Ventrolateral Motor Thalamus Abnormal Connectivity in Essential Tremor Before and After Thalamotomy: A Resting-State Functional Magnetic Resonance Imaging Study

Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor

“…Resting-state functional MRI (rs-fMRI) is a suitable neuroimaging modality for the evaluation of many neurological and psychiatric diseases (Barkhof, Haller, & Rombouts, 2014;Hacker, Perlmutter, Criswell, Ances, & Snyder, 2012). To date, only a few studies have explored connectivity alterations in ET, and those that did were mainly focused on the cerebello-thalamo-cortical network, which is mainly related to motor symptoms (Buijink et al, 2015;Caligiuri et al, 2017;Mueller et al, 2017), or on the study of surgical therapeutic applications (Akram et al, 2018;Tuleasca et al, 2018). In a recent study, ET patients showed increased connectivity in resting-state networks involved in cognitive processes and decreased connectivity in the cerebellum and visual networks (Benito-León et al, 2015).…”

Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor

“…We have systematically computed Power's framewise displacement index for each time point (Power, Barnes, Snyder, Schlaggar, & Petersen, 2012) in all our patients and had to exclude several of them from our perspective clinical and neuroimaging protocol, so as to avoid obtaining spurious correlations which could have potentially appeared after our analysis, in the absence of such caution. In fact, our rs-fMRI data consisted of 300 volumes of a repeated gradient echo-planar imaging T2*-weighted sequence (as opposed to only 120 in the study of Benito-Léon and coauthors) and we reported that pretherapeutically, the mean number of frames taken out was 35 (median 15, range 0-135), and at 1 year after thalamotomy, was also 35 (median 15, range 0-150) (Tuleasca, Najdenovska, Regis, et al, 2018d). Here (Benito-Leon et al, 2019), although the authors report that data points associated with too large instantaneous motion were not included in their analyses (through the use of dedicated scrubbing repressors as covariates), there is no mention of the framewise displacement threshold that was used in doing so.…”

Letter to the Editor. Resting-state functional MRI for functional neurosurgery: seeing the light?

“…Boerwinkle et al 1 have recently suggested that using rs-fMRI might improve outcomes using MRI-guided stereotactic laser ablation for hypothalamic hamartomas. We have demonstrated before how stereotactic radiosurgical thalamotomy for drug-resistant essential tremor (ET) correlates with changes within large-scale brain networks ( Figure 1) [6][7][8][9][10] . Comparison of pre-and post-inventional imaging allowed confirming the role of the ventrointermediate nucleus target region in the tremor network 7,8 .…”