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A frontal-vagal network theory for Major Depressive Disorder: Implications for optimizing neuromodulation techniques
Major Depressive Disorder (MDD) is a psychiatric disorder characterized by high comorbidity with cardiovascular disease. Furthermore, a combination of high heart rate (HR) and low heart rate variability (HRV) has been frequently reported in depressed patients. The present review proposes a frontal-vagal (brain-heart) network that overlaps with functional nodes of the depression network. Moreover, we summarize neuromodulation studies that have targeted key nodes in this depression network, with subsequent impact on heart rate (HR) or heart-rate-variability (HRV), such as the dorsolateral prefrontal cortex (DLPFC), subgenual anterior cingulate cortex (sgACC), and the vagus nerve (VN).Safety of transcranial focused ultrasound stimulation: A systematic review of the state of knowledge from both human and animal studies
Low-intensity transcranial focused ultrasound stimulation (TFUS) holds great promise as a highly focal technique for transcranial stimulation even for deep brain areas. Yet, knowledge about the safety of this novel technique is still limited.Effects of single-session versus multi-session non-invasive brain stimulation on craving and consumption in individuals with drug addiction, eating disorders or obesity: A meta-analysis
Brain stimulation interventions are increasingly used to reduce craving and consumption in individuals with drug addiction or excessive eating behavior. However, the efficacy of these novel treatments and whether effect sizes are affected by the length of the intervention has not been comprehensively evaluated.A systematic review and meta-analysis of the effects of transcranial direct current stimulation (tDCS) on episodic memory
In the past decade, several studies have examined the effects of transcranial direct current stimulation (tDCS) on long-term episodic memory formation and retrieval. These studies yielded conflicting results, likely due to differences in stimulation parameters, experimental design and outcome measures.Can transcranial electric stimulation with multiple electrodes reach deep targets?
To reach a deep target in the brain with transcranial electric stimulation (TES), currents have to pass also through the cortical surface. Thus, it is generally thought that TES cannot achieve focal deep brain stimulation. Recent efforts with interfering waveforms and pulsed stimulation have argued that one can achieve deeper or more intense stimulation in the brain. Here we argue that conventional transcranial stimulation with multiple current sources is just as effective as these new approaches.Effects of cerebellar neuromodulation in movement disorders: A systematic review
The cerebellum is involved in the pathophysiology of many movement disorders and its importance in the field of neuromodulation is growing.TMS measures of motor cortex function after stroke: A meta-analysis
Transcranial magnetic stimulation (TMS) is commonly used to measure the effects of stroke on corticomotor excitability, intracortical function, and interhemispheric interactions. The interhemispheric inhibition model posits that recovery of motor function after stroke is linked to rebalancing of asymmetric interhemispheric inhibition and corticomotor excitability. This model forms the rationale for using neuromodulation techniques to suppress unaffected motor cortex excitability, and facilitate affected motor cortex excitability.Non-Invasive Brain Stimulation Improves Paretic Limb Force Production: A Systematic Review and Meta-Analysis
Hemiparesis is a common motor deficit post stroke. The affected side of the upper and lower extremities interferes with both unilateral and bilateral movements [1,2]. Typically, an inability to generate and modulate force production in paretic limbs causes movement control impairments such as compromised motor coordination, excessive movement variability, and motor dysfunctions evaluated by clinical assessments [3–5]. After experiencing a stroke, patients frequently show less magnitude of force production when executing actions on their paretic limb in comparison to their non-paretic limbs [6,7].A Systematic Review on the Acceptability and Tolerability of Transcranial Direct Current Stimulation Treatment in Neuropsychiatry Trials
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique based on the application of a weak, direct electric current over the scalp, thereby modifying brain activity and inducing neuroplasticity according to the montage of the apparatus and stimulation parameters [1]. This method has been increasingly used in the treatment of several psychiatric and neurologic disorders [2] as it presents appealing characteristics for use in clinical practice, such as ease of use, portability and low cost.A Systematic Review and Meta-Analysis of the Effects of Transcranial Direct Current Stimulation (tDCS) Over the Dorsolateral Prefrontal Cortex in Healthy and Neuropsychiatric Samples: Influence of Stimulation Parameters
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation (NIBS) technique that modulates spontaneous cortical activity using a low-intensity direct current (e.g. 1–2 mA) [1]. First studies evaluated tDCS effects over the motor cortex [2,3]; although more recent research has also focused on its effects over the dorsolateral prefrontal cortex (DLPFC), particularly to treat psychiatric disorders [4] and to modulate cognitive performance [5–8]. These cognitive results can be useful to predict treatment outcome.Effect of Repetitive Transcranial Magnetic Stimulation on Physical Function and Motor Signs in Parkinson's Disease: A Systematic Review and Meta-Analysis
The progressive loss of dopaminergic neurons in Parkinson's disease (PD) results in functional disruption within the cortico-basal ganglia–thalamo-cortical motor circuit [1,2]. In particular, there is an excessive inhibition of thalamocortical projection to various cortical targets, including the primary motor cortex (M1), supplementary motor cortex (SMA) and dorsolateral prefrontal cortex (DLPFC) [2–4]. Abnormal neural activities in these cortical areas were evident in neuroimaging studies that showed hypo-activations of SMA and DLPFC [5].The Clinical TMS Society Consensus Review and Treatment Recommendations for TMS Therapy for Major Depressive Disorder
TMS therapy uses a computerized, electromechanical medical device to produce and deliver non-invasive, magnetic stimulation using brief duration, rapidly alternating, or pulsed, magnetic fields to induce electrical currents directed at spatially discrete regions of the cerebral cortex. This method of cortical stimulation by application of brief magnetic pulses to the head is known as transcranial magnetic stimulation or TMS. When pulses of TMS are delivered repetitively, this is called repetitive TMS, or rTMS.Effects of Anodal Transcranial Direct Current Stimulation on Working Memory: A Systematic Review and Meta-Analysis of Findings From Healthy and Neuropsychiatric Populations
Cognitive deficits, including working memory (WM) impairment, are core features of a number of neuropsychiatric disorders, contributing substantially to burden of disease and remaining largely refractory to conventional drug-based therapies [1–3]. Transcranial direct current stimulation (tDCS) is emerging as a safe and relatively inexpensive means of modulating both psychological and physiological processes through the non-invasive application of low-voltage currents to the brain [4]. Indeed, a number of studies have now reported beneficial effects of tDCS on memory function in neuropsychiatric populations [5–12] as well as in healthy individuals [13–24].A Meta-analysis of the Cortical Silent Period in Epilepsies
The cortical silent period (CSP) following transcranial magnetic stimulation reflects GABAB-mediated inhibition in the primary motor cortex (M1) and could contribute to understand the pathophysiological substrates of epileptic conditions. Increased CSP duration has been reported in idiopathic generalized epilepsy (IGE) and in partial epilepsy (PE) involving the M1, although other studies yielded discordant findings. We used meta-analysis to systematically assess the consistency of CSP changes in untreated patients with epilepsies.Efficacy and Time Course of Theta Burst Stimulation in Healthy Humans
In the past decade research has shown that continuous (cTBS) and intermittent theta burst stimulation (iTBS) alter neuronal excitability levels in the primary motor cortex.Safety of Noninvasive Brain Stimulation in Children and Adolescents
Noninvasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial current stimulation (tCS) have the potential to mitigate a variety of symptoms associated with neurological and psychiatric conditions, including stroke, cerebral palsy, autism, depression, and Tourette syndrome. While the safety of these modalities has been established in adults, there is a paucity of research assessing the safety of NIBS among children.A Consensus Panel Review of Central Nervous System Effects of the Exposure to Low-Intensity Extremely Low-Frequency Magnetic Fields
A large number of studies explored the biological effects of extremely low-frequency (0–300 Hz) magnetic fields (ELF-MFs) on nervous system both at cellular and at system level in the intact human brain reporting several functional changes. However, the results of different studies are quite variable and the mechanisms of action of ELF-MFs are still poorly defined. The aim of this paper is to provide a comprehensive review of the effects of ELF-MFs on nervous system.
