Community structure in networks of functional connectivity: resolving functional organization in the rat brain with pharmacological MRI.

Full Abstract

In the study of functional connectivity, fMRI data can be represented mathematically as a network of nodes and links, where image voxels represent the nodes and the connections between them reflect a degree of correlation or similarity in their response. Here we show that, within this framework, functional imaging data can be partitioned into 'communities' of tightly interconnected voxels corresponding to maximum modularity within the overall network. We evaluated this approach systematically in application to networks constructed from pharmacological MRI (phMRI) of the rat brain in response to acute challenge with three different compounds with distinct mechanisms of action (d-amphetamine, fluoxetine, and nicotine) as well as vehicle (physiological saline). This approach resulted in bilaterally symmetric sub-networks corresponding to meaningful anatomical and functional connectivity pathways consistent with the purported mechanism of action of each drug. Interestingly, common features across all three networks revealed two groups of tightly coupled brain structures that responded as functional units independent of the specific neurotransmitter systems stimulated by the drug challenge, including a network involving the prefrontal cortex and sub-cortical regions extending from the striatum to the amygdala. This finding suggests that each of these networks includes general underlying features of the functional organization of the rat brain.

Author information

Author/s: Schwarz, Adam J (AJ); Gozzi, Alessandro (A); Bifone, Angelo (A);

Affiliation: Neurosciences Centre of Excellence in Drug Discovery, GlaxoSmithKline S.p.A., Via Fleming 4, 37135 Verona, Italy.

Journal and publication information

Publication Type: Journal Article

Journal: NeuroImage (Neuroimage), published in United States. (Language: eng)

Reference: 2009-Aug; vol 47 (issue 1) : pp 302-11

Dates: Created 2009/06/01; Completed 2009/08/24;

PMID: 19345737, status: MEDLINE (last retrieval date: 8/24/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Algorithms
Animals
Brain - anatomy & histology; drug effects; physiology
Brain Mapping
Dextroamphetamine - pharmacology
Dopamine Uptake Inhibitors - pharmacology
Fluoxetine - pharmacology
Magnetic Resonance Imaging - methods

Magnetic Resonance Imaging - methods
Male
Neural Pathways - anatomy & histology; drug effects; physiology
Nicotine - pharmacology
Nicotinic Agonists - pharmacology
Rats
Rats, Sprague-Dawley
Serotonin Uptake Inhibitors - pharmacology

Associated Chemicals: Dopamine Uptake Inhibitors (0) ; Nicotinic Agonists (0) ; Serotonin Uptake Inhibitors (0) ; Dextroamphetamine (51-64-9) ; Nicotine (54-11-5) ; Fluoxetine (54910-89-3)

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