Excitability regulation in the dorsomedial prefrontal cortex during sustained instructed fear responses: a TMS-EEG study

AbstractThreat detection is essential for protecting individuals from adverse situations, in which a network of amygdala, limbic regions and dorsomedial prefrontal cortex (dmPFC) regions are involved in fear processing. Excitability regulation in the dmPFC might be crucial for fear processing, while abnormal patterns could lead to mental illness. Notwithstanding, non-invasive paradigms to measure excitability regulation during fear processing in humans are missing. To address this challenge we adapted an approach for excitability characterization, combining electroencephalography (EEG) and transcranial magnetic stimulation (TMS) over the dmPFC during an instructed fear paradigm, to dynamica…

Multifocal Repetitive Transcranial Magnetic Stimulation—A Novel Paradigm in Migraine Treatment

Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation method used for analyzing structural and functional interactions in brain, assess cortical reactivity, and map functionally relevant brain regions inducing a controlled current pulse in a defined region of the cortex. From a clinical point of view, TMS has shown promising results in the therapeutic approach in a large number of psychiatric and neurological conditions such as anxiety, depression, OCD, headache disorders—migraine being one of the most encountered, etc. In patients with migraine, the pharmacologic therapy can be divided in abortive and preventive treatment of the attack. Usually the treatment is starte…

Increased migraine-free intervals with multifocal repetitive transcranial magnetic stimulation.

Introduction: Episodic migraine is a debilitating condition associated with vast impairments of health, daily living, and life quality. Several prophylactic treatments exist, having a moderate ratio of action related to side effects and therapy costs. Repetitive transcranial magnetic stimulation (rTMS) is an evidence based therapy in several neuropsychiatric conditions, showing robust efficacy in alleviating specific symptoms. However, its efficacy in migraine disorders is unequivocal and might be tightly linked to the applied rTMS protocol. We hypothesized that multifocal rTMS paradigm could improve clinical outcomes in patients with episodic migraine by reducing the number of migraine day…

Community driven dynamics of oscillatory network responses to threat

AbstractPhysiological responses to threat stimuli involve neural synchronized oscillations in cerebral networks with distinct organization properties. Community architecture within these networks and its dynamic adaptation could play a critical role in achieving optimal physiological responses.Here we applied dynamic network analyses to address the early phases of threat processing at the millisecond level, describing multi-frequency (theta and alpha) integration and basic reorganization properties (flexibility and clustering) that drive physiological responses. We quantified cortical and subcortical network interactions and captured illustrative reconfigurations using community allegiance …

revised_supplementary_TAN-18-OR-0100 – Supplemental material for Structural brain network fingerprints of focal dystonia

Supplemental material, revised_supplementary_TAN-18-OR-0100 for Structural brain network fingerprints of focal dystonia by Venkata C. Chirumamilla, Christian Dresel, Nabin Koirala, Gabriel Gonzalez-Escamilla, Günther Deuschl, Kirsten E. Zeuner, Muthuraman Muthuraman and Sergiu Groppa in Therapeutic Advances in Neurological Disorders

Excitability regulation in the dorsomedial prefrontal cortex during sustained instructed fear responses: a TMS-EEG study

AbstractBackgroundThreat detection is essential for protecting individuals from precarious situations. Early studies suggested a network of amygdala, limbic regions and dorsomedial prefrontal cortex (dmPFC) involved in fear processing. Excitability regulation in the dmPFC might be crucial for physiological fear processing, while an abnormal excitability pattern could lead to mental illness. Non-invasive paradigms to measure excitability regulation during fear processing in humans are missing.MethodsWe adapted an experimental approach of excitability characterization using electroencephalography (EEG) recordings and transcranial magnetic stimulation (TMS) over the dmPFC during an instructed …

Structural brain network fingerprints of focal dystonia

Background: Focal dystonias are severe and disabling movement disorders of a still unclear origin. The structural brain networks associated with focal dystonia have not been well characterized. Here, we investigated structural brain network fingerprints in patients with blepharospasm (BSP) compared with those with hemifacial spasm (HFS), and healthy controls (HC). The patients were also examined following treatment with botulinum neurotoxin (BoNT). Methods: This study included matched groups of 13 BSP patients, 13 HFS patients, and 13 HC. We measured patients using structural-magnetic resonance imaging (MRI) at baseline and after one month BoNT treatment, at time points of maximal and minim…

Grey Matter Microstructural Integrity Alterations in Blepharospasm Are Partially Reversed by Botulinum Neurotoxin Therapy.

OBJECTIVE Benign Essential Blepharospasm (BEB) and hemifacial spasm (HFS) are the most common hyperkinetic movement disorders of facial muscles. Although similar in clinical presentation different pathophysiological mechanisms are assumed. Botulinum Neurotoxin (BoNT) is a standard evidence-based treatment for both conditions. In this study we aimed to assess grey matter microstructural differences between these two groups of patients and compared them with healthy controls. In patients we furthermore tracked the longitudinal morphometric changes associated with BoNT therapy. We hypothesized microstructural differences between the groups at the time point of maximum symptoms representation a…

Primary Sensorimotor Cortex Drives the Common Cortical Network for Gamma Synchronization in Voluntary Hand Movements

Background: Gamma synchronization (GS) may promote the processing between functionally related cortico-subcortical neural populations. Our aim was to identify the sources of GS and to analyze the direction of information flow in cerebral networks at the beginning of phasic movements, and during medium-strength isometric contraction of the hand. Methods: We measured 64-channel electroencephalography in 11 healthy volunteers (age: 25 ± 8 years; four females); surface electromyography detected the movements of the dominant hand. In Task 1, subjects kept a constant medium-strength contraction of the first dorsal interosseus muscle, and performed a superimposed repetitive voluntary self-paced br…

Combining transcranial magnetic stimulation and subdural electrodes for pain modulation

Establishing and validating a new source analysis method using phase.

Electroencephalogram (EEG) measures the brain oscillatory activity non-invasively. The localization of deep brain generators of the electric fields is essential for understanding neuronal function in healthy humans and for damasking specific regions that cause abnormal activity in patients with neurological disorders. The aim of this study was to test whether the phase estimation from scalp data can be reliably used to identify the number of dipoles in source analyses. The steps performed included: i) modeling different phasic oscillatory signals using auto-regressive processes at a particular frequency, ii) simulation of two different noises, namely white and colored noise, having differen…

Translation of Functional Domain Abnormalities from Human to Mouse Motor System

Functional connectivity analysis using whole brain and regional network metrics in MS patients

In the present study we investigated brain network connectivity differences between patients with relapsing-remitting multiple sclerosis (RRMS) and healthy controls (HC) as derived from functional resonance magnetic imaging (fMRI) using graph theory. Resting state fMRI data of 18 RRMS patients (12 female, mean age ± SD: 42 ± 12.06 years) and 25 HC (8 female, 29.2 ± 5.38 years) were analyzed. In order to obtain information of differences in entire brain network, we focused on both, local and global network connectivity parameters. And the regional connectivity differences were assessed using regional network parameters. RRMS patients presented a significant increase of modularity in comparis…

Supplementary_Figure_2 – Supplemental material for Structural brain network fingerprints of focal dystonia

Supplemental material, Supplementary_Figure_2 for Structural brain network fingerprints of focal dystonia by Venkata C. Chirumamilla, Christian Dresel, Nabin Koirala, Gabriel Gonzalez-Escamilla, Günther Deuschl, Kirsten E. Zeuner, Muthuraman Muthuraman and Sergiu Groppa in Therapeutic Advances in Neurological Disorders

sup1_inks_jpg – Supplemental material for Structural brain network fingerprints of focal dystonia

Supplemental material, sup1_inks_jpg for Structural brain network fingerprints of focal dystonia by Venkata C. Chirumamilla, Christian Dresel, Nabin Koirala, Gabriel Gonzalez-Escamilla, Günther Deuschl, Kirsten E. Zeuner, Muthuraman Muthuraman and Sergiu Groppa in Therapeutic Advances in Neurological Disorders

Supp1_jpg – Supplemental material for Structural brain network fingerprints of focal dystonia

Supplemental material, Supp1_jpg for Structural brain network fingerprints of focal dystonia by Venkata C. Chirumamilla, Christian Dresel, Nabin Koirala, Gabriel Gonzalez-Escamilla, Günther Deuschl, Kirsten E. Zeuner, Muthuraman Muthuraman and Sergiu Groppa in Therapeutic Advances in Neurological Disorders

Supp_figure_3_inkscape_png_jpg – Supplemental material for Structural brain network fingerprints of focal dystonia

Supplemental material, Supp_figure_3_inkscape_png_jpg for Structural brain network fingerprints of focal dystonia by Venkata C. Chirumamilla, Christian Dresel, Nabin Koirala, Gabriel Gonzalez-Escamilla, Günther Deuschl, Kirsten E. Zeuner, Muthuraman Muthuraman and Sergiu Groppa in Therapeutic Advances in Neurological Disorders