Boon, Paul

Christiaen, Emma

Descamps, Benedicte

Goossens, Marie-Gabrielle

Raedt, Robrecht

Vanhove, Christian

Ghent University Academic Bibliography

Functional connectivity changes during epileptogenesis:  a longitudinal resting-state functional MRI study Emma Christiaen1, Marie-Gabrielle Goossens2, Benedicte Descamps1, Paul Boon2, Robrecht Raedt2, Christian Vanhove1 1MEDISIP, Department of Electronics and Information Systems, Ghent University, Belgium 2Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology (LCEN3), Department of Neurology, Ghent University, Belgium  Purpose Research has shown that abnormal functional brain networks could be involved in the development of temporal lobe epilepsy (TLE). Gaining more insight into these networks can be useful for the development of new therapies. We aim to map changes in functional networks during epileptogenesis in the intraperitoneal kainic acid (IPKA) rat model for TLE using longitudinal resting-state functional magnetic resonance imaging (rsfMRI) and graph theory. Method Twenty-four adult male Sprague-Dawley rats (276±15g) were used. Seventeen animals were intraperitoneally injected with kainic acid according to the protocol of Hellier et al. (Epilepsy Res. 1998;31:73–84.) resulting in status epilepticus (SE). The other seven animals were used as a healthy control group. RsfMRI was acquired before and at five timepoints during the development of epilepsy. After pre-processing, the Pearson correlation coefficient was calculated between the fMRI time series of 38 regions of interest (ROIs) and stored in a correlation matrix. Several network measures, including clustering coefficient and characteristic path length, were calculated using a graph theoretical network analysis toolbox (GRETNA). Results In the IPKA model the mean correlation coefficients significantly decrease from 0.74±0.09 to 0.56±0.11 during epileptogenesis (t(702)=110.62, p<0.001), indicating that network connections progressively become weaker. The median clustering coefficient decreases from 0.45 (IQR=0.46-0.44) to 0.36 (IQR=0.40-0.33) during epileptogenesis, indicating a decrease in segregation or local interconnectivity in the functional brain network. The median characteristic path length increases from 1.76 (IQR=1.91-1.61) to 2.38 (IQR=2.60-2.06), indicating a decrease in integration or overall communication efficiency. A Wilcoxon Signed-Rank Test showed that the decrease in clustering coefficient and increase in characteristic path length are statistically significant, Z=3.62, p<0.001 and Z=-3.38, p<0.001 respectively. Conclusion The results of this study show that the connections in the functional brain network progressively become weaker and that segregation and integration of the network are decreased during epileptogenesis.   

Functional connectivity changes during epileptogenesis : a longitudinal resting-state functional MRI study

https://biblio.ugent.be/publication/8617993/file/8617994

Functional connectivity changes during epileptogenesis : a longitudinal resting-state functional MRI study

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Ghent University Academic Bibliography