What is it about?

This commentary addresses and challenges a concept that is commonly asserted in functional brain imaging studies of children as compared with adults: That patterns of activity for the same tasks develop from "diffuse"to "focal" with increasing age. We argue here that some articulations of this idea are in conflict with what is already established about the realization of the cortex, as well as being ill-defined and only qualitatively assessed.

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Why is it important?

In this article, we articulate some of the pitfalls of doing qualitative, side-by-side image inspections of two groups and describing their apparent differences without appropriately and rigorously testing them using direct statistical comparison mapping. This is important because a majority of early fMRI studies of children claim that the organization developed from "diffuse to focal" and we argue that there is actually no strong basis for this assertion. Instead, based on rigorous analysis, we propose that a larger number of brain regions are involved at younger ages without having to invoke the ill-defined concept of "diffuse."


The concept challenged in this paper is still alive and well, commonly asserted even almost 20 years after our publication, despite the case we made for greater rigor and precision. We still hope these points will find increasing acceptance and awareness in the field.

Dr. Tim T. Brown
University of California at San Diego, School of Medicine

Read the Original

This page is a summary of: Does human functional brain organization shift from diffuse to focal with development?, Developmental Science, January 2006, Wiley,
DOI: 10.1111/j.1467-7687.2005.00455.x.
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