scholarly journals Contribution of axonal orientation to pathway-dependent modulation of excitatory transmission by direct current stimulation in isolated rat hippocampus

2012 ◽  
Vol 107 (7) ◽  
pp. 1881-1889 ◽  
Author(s):  
Anatoli Y. Kabakov ◽  
Paul A. Muller ◽  
Alvaro Pascual-Leone ◽  
Frances E. Jensen ◽  
Alexander Rotenberg
Keyword(s):  
Direct Current ◽  
Cortical Excitability ◽  
Mossy Fiber ◽  
Region Of Interest ◽  
Electrical Current ◽  
Signal Propagation ◽  
Field Vector ◽  
Cortical Region ◽  
Direct Current Stimulation

Transcranial direct current stimulation (tDCS) is a method for modulating cortical excitability by weak constant electrical current that is applied through scalp electrodes. Although often described in terms of anodal or cathodal stimulation, depending on which scalp electrode pole is proximal to the cortical region of interest, it is the orientation of neuronal structures relative to the direct current (DC) vector that determines the effect of tDCS. To investigate the contribution of neural pathway orientation, we studied DCS-mediated neuromodulation in an in vitro rat hippocampal slice preparation. We examined the contribution of dendritic orientation to the direct current stimulation (DCS) neuromodulatory effect by recording field excitatory postsynaptic potentials (fEPSPs) in apical and basal dendrites of CA1 neurons within a constant DC field. In addition, we assessed the contribution of axonal orientation by recording CA1 and CA3 apical fEPSPs generated by stimulation of oppositely oriented Schaffer collateral and mossy fiber axons, respectively, during DCS. Finally, nonsynaptic excitatory signal propagation was measured along antidromically stimulated CA1 axons at different DCS amplitudes and polarity. We find that modulation of both the fEPSP and population spike depends on axonal orientation relative to the electric field vector. Axonal orientation determines whether the DC field is excitatory or inhibitory and dendritic orientation affects the magnitude, but not the overall direction, of the DC effect. These data suggest that tDCS may oppositely affect neurons in a stimulated cortical volume if these neurons are excited by oppositely orientated axons in a constant electrical field.

scholarly journals Cerebellar transcranial direct current stimulation reconfigurates static and dynamic functional connectivity of the resting-state networks

2020 ◽  
Author(s):  
Fatma Grami ◽  
Giovanni de Marco ◽  
Florian Bodranghien ◽  
Mario Manto ◽  
C. Habas
Keyword(s):  
Functional Connectivity ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Resting State ◽  
Cortical Excitability ◽  
Region Of Interest ◽  
Temporal Variations ◽  
Functional Changes ◽  
Direct Current Stimulation ◽  
The Right

Abstract Background Transcranial direct current stimulation (tDCS) of the cerebellum dynamically modulates cerebello-thalamo-cortical excitability in a polarity-specific manner during motor, visuo- motor and cognitive tasks. It remains to be established whether tDCS of the cerebellum impact also on resting-state intrinsically connected networks (ICNs). Such impact would open novel research and therapeutical doors for the neuromodulation of ICNs in human. Method: We combined tDCS applied over the right cerebellum and fMRI to investigate tDCS- induced resting-state intrinsic functional reconfiguration, using a randomized, sham-controlled design. fMRI data were recorded both before and after real anodal stimulation (2 mA, 20 min) or sham tDCS in 12 right-handed healthy volunteers. We resorted to a region-of-interest static correlational analysis and to a sliding window analysis to assess temporal variations in resting state FC between the cerebellar lobule VII and nodes of the main ICNs. Results After real tDCS and compared with sham tDCS, functional changes were observed between the cerebellum and ICNs. Static FC showed enhanced or decreased correlation between cerebellum and brain areas belonging to visual, default-mode (DMN), sensorimotor and salience networks (SN) (p-corrected < 0.05). The temporal variability (TV) of BOLD signal was significantly modified after tDCS displaying in particular a lesser TV between the whole lobule VII and DMN and central executive network and a greater TV between crus 2 and SN. Static and dynamic FC was also modified between cerebellar lobuli. Conclusion These results demonstrate short- and long-range static and majorly dynamic effects of tDCS stimulation of the cerebellum affecting distinct resting-state ICNs, as well as intracerebellar functional connectivity, so that tDCS of the cerebellum appears as a non-invasive tool reconfigurating the dynamics of ICNs.

scholarly journals Transcranial Direct Current Stimulation: A Novel Neuromodulation Technique?

2014 ◽  
pp. iv
Author(s):  
Sujit Sarkhel
Keyword(s):  
Major Depression ◽  
Direct Current ◽  
Brain Stimulation ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Electrical Current ◽  
Therapeutic Effects ◽  
Direct Current Stimulation ◽  
Non Invasive ◽  
Direct Electrical Current

Transcranial direct current stimulation (tDCS) is a minimally invasive form of brainstimulation that uses direct electrical current to alter cortical excitability. During thisprocess, a weak, direct electrical current (1 to 2 mA) is applied using scalp surface electrodes.Anodal stimulation increases cortical excitability and cathodal stimulation decreases it. Thechanges in cortical excitability probably arise from the depolarization and hyperpolarization ofneurons.1 Interest in this treatment modality had begun way back in the 1960s but graduallywaned. Renewed interest began emerging in the 1990s following spurt in neuromodulationresearch using transcranial magnetic stimulation (TMS). Based on the theory of hypoactivityin left prefrontal cortex in depression, anodal tDCS has been applied to the left hemisphere toincrease activity and cathodal tDCS to the right hemisphere to decrease activity in order toresolve depression. Several open label and randomized controlled trials have been conductedto examine the efficacy of tDCS in treating major depression some of which have yieldedpositive results.2, 3, 4, tDCS has also been tried in Parkinson’s disease, schizophrenia, posttraumatic stress disorder and substance use. 5, 6,7 tDCS is a cheap and non-invasive techniquewith minimal side effects like headache and itchiness and redness at the site of stimulation.It will require few years of systematic research to find out whether tDCS emerges as a cheap,non-invasive and above all, effective method for treatment of psychiatric disorders or it goesinto oblivion as another “fancy” brain gadget!REFERENCES1. Bindman LJ, Lippold OC, Redfearn JW. The action of brief polarizing currents on the cerebral cortex ofthe rat (1) during current flow and (2) in the production of long-lasting after-effects. J Physiol. 1964; 172 :369-382.2. Boggio PS, Rigonatti SP, Ribeiro RB, et al. A randomized, double-blind clinical trial on the efficacy of cortical direct currentstimulation for the treatment of major depression. Int J Neuropsychopharmacol. 2008; 11 : 249-254.3. Brunoni AR, Ferrucci R, Bortolomasi M, et al. Transcranial direct current stimulation (tDCS) in unipolar vs. bipolar depressivedisorder. Prog Neuropsychopharmacol Biol Psychiatry. 2011; 35 : 96-101.4. Fregni F, Boggio PS, Nitsche MA, et al. Cognitive effects of repeated sessions of transcranial direct current stimulation in patientswith depression. Depress Anxiety. 2006; 23 : 482-484.5. Kuo MF, Paulus W, Nitsche MA. Therapeutic effects of non-invasive brain stimulation with direct currents (tDCS) in neuropsychiatricdiseases.Neuroimage. 2014; 85 : 948-9606. Jansen JM, Daams JG, Koeter MW, etal.Effects of non-invasive neurostimulation on craving : a meta-analysis. Neuroscience BiobehavRev 2013; 37 : 2472-24807. Marin MF, Camprodon JA, Dougherty DD, et al. Device-based brain stimulation to augment fear extinction : implications for PTSDtreatment and beyond. Depress Anxiety 2014; 10 : 1-10

scholarly journals Cerebellar transcranial direct current stimulation reconfigurates static and dynamic functional connectivity of the resting-state networks

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
F. Grami ◽  
G. de Marco ◽  
F. Bodranghien ◽  
M. Manto ◽  
C. Habas
Keyword(s):  
Functional Connectivity ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Resting State ◽  
Cortical Excitability ◽  
Region Of Interest ◽  
Temporal Variations ◽  
Functional Changes ◽  
Direct Current Stimulation ◽  
The Right

Abstract Background Transcranial direct current stimulation (tDCS) of the cerebellum dynamically modulates cerebello-thalamo-cortical excitability in a polarity-specific manner during motor, visuo- motor and cognitive tasks. It remains to be established whether tDCS of the cerebellum impact also on resting-state intrinsically connected networks (ICNs). Such impact would open novel research and therapeutical doors for the neuromodulation of ICNs in human. Method We combined tDCS applied over the right cerebellum and fMRI to investigate tDCS- induced resting-state intrinsic functional reconfiguration, using a randomized, sham-controlled design. fMRI data were recorded both before and after real anodal stimulation (2 mA, 20 min) or sham tDCS in 12 right-handed healthy volunteers. We resorted to a region-of-interest static correlational analysis and to a sliding window analysis to assess temporal variations in resting state FC between the cerebellar lobule VII and nodes of the main ICNs. Results After real tDCS and compared with sham tDCS, functional changes were observed between the cerebellum and ICNs. Static FC showed enhanced or decreased correlation between cerebellum and brain areas belonging to visual, default-mode (DMN), sensorimotor and salience networks (SN) (p-corrected < 0.05). The temporal variability (TV) of BOLD signal was significantly modified after tDCS displaying in particular a lesser TV between the whole lobule VII and DMN and central executive network and a greater TV between crus 2 and SN. Static and dynamic FC was also modified between cerebellar lobuli. Conclusion These results demonstrate short- and long-range static and majorly dynamic effects of tDCS stimulation of the cerebellum affecting distinct resting-state ICNs, as well as intracerebellar functional connectivity, so that tDCS of the cerebellum appears as a non-invasive tool reconfigurating the dynamics of ICNs.

scholarly journals The effects of transcranial direct current stimulation on gait in patients with Parkinson’s disease: a systematic review

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Fateme Pol ◽  
Mohammad Ali Salehinejad ◽  
Hamzeh Baharlouei ◽  
Michael A. Nitsche
Keyword(s):  
Systematic Review ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Randomized Clinical Trials ◽  
Cortical Excitability ◽  
Experimental Studies ◽  
Gait Rehabilitation ◽  
Direct Current Stimulation

Abstract Background Gait problems are an important symptom in Parkinson’s disease (PD), a progressive neurodegenerative disease. Transcranial direct current stimulation (tDCS) is a neuromodulatory intervention that can modulate cortical excitability of the gait-related regions. Despite an increasing number of gait-related tDCS studies in PD, the efficacy of this technique for improving gait has not been systematically investigated yet. Here, we aimed to systematically explore the effects of tDCS on gait in PD, based on available experimental studies. Methods Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach, PubMed, Web of Science, Scopus, and PEDro databases were searched for randomized clinical trials assessing the effect of tDCS on gait in patients with PD. Results Eighteen studies were included in this systematic review. Overall, tDCS targeting the motor cortex and supplementary motor area bilaterally seems to be promising for gait rehabilitation in PD. Studies of tDCS targeting the dorosolateral prefrontal cortex or cerebellum showed more heterogeneous results. More studies are needed to systematically compare the efficacy of different tDCS protocols, including protocols applying tDCS alone and/or in combination with conventional gait rehabilitation treatment in PD. Conclusions tDCS is a promising intervention approach to improving gait in PD. Anodal tDCS over the motor areas has shown a positive effect on gait, but stimulation of other areas is less promising. However, the heterogeneities of methods and results have made it difficult to draw firm conclusions. Therefore, systematic explorations of tDCS protocols are required to optimize the efficacy.

scholarly journals Gender-specific modulation of short-term neuroplasticity in the visual cortex induced by transcranial direct current stimulation

2008 ◽  
Vol 25 (1) ◽  
pp. 77-81 ◽  
Author(s):  
LEILA CHAIEB ◽  
ANDREA ANTAL ◽  
WALTER PAULUS
Keyword(s):  
Sex Differences ◽  
Visual Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Gonadal Hormones ◽  
Study Data ◽  
Short Term ◽  
Direct Current Stimulation ◽  
Significant Difference

Transcranial direct current stimulation (tDCS) is a non-invasive method of modulating levels of cortical excitability. In this study, data gathered over a number of previously conducted experiments before and after tDCS, has been re-analyzed to investigate correlations between sex differences with respect to neuroplastic effects. Visual evoked potentials (VEPs), phosphene thresholds (PTs), and contrast sensitivity measurements (CSs) are used as indicators of the excitability of the primary visual cortex. The data revealed that cathodally induced excitability effects 10 min post stimulation with tDCS, showed no significant difference between genders. However, stimulation in the anodal direction revealed sex-specific effects: in women, anodal stimulation heightened cortical excitability significantly when compared to the age-matched male subject group. There was no significant difference between male and female subjects immediately after stimulation. These results indicate that sex differences exist within the visual cortex of humans, and may be subject to the influences of modulatory neurotransmitters or gonadal hormones which mirror short-term neuroplastic effects.

scholarly journals S192. EFFECTS OF NICOTINE INTAKE ON NEUROPLASTICITY IN SMOKING AND NON-SMOKING PATIENTS WITH SCHIZOPHRENIA

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S111-S112
Author(s):  
Benjamin Pross ◽  
Patrick Schulz ◽  
Duygu Güler ◽  
Irina Papazova ◽  
Elias Wagner ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Environmental Changes ◽  
Cortical Plasticity ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Receptor Activation ◽  
Pathophysiological Mechanism ◽  
Direct Current Stimulation ◽  
Nicotine Consumption

Abstract Background Cortical plasticity – the ability to reorganize synaptic connections and adapt to environmental changes – appears to be impaired in schizophrenia patients. Results suggest the dysfunctional plasticity to be a key pathophysiological mechanism. Different non-invasive brain stimulation (NIBS) techniques have been used to modulate and induce cortical plasticity. In healthy subjects, nicotine was shown to play an important role in plasticity induction and is capable to alter cortical excitability and plasticity, induced by NIBS techniques. Our goal was to investigate the promising effects of a nicotine receptor activation done by Varenicline and the combination with anodal transcranial direct current stimulation (a-tDCS) on neuroplastic changes in schizophrenia patients. Methods Our sample consisted out of twenty-four individuals with schizophrenia, twelve smokers and twelve non-smokers. Every participant received Varenicline and Placebo, combined with anodal transcranial direct current stimulation (a-tDCS), to induce non-focal plasticity. We inferred plasticity changes by monitoring changes in cortical excitability. This was done via motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). The MEPs were recorded before and three hours after Varenicline/Placebo intake. Following the direct current stimulation, we monitored excitability changes for up to one hour. Results Significant effects through the mere Varenicline consumption or withdrawal effects could not be found in any group. However, we observed a numeric temporary decrease of excitability after a-tDCS in non-smokers following Varenicline intake. This decrease compared to the placebo condition was visible 20 minutes after a-tDCS but vanished over time. Smokers did not show any excitability changes after a-tDCS and the nicotinic receptor stimulation did not show any influence. Excitability changes after stimulation in contrast to the baseline measurement were not evident. Discussion Our results show that an activation of nicotinic receptors in schizophrenia patients does not induce excitability changes. The modulating effect of nicotine in plasticity induction via anodal transcranial direct current stimulation could not be confirmed for patients with schizophrenia. We could show that chronic nicotine consumption in patients with schizophrenia or nicotine withdrawal does not lead to fundamental excitability changes. Acute nicotine consumption has only small effects on cortical excitability in non-smokers.

Sign in / Sign up

Export Citation Format

Share Document