Epilepsy Research (2012) 99, 327—334 jou rn al h om epa ge: www.elsevier.com/locate/epilepsyres Cortical and thalamic resting-state functional connectivity is altered in childhood absence epilepsy Richard A. Masterton a , Patrick W. Carney a,b , Graeme D. Jackson a,b,* a Brain Research Institute, Florey Neuroscience Institutes, Heidelberg, Victoria, Australia b The University of Melbourne, Department of Medicine (Austin Health), Heidelberg, Victoria, Australia Received 6 September 2011; received in revised form 14 December 2011; accepted 20 December 2011 Available online 24 January 2012 KEYWORDS Absence; fMRI; Functional connectivity Summary Purpose: Functional imaging studies have identified a common network of brain regions that activate and deactivate during the generalised spike wave (GSW) discharges of childhood absence epilepsy (CAE). Functional connectivity within this network is also altered during the resting state. In this study our aim was to assess functional connectivity throughout the whole brain of patients with CAE. Methods: We studied a group of eleven patients with untreated CAE and eleven matched controls using resting-state fMRI. We measured functional connectivity between every pair of voxels and generated images of ‘‘whole-brain’’ functional connectivity by counting the number of functional connections of each voxel. Key findings: There were marked differences between CAE patients and controls in whole brain functional connectivity. The patients had decreased connectivity in the thalamus and basal ganglia and increased connectivity in the medial occipital cortex. Significance: These findings suggest enduring changes in function of the thalamus and the cortex in CAE patients even when there is no GSW activity. These human functional connectivity data support the findings in animal models of involvement of cortex as well as thalamus in absence epilepsy. © 2012 Elsevier B.V. All rights reserved. Introduction Genetic (previously idiopathic) generalised epilepsy (GGE) (Berg et al., 2010) is characterised by episodic brain dysfunction involving widespread hypersynchronous activity ∗ Corresponding author at: Melbourne Brain Centre, 245 Burgundy Street, Heidelberg, Victoria 3084, Australia. Tel.: +61 3 9035 7068. E-mail address: bri@brain.org.au (G.D. Jackson). appearing as generalised spike wave (GSW) discharges on the EEG (Blumenfeld, 2005). The network of brain regions that are active at the time of these events has been defined using simultaneous EEG and functional magnetic resonance imaging (EEG-fMRI) (Archer et al., 2003; Gotman et al., 2005; Hamandi et al., 2006; Moeller et al., 2008; Carney et al., 2010; Bai et al., 2010). These studies have shown relative increases in the thalamus and decreases in the ‘‘default-mode’’ cortical regions, the caudate nucleus and brainstem (herein referred to as the ‘‘GSW network’’). In 0920-1211/$ — see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.eplepsyres.2011.12.014