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Abstract:

The aim of this Research Topic was to show how broad the field of brain stimulation has become recently, including basic research and clinical application. Numerous brain stimulation methods are being investigated to serve as neuromodulatory techniques, treating a variety of neuropsychiatric or neurological disorders (Antal et al., 2022; Camacho-Conde et al., 2022; Siebner et al., 2022). They can be divided into noninvasive and invasive methods. Non-invasive brain stimulation includes transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), transcranial electrical stimulation (tES) and non-invasive vagus nerve stimulation (VNS). Invasive brain stimulation consists of intracortical microstimulation (ICMS) and deep brain stimulation (DBS)

Authors: Benali, Alia; Tsutsui, Ken-Ichiro Sekino, Masaki Pfeiffer, Friederike

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Book

Publisher: FRONTIERS EBOOK

Editor: Benali, A., Tsutsui, K-I., Sekino, M., Pfeiffer, F.

Month: Dec. 2022

ISBN: 978-2-83250-757-5

Authors: Ramachandra, Vishnudev Giese, Martin A.; Benali, Alia

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article

Abstract:

Transcranial magnetic stimulation (TMS), a non-invasive method for stimulating the brain, has been used for more than 35 years. Since then, there have been many human studies using sophisticated methods to infer how TMS interacts with the brain. However, these methods have their limitations, e.g. recording of EEG potentials, which are summation potentials from many cells and generated across many cortical layers, make it very difficult to localize the origin of the potentials and relate it to TMS induced effects. However, this is necessary to build accurate models that predict TMS action in the human brain. In recent years, we have developed a method that allows us to demonstrate nearly the direct effect of a TMS pulse at the cellular level. We transferred a TMS stimulation protocol from humans to a rat model. In this way, we were able to gain direct access to neurons activated by TMS, thereby reducing the parameter space by many factors. Our data show that a single TMS pulse affects cortical neurons for more than 300 ms. In addition to temporal dynamics, there are also spatial effects. These effects arise at both local and global scale after a single TMS pulse. The local effect occurs in the motor cortex and is very short-lived. It is characterized by a high-frequency neuronal discharge and is reminiscent of the I-wave patterns described in humans at the level of the spinal cord. The global effect occurs in many cortical and subcortical areas in both hemispheres and is characterized by an alternation of excitation and inhibition. Both effects either occur together or only the global effect is present. Next, we are planning to correlate these neurometric data with induced electric field modeling to create detailed TMS-triggered neuronal excitation models that could help us better understand cortical TMS interference.

Authors: Benali, Alia; Li, Bingshuo Ramachandra, Vishnudev Oeltermann, Axel Giese, Martin A.; Schwarz, Cornelius

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: In Collection

JRESEARCH_BOOK_TITLE: Brain Stimulation 14 (6)

Publisher: Elsevier

Month: Nov-Dec 2021

Pages: 1745

ISBN: 1935-861X

Abstract:

Originating in basic research, as a basis for understanding the function of brain areas, brain stimulation is currently employed for the treatment of many brain disorders including Parkinson's Disease, Epilepsy, and Depression. However, the available techniques for brain stimulation can differ, in the degree of surgical intervention: Invasive Brain Stimulation (IBS) techniques such as Deep Brain Stimulation (DBS) and Intracortical Microstimulation (ICMS) that require extensive surgical intervention for placement of electrodes, or Non-Invasive Brain Stimulation (NIBS) techniques, for example, Transcranial Magnetic Stimulation (TMS) and Transcranial Electrical Current Stimulation (tES) that require minimal or no intervention. With the development of thin movable electrodes having superior biocompatibility, some of the side effects related to the invasive procedure of IBS will very likely to be overcome. Likewise, advances in NIBS techniques related to spatial and temporal precision have closed the gap to its invasive counterparts. In parallel, considerable progress is being made in research laboratories using brain stimulation techniques to gain deeper insights into brain functions, and underlying neural and glial mechanisms, which in turn increase the efficacy of brain stimulation in treatments. Therefore, the therapeutic potential of stimulation techniques is not yet completed exhausted. However, the question remains, can the results from basic research be transferred easily to treatment of patients? By looking at the successes achieved in the past years, the answer to this question should be yes. Well-described animal models, good theoretical and anatomical models are essential for such translations. The proposed research topic aims to gather more evidence on the role of BS as a tool to better understand the physiological mechanisms of the brain, by studying the temporal and spatial dynamics of cortical and subcortical activations, and to discuss challenges and develop strategies for innovative therapeutic procedures. This Research Topic welcomes Original Research, Perspectives, Systematic Reviews, and Meta-Analyses covering the following topics: - Basic research models, theoretical models, preclinical or clinical applications of cortical and subcortical stimulation using TMS, tES, ICMS, and DBS in animal models and humans - Translational articles dealing with the effects of neuromodulation on the biochemistry of brain tissues, as well as those focusing on modeling strategies and closed-loop technologies - Neurophysiological studies in animal models and humans focusing on the mechanisms leading to altered cortical excitability, plasticity, and connectivity, or new experimental models aimed at understanding changes in cellular processes induced by electrical or inductive stimulation of neurons.

Authors: Benali, Alia; Pfeiffer, Friederike Tsutsui, Ken-Ichiro

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article

Abstract:

Originating in basic research, as a basis for understanding the function of brain areas, brain stimulation is currently employed for the treatment of many brain disorders including Parkinson's Disease, Epilepsy, and Depression. However, the available techniques for brain stimulation can differ, in the degree of surgical intervention: Invasive Brain Stimulation (IBS) techniques such as Deep Brain Stimulation (DBS) and Intracortical Microstimulation (ICMS) that require extensive surgical intervention for placement of electrodes, or Non-Invasive Brain Stimulation (NIBS) techniques, for example, Transcranial Magnetic Stimulation (TMS) and Transcranial Electrical Current Stimulation (tES) that require minimal or no intervention. With the development of thin movable electrodes having superior biocompatibility, some of the side effects related to the invasive procedure of IBS will very likely to be overcome. Likewise, advances in NIBS techniques related to spatial and temporal precision have closed the gap to its invasive counterparts. In parallel, considerable progress is being made in research laboratories using brain stimulation techniques to gain deeper insights into brain functions, and underlying neural and glial mechanisms, which in turn increase the efficacy of brain stimulation in treatments. Therefore, the therapeutic potential of stimulation techniques is not yet completed exhausted. However, the question remains, can the results from basic research be transferred easily to treatment of patients? By looking at the successes achieved in the past years, the answer to this question should be yes. Well-described animal models, good theoretical and anatomical models are essential for such translations. The proposed research topic aims to gather more evidence on the role of BS as a tool to better understand the physiological mechanisms of the brain, by studying the temporal and spatial dynamics of cortical and subcortical activations, and to discuss challenges and develop strategies for innovative therapeutic procedures. This Research Topic welcomes Original Research, Perspectives, Systematic Reviews, and Meta-Analyses covering the following topics: - Basic research models, theoretical models, preclinical or clinical applications of cortical and subcortical stimulation using TMS, tES, ICMS, and DBS in animal models and humans - Translational articles dealing with the effects of neuromodulation on the biochemistry of brain tissues, as well as those focusing on modeling strategies and closed-loop technologies - Neurophysiological studies in animal models and humans focusing on the mechanisms leading to altered cortical excitability, plasticity, and connectivity, or new experimental models aimed at understanding changes in cellular processes induced by electrical or inductive stimulation of neurons.

Authors: Benali, Alia; Tsutsui, Ken-Ichiro Pfeiffer, F. Sekino, Masaki

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Electronic Article

Journal: Frontiers in Human Neuroscience Brain Imaging and Stimulation

Abstract:

Fast and efficient transmission of electrical signals in the nervous system is mediated through myelinated nerve fibers. In neuronal diseases such as multiple sclerosis, the conduction properties of axons are disturbed by the removal of the myelin sheath, leaving nerve cells at a higher risk of degenerating. In some cases, the protective myelin sheath of axons can be rebuilt by remyelination through oligodendroglial cells. In any case, however, changes in the ion channel organization occur and may help to restore impulse conduction after demyelination. On the other hand, changes in ion channel distribution may increase the energy demand of axons, thereby increasing the probability of axonal degeneration. Many attempts have been made or discussed in recent years to increase remyelination of affected axons in demyelinating diseases such as multiple sclerosis. These approaches range from pharmacological treatments that reduce inflammatory processes or block ion channels to the modulation of neuronal activity through electrical cortical stimulation. However, these treatments either affect the entire organism (pharmacological) or exert a very local effect (electrodes). Current results show that neuronal activity is a strong regulator of oligodendroglial development. To bridge the gap between global and very local treatments, non-invasive transcranial magnetic stimulation could be considered. Transcranial magnetic stimulation is externally applied to brain areas and experiments with repetitive transcranial magnetic stimulation show that the neuronal activity can be modulated depending on the stimulation parameters in both humans and animals. In this review, we discuss the possibilities of influencing ion channel distribution and increasing neuronal activity by transcranial magnetic stimulation as well as the effect of this modulation on oligodendroglial cells and their capacity to remyelinate previously demyelinated axons. Although the physiological mechanisms underlying the effects of transcranial magnetic stimulation clearly need further investigations, repetitive transcranial magnetic stimulation may be a promising approach for non-invasive neuronal modulation aiming at enhancing remyelination and thus reducing neurodegeneration

Authors: Pfeiffer, F. Benali, Alia

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article

Abstract:

There is increasing evidence from genetic, biochemical, pharmacological, neuroimaging and post-mortem studies that immunological dysregulation plays a crucial role in the pathogenesis of psychoses. The involvement of microglia in schizophrenia and bipolar disorder (BD) has remained controversial, however, since results from various post-mortem studies are still inconclusive. Here, we analyzed the estimated density of microglia of age-matched individuals with schizophrenia (n=17), BD (n=13), and non-psychiatric control subjects (n=17) in the anterior midcingulate cortex (aMCC), a brain area putatively involved in the pathogenesis of psychoses, using ionized calcium binding adaptor molecule 1 (Iba1)—immunohistochemistry. The microglial cells displayed a homogenously distributed Iba1—staining pattern in the aMCC with slightly varying activation states in all three groups. The estimated microglial densities did not difer signifcantly between individuals with schizophrenia, BD and control subjects. Remarkably, when both hemispheres were investigated separately within the three groups, the density was signifcantly lateralized towards the right aMCC in schizophrenia (p=0.01) and—even more evident—in BD subjects (p=0.008). This left–right lateralization was not observed in the control group (p=0.52). Of note, microglial density was signifcantly lower in BD individuals who did not commit suicide compared with BD individuals who died from suicide (p=0.002). This diference was not observed between individuals with BD who committed suicide and controls. The results, tentatively interpreted, suggest a hitherto unknown increased lateralization of microglial density to the right hemisphere in both psychiatric groups. If confrmed in independent samples, lateralization should be considered in all post-mortem studies on microglia. Density diferences between suicide and non-suicide individuals needs further elucidation.

Authors: Petrasch-Parwez, E. Schöbel, A. Benali, Alia; Moinfar, Z. Förster, E. Br\"une, M. Juckel, G.

Research Areas: Uncategorized

Type of Publication: Article

Authors: Li, Bin Virtanen, Jan Paul Oeltermann, Anton Schwarz, Con Giese, Martin A.; Ziemann, U Benali, Alia

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article

Authors: Benali, Alia; Trippe, J Weiler, E. Mix, A Petrasch-Parwez, E Girzalsky, W Eysel, U. T Erdmann, R Funke, K.

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article

Authors: Benali, Alia; Weiler, E Benali, Y Dinse, H. R Eysel, U. T

Research Areas: Neurophysiology and Brainstimulation

Type of Publication: Article