scholarly journals Immediate and after effects of transcranial direct-current stimulation in the mouse primary somatosensory cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carlos A. Sánchez-León ◽  
Isabel Cordones ◽  
Claudia Ammann ◽  
José M. Ausín ◽  
María A. Gómez-Climent ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Immunohistochemical Analysis ◽  
Gamma Oscillations ◽  
Primary Somatosensory Cortex ◽  
After Effects ◽  
Direct Current Stimulation ◽  
Sensory Evoked ◽  
Cathodal Stimulation

AbstractTranscranial direct-current stimulation (tDCS) is a non-invasive brain stimulation technique consisting in the application of weak electric currents on the scalp. Although previous studies have demonstrated the clinical value of tDCS for modulating sensory, motor, and cognitive functions, there are still huge gaps in the knowledge of the underlying physiological mechanisms. To define the immediate impact as well as the after effects of tDCS on sensory processing, we first performed electrophysiological recordings in primary somatosensory cortex (S1) of alert mice during and after administration of S1-tDCS, and followed up with immunohistochemical analysis of the stimulated brain regions. During the application of cathodal and anodal transcranial currents we observed polarity-specific bidirectional changes in the N1 component of the sensory-evoked potentials (SEPs) and associated gamma oscillations. On the other hand, 20 min of cathodal stimulation produced significant after-effects including a decreased SEP amplitude for up to 30 min, a power reduction in the 20–80 Hz range and a decrease in gamma event related synchronization (ERS). In contrast, no significant changes in SEP amplitude or power analysis were observed after anodal stimulation except for a significant increase in gamma ERS after tDCS cessation. The polarity-specific differences of these after effects were corroborated by immunohistochemical analysis, which revealed an unbalance of GAD 65–67 immunoreactivity between the stimulated versus non-stimulated S1 region only after cathodal tDCS. These results highlight the differences between immediate and after effects of tDCS, as well as the asymmetric after effects induced by anodal and cathodal stimulation.

scholarly journals Immediate and long-term effects of transcranial direct-current stimulation in the mouse primary somatosensory cortex

2020 ◽  
Author(s):  
Carlos A. Sánchez-León ◽  
Isabel Cordones ◽  
Claudia Ammann ◽  
José M. Ausín ◽  
María A. Gómez-Climent ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Immunohistochemical Analysis ◽  
Primary Somatosensory Cortex ◽  
Long Term Effects ◽  
After Effects ◽  
Long Term Changes ◽  
Cathodal Stimulation

AbstractTranscranial direct-current stimulation (tDCS) is a non-invasive brain stimulation technique consisting in the application of weak electric currents on the scalp. Although previous studies have demonstrated the clinical value of tDCS for modulating sensory, motor, and cognitive functions, there are still huge gaps in the knowledge of the underlying physiological mechanisms. To define the immediate impact as well as the after-effects of tDCS on sensory processing, we first performed electrophysiological recordings in primary somatosensory cortex (S1) of alert mice during and after administration of S1-tDCS, and followed up with immunohistochemical analysis of the stimulated brain regions. During the application of cathodal and anodal transcranial currents we observed polarity-specific bidirectional changes in the N1 component of the sensory-evoked potentials (SEPs) and associated gamma oscillations. Regarding the long-term effects observed after 20 min of tDCS, cathodal stimulation produced significant after-effects including a decreased SEP amplitude for up to 30 min, a power reduction in the 20-80 Hz range and a decrease in gamma event related synchronization (ERS). In contrast, no significant long-term changes in SEP amplitude or power analysis were observed after anodal stimulation except for a significant increase in gamma ERS after tDCS cessation. The polarity-specific differences of these long-term effects were corroborated by immunohistochemical analysis, which revealed an unbalance of GAD 65-67 immunoreactivity between the stimulated vs. non-stimulated S1 region only after cathodal tDCS. These results highlight the differences between immediate and long-term effects of tDCS, as well as the asymmetric long-term changes induced by anodal and cathodal stimulation.Significance StatementHere we provide a first glimpse at the immediate and long-term impact of tDCS on neural processing in alert animals. The obtained results highlight the complexity of tDCS-associated effects, which include both bidirectional as well as asymmetrical modulation depending on the polarity of the stimulation. This asymmetry suggests the implication of different mechanisms underlying the long-term effects induced by anodal and cathodal transcranial currents. Identifying and defining these effects and its associated mechanisms is crucial to help design effective protocols for clinical applications.

scholarly journals Effects of transcranial direct current stimulation of primary somatosensory cortex on vibrotactile detection and discrimination

2016 ◽  
Vol 115 (4) ◽  
pp. 1978-1987 ◽  
Author(s):  
Sara Labbé ◽  
El-Mehdi Meftah ◽  
C. Elaine Chapman
Keyword(s):  
Somatosensory Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Middle Finger ◽  
Primary Somatosensory Cortex ◽  
Direct Current Stimulation ◽  
Stimulus Response ◽  
Neuronal Mechanisms ◽  
Vibrotactile Perception ◽  
Stimulation Of

Anodal transcranial direct current stimulation (a-tDCS) of primary somatosensory cortex (S1) has been shown to enhance tactile spatial acuity, but there is little information as to the underlying neuronal mechanisms. We examined vibrotactile perception on the distal phalanx of the middle finger before, during, and after contralateral S1 tDCS [a-, cathodal (c)-, and sham (s)-tDCS]. The experiments tested our shift-gain hypothesis, which predicted that a-tDCS would decrease vibrotactile detection and discrimination thresholds (leftward shift of the stimulus-response function with increased gain/slope) relative to s-tDCS, whereas c-tDCS would have the opposite effects (relative to s-tDCS). The results showed that weak a-tDCS (1 mA, 20 min) led to a reduction in both vibrotactile detection and discrimination thresholds to 73–76% of baseline during the application of the stimulation in subjects categorized as responders. These effects persisted after the end of a-tDCS but were absent 30 min later. Most, but not all, subjects showed a decrease in threshold (8/12 for detection; 9/12 for discrimination). Intersubject variability was explained by a ceiling effect in the discrimination task. c-tDCS had no significant effect on either detection or discrimination threshold. Taken together, our results supported our shift-gain hypothesis for a-tDCS but not c-tDCS.

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