ABSTRACT
BACKGROUND: Most repetitive transcranial magnetic stimulation (rTMS) studies aiming to reduce auditory verbal hallucinations (AVH) in schizophrenia target the left temporo-parietal junction (TPJ), but the efficacy of this approach remains controversial. The observed differences in efficacy could be attributed to inaccurate target localization. Here, to precisely quantify anatomical bias induced by localization method, we developed a free open-source software (GeodesicSlicer) that computes shortest curved path (i.e. geodesic) between rTMS targets. Here we compare a personalized target with accurate anatomical criteria with a standardized target based on the 10-20 EEG system (the middle between T3 and P3 electrodes: T3P3). METHODS: We compare in 69 patients with schizophrenia the geodesic distances of two approaches for rTMS target localization within the left TPJ. In addition, we characterize the personalized target according to the 10-20 EEG system. RESULTS: A differential of 3 cm in term of geodesic distance between rTMS localization approaches was observed. Moreover, this personalized target to treat AVH is located at 25% in the T3-P3 axis. CONCLUSIONS: This software for rTMS localization comparison demonstrates the difference between standardized and personalized rTMS target. This difference has the potential to explain a part of the dissonant clinical results found in previous rTMS studies.
Subject(s)
Schizophrenia , Brain , Hallucinations/etiology , Hallucinations/therapy , Humans , Schizophrenia/complications , Schizophrenia/therapy , Transcranial Magnetic Stimulation , Treatment OutcomeABSTRACT
NonInvasive Brain Stimulation (NIBS) is a potential therapeutic tool with growing interest, but neuronavigation-guided software and tools available for the target determination are mostly either expensive or closed proprietary applications. To address these limitations, we propose GeodesicSlicer, a customizable, free, and open-source NIBS therapy research toolkit. GeodesicSlicer is implemented as an extension for the widely used 3D Slicer medical image visualization and analysis application platform. GeodesicSlicer uses cortical stimulation target from either functional or anatomical images to provide functionality specifically designed for NIBS therapy research. The provided algorithms are tested and they are accessible through a convenient graphical user interface. Modules have been created for NIBS target determination according to the position of the electrodes in the 10-20 system electroencephalogram and calculating correction factors to adjust the repetitive Transcranial Magnetic Stimulation (rTMS) dose for the treatment. Two illustrative examples are processing with the module. This new open-source software has been developed for NIBS therapy: GeodesicSlicer is an alternative for laboratories that do not have access to neuronavigation system. The triangulation-based MRI-guided method presented here provides a reproducible and inexpensive way to position the TMS coil that may be used without the use of a neuronavigation system.
Subject(s)
Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Neuronavigation/methods , Software , Transcranial Magnetic Stimulation/methods , Adult , Algorithms , Brain/physiology , Depressive Disorder, Major/therapy , Electroencephalography/methods , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Schizophrenia/therapyABSTRACT
Neuroimaging studies have revealed brain regions involved in social cognition, which reportedly show functional alterations in schizophrenia. However, the social neural network has not been investigated with regards to language perception and social interactions in daily life. Here we developed and validated an integrative fMRI task to explore the neural basis of social cognition with regards to language perception in schizophrenia. The task comprised listening to film extracts and inferring mental states to characters. We first identified the functional network activated during the task in 28 healthy controls (HC). Next, we evaluated the reproducibility of Blood-Oxygen-Level Dependent (BOLD) variations in 14 HC participants. Finally, we investigated network impairment in 20 patients with schizophrenia (SZ) compared to HC. The HC group exhibited bilateral activation in the superior and middle temporal gyri (including the poles and the temporo-parietal junction). Overall, our novel integrative task induced activation of a functional network with good reproducibility and involved in language conveying social information. Compared to the HC group, the SZ group showed decreased recruitment of the right temporo-parietal junction. These findings may be useful for testing the impact of remediation on the brain, particularly on the network of language conveying social information.
Subject(s)
Brain/diagnostic imaging , Brain/physiology , Cognition/physiology , Magnetic Resonance Imaging/standards , Schizophrenia/diagnostic imaging , Social Behavior , Adult , Brain Mapping/methods , Brain Mapping/standards , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Reproducibility of Results , Schizophrenic Psychology , Temporal Lobe/diagnostic imagingABSTRACT
This exploratory study investigated the functional connectivity (FC) in the language network in schizophrenia patients (SZ) with auditory verbal hallucinations (AVHs), and the therapeutic efficacy of rTMS on it. Eleven SZ with AVHs and 10 healthy controls (HC) underwent two fMRI sessions using a speech listening paradigm. SZ received 20Hz rTMS following the first fMRI session. Compared to HC, SZ showed a reduced FC in the language network. While AVHs improved after 12days, no changes in FC were observed. This suggests the efficacy of high-frequency rTMS on AVH without any impact for rTMS on FC within the language network.
