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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).Modulation of cortical responses by transcranial direct current stimulation of dorsolateral prefrontal cortex: A resting-state EEG and TMS-EEG study
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Testing assumptions on prefrontal transcranial direct current stimulation: Comparison of electrode montages using multimodal fMRI
Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been widely applied in cognitive neurosciences and advocated as a therapeutic intervention, e.g. in major depressive disorder. Although several targets and protocols have been suggested, comparative studies of tDCS parameters, particularly electrode montages and their cortical targets, are still lacking.Modulation of motor cortex excitability predicts antidepressant response to prefrontal cortex repetitive transcranial magnetic stimulation
Repetitive transcranial magnetic stimulation (rTMS) targeting the left dorsolateral prefrontal cortex (DLPFC) is a treatment option for patients with medication-resistant major depressive disorder (MDD). However, antidepressant response is variable and there are currently no response predictors with sufficient accuracy for clinical use.A single session of prefrontal cortex transcranial direct current stimulation does not modulate implicit task sequence learning and consolidation
Transcranial direct current stimulation (tDCS) is assumed to affect cortical excitability and dependent on the specific stimulation conditions either to increase or decrease learning.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.Safety, Tolerability, Blinding Efficacy and Behavioural Effects of a Novel MRI-Compatible, High-Definition tDCS Set-Up
Transcranial direct current stimulation (tDCS) can improve cognition, motor function and learning in health and disease [1–4]. Conventional-tDCS set-ups typically employ two rubber electrodes (e.g., 5 × 5 or 5 × 7 cm2) and the ingoing current is projected from one electrode that is attached over a cortical target region to a return electrode that is attached over a different cortical area or an extracranial region [5]. This set-up may result in relatively non-focal stimulation due to the size of the electrodes, and regions between the two electrodes may also be affected as demonstrated by recent current modelling studies [6,7].Endogenous Action Selection Processes in Dorsolateral Prefrontal Cortex Contribute to Sense of Agency: A Meta-Analysis of tDCS Studies of ‘Intentional Binding’
Performing a voluntary action that produces an intended outcome is accompanied by a characteristic subjective experience, referred to as ‘sense of agency’. Sense of agency is a fundamental feature of normal human mental life [1]. Indeed, many neurological and psychiatric disorders involve deficits in sense of agency [2], most notably the positive symptoms of schizophrenia [3].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].The Efficacy and Safety of Low Frequency Repetitive Transcranial Magnetic Stimulation for Treatment-resistant Depression: The Results From a Large Multicenter French RCT
The aim of this study was to assess whether the combination of low frequency repetitive transcranial magnetic stimulation (rTMS) and venlafaxine (150–225 mg/day) is effective and safe for treatment-resistant unipolar depression (TRD).Concurrent Cognitive Control Training Augments the Antidepressant Efficacy of tDCS: A Pilot Study
Major depressive disorder (MDD) is frequently associated with underactivity of the dorsolateral prefrontal cortex (DLPFC) which has led to this brain region being identified as an important target for the development of neurobiological treatments. Transcranial direct current stimulation (tDCS) administered to the DLPFC has antidepressant efficacy, however the magnitude of antidepressant outcomes are limited. Concurrent cognitive activity has been shown to enhance tDCS induced stimulation effects.Transcranial Magnetic Stimulation of the Left Dorsolateral Prefrontal Cortex Decreases Cue-induced Nicotine Craving and EEG Delta Power
TMS has high potential as smoking cessation treatment. However, the neural mechanisms underlying TMS induced reduction of tobacco craving remain unclear. Electroencephalographic (EEG) delta frequency has been associated with the activity of the dopaminergic brain reward system, which is crucial for nicotine induced effects, and decreases after nicotine admission in smokers.
