h i g h l i g h t s • Modified chronic implantation of EEG electrodes and MRI-coil for rats. • Improved data consistency across imaging and video-EEG monitoring sessions. • Method allowing follow-up studies using simultaneous EEG-fMRI. • Network connectivity changes during epileptogenesis. a b s t r a c t Background: Simultaneous EEG-fMRI is a valuable tool in the clinic as it provides excellent temporal and spatial information about normal and diseased brain function. In pre-clinical research

more »

... ith small rodents, obtaining simultaneous EEG-fMRI in longitudinal studies faces a number of challenges, including issues related to magnetic susceptibility artifacts. New method: Here, we demonstrate a method for permanent MRI RF-coil and EEG electrode implantation in rats that is suitable for long-term chronic follow-up studies in both stimulus and resting-state fMRI paradigms. Results: Our findings showed that the screw-free implantation method is well suited for long-term followup studies in both freely moving video-EEG settings and fMRI without causing MRI susceptibility artifacts. Furthermore, the results demonstrated that a multimodal approach can be used to track the progression of structural and functional changes. Comparison with existing methods: The quality of both MRI and EEG data were comparable to those obtained with traditional methods with the benefit of combining them into artifact-free simultaneous recordings. The signal-to-noise ratios of the MRI images obtained with the implanted RF-coil were similar to those using a quadrature coil and were therefore suitable for resting-state fMRI experiments. Similarly, EEG data collected with the RF-coil/electrode set-up were comparable to EEG recorded with traditional epidural screw electrodes. Conclusion: This new multimodal EEG-fMRI approach provides a novel tool for concomitant analysis and follow-up of anatomic and functional MRI, as well as electrographic changes in a preclinical research.