.1016/j.neuroimage.2005.10.041
NeuroImage
Keywords
Field
DocType
Functional connectivity,Neural dynamics,Wavelet analysis,Neurovascular coupling,Complexity
Functional neuroimaging,Cognitive psychology,Brain activity and meditation,Artificial intelligence,Wavelet,Wavelet transform,Computer vision,Visual cortex,Functional magnetic resonance imaging,Pattern recognition,Gaussian blur,Region of interest,Mathematics
Journal
Volume
Issue
ISSN
30
4
1053-8119
Citations 
PageRank 
References 
6
0.67
13
Authors
5
Name
Order
Citations
PageRank
Michael Breakspear180754.18
Ed Bullmore21331150.94
Kevin Aquino3534.08
Pritha Das49615.52
Leanne M Williams57411.81