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Anodal tDCS over the Primary Motor Cortex Facilitates Long-Term Memory Formation Reflecting Use-Dependent Plasticity.

Rroji O, van Kuyck K, Nuttin B, Wenderoth N - PLoS ONE (2015)

Bottom Line: Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001).This effect was large (Cohen's d=1.01) and all but one subject followed the group trend.Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

View Article: PubMed Central - PubMed

Affiliation: Department of Kinesiology, Research Center for Movement Control and Neuroplasticity, KU Leuven, Leuven, Belgium.

ABSTRACT
Previous research suggests that anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) modulates NMDA receptor dependent processes that mediate synaptic plasticity. Here we test this proposal by applying anodal versus sham tDCS while subjects practiced to flex the thumb as fast as possible (ballistic movements). Repetitive practice of this task has been shown to result in performance improvements that reflect use-dependent plasticity resulting from NMDA receptor mediated, long-term potentiation (LTP)-like processes. Using a double-blind within-subject cross-over design, subjects (n=14) participated either in an anodal or a sham tDCS session which were at least 3 months apart. Sham or anodal tDCS (1 mA) was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions (p < 0.001) and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001). This effect was large (Cohen's d=1.01) and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

No MeSH data available.


Experimental Setup.A) Subjects performed discrete ballistic thumb flexion movements with the forearm and fingers fixated. B) Constant current stimulation was delivered with the anode (red) placed over the M1 contralateral to the moving thumb and the cathode (black) over the ipsilateral shoulder. C) General experimental design.
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pone.0127270.g001: Experimental Setup.A) Subjects performed discrete ballistic thumb flexion movements with the forearm and fingers fixated. B) Constant current stimulation was delivered with the anode (red) placed over the M1 contralateral to the moving thumb and the cathode (black) over the ipsilateral shoulder. C) General experimental design.

Mentions: Subjects were seated in a comfortable chair and had to perform discrete ballistic thumb flexion movements with their non-dominant hand (Fig 1A). The forearm was fixed to a wooden construction and the four fingers were immobilized by a velcro strap while the thumb was unconstrained and could move freely. A Polhemus Fastrak sensor (sampling rate of 120 Hz, spatial resolution of 0.0006 cm) was fixed on the nail of the thumb to measure 3D kinematics and provide online feedback. This sensor location was used because previous research has shown that it is highly reproducible between sessions [31]. 3D kinematic data was used to calculate the absolute velocity: Vi = sqrt ((Xi-Xi-1)2 + (Yi-Yi-1)2 + (Zi-Zi-1)2) / (ti-ti-1) where X, Y and Z represent displacement in three dimensions, t the time and i the index of the current data point. For each movement the velocity profile was displayed on a computer screen in front of the subject to provide performance feedback. The maximum velocity was also displayed for each trial and continuously updated providing subjects with an indication of how their performance changed across training.


Anodal tDCS over the Primary Motor Cortex Facilitates Long-Term Memory Formation Reflecting Use-Dependent Plasticity.

Rroji O, van Kuyck K, Nuttin B, Wenderoth N - PLoS ONE (2015)

Experimental Setup.A) Subjects performed discrete ballistic thumb flexion movements with the forearm and fingers fixated. B) Constant current stimulation was delivered with the anode (red) placed over the M1 contralateral to the moving thumb and the cathode (black) over the ipsilateral shoulder. C) General experimental design.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440644&req=5

pone.0127270.g001: Experimental Setup.A) Subjects performed discrete ballistic thumb flexion movements with the forearm and fingers fixated. B) Constant current stimulation was delivered with the anode (red) placed over the M1 contralateral to the moving thumb and the cathode (black) over the ipsilateral shoulder. C) General experimental design.
Mentions: Subjects were seated in a comfortable chair and had to perform discrete ballistic thumb flexion movements with their non-dominant hand (Fig 1A). The forearm was fixed to a wooden construction and the four fingers were immobilized by a velcro strap while the thumb was unconstrained and could move freely. A Polhemus Fastrak sensor (sampling rate of 120 Hz, spatial resolution of 0.0006 cm) was fixed on the nail of the thumb to measure 3D kinematics and provide online feedback. This sensor location was used because previous research has shown that it is highly reproducible between sessions [31]. 3D kinematic data was used to calculate the absolute velocity: Vi = sqrt ((Xi-Xi-1)2 + (Yi-Yi-1)2 + (Zi-Zi-1)2) / (ti-ti-1) where X, Y and Z represent displacement in three dimensions, t the time and i the index of the current data point. For each movement the velocity profile was displayed on a computer screen in front of the subject to provide performance feedback. The maximum velocity was also displayed for each trial and continuously updated providing subjects with an indication of how their performance changed across training.

Bottom Line: Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001).This effect was large (Cohen's d=1.01) and all but one subject followed the group trend.Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

View Article: PubMed Central - PubMed

Affiliation: Department of Kinesiology, Research Center for Movement Control and Neuroplasticity, KU Leuven, Leuven, Belgium.

ABSTRACT
Previous research suggests that anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) modulates NMDA receptor dependent processes that mediate synaptic plasticity. Here we test this proposal by applying anodal versus sham tDCS while subjects practiced to flex the thumb as fast as possible (ballistic movements). Repetitive practice of this task has been shown to result in performance improvements that reflect use-dependent plasticity resulting from NMDA receptor mediated, long-term potentiation (LTP)-like processes. Using a double-blind within-subject cross-over design, subjects (n=14) participated either in an anodal or a sham tDCS session which were at least 3 months apart. Sham or anodal tDCS (1 mA) was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions (p < 0.001) and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001). This effect was large (Cohen's d=1.01) and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

No MeSH data available.