scholarly journals Modulating parameters of excitability during and after transcranial direct current stimulation of the human motor cortex

2005 ◽  
Vol 568 (1) ◽  
pp. 291-303 ◽  
Author(s):  
Michael A. Nitsche ◽  
Antje Seeber ◽  
Kai Frommann ◽  
Cornelia Carmen Klein ◽  
Christian Rochford ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Human Motor Cortex ◽  
Direct Current Stimulation ◽  
Human Motor ◽  
Stimulation Of

Time course of the induction of homeostatic plasticity generated by repeated transcranial direct current stimulation of the human motor cortex

2011 ◽  
Vol 105 (3) ◽  
pp. 1141-1149 ◽  
Author(s):  
K. Fricke ◽  
A. A. Seeber ◽  
N. Thirugnanasambandam ◽  
W. Paulus ◽  
M. A. Nitsche ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Homeostatic Plasticity ◽  
Network Activity ◽  
Time Interval ◽  
Human Motor Cortex ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs ◽  
Human Motor

Several mechanisms have been proposed that control the amount of plasticity in neuronal circuits and guarantee dynamic stability of neuronal networks. Homeostatic plasticity suggests that the ease with which a synaptic connection is facilitated/suppressed depends on the previous amount of network activity. We describe how such homeostatic-like interactions depend on the time interval between two conditioning protocols and on the duration of the preconditioning protocol. We used transcranial direct current stimulation (tDCS) to produce short-lasting plasticity in the motor cortex of healthy humans. In the main experiment, we compared the aftereffect of a single 5-min session of anodal or cathodal tDCS with the effect of a 5-min tDCS session preceded by an identical 5-min conditioning session administered 30, 3, or 0 min beforehand. Five-minute anodal tDCS increases excitability for about 5 min. The same duration of cathodal tDCS reduces excitability. Increasing the duration of tDCS to 10 min prolongs the duration of the effects. If two 5-min periods of tDCS are applied with a 30-min break between them, the effect of the second period of tDCS is identical to that of 5-min stimulation alone. If the break is only 3 min, then the second session has the opposite effect to 5-min tDCS given alone. Control experiments show that these shifts in the direction of plasticity evolve during the 10 min after the first tDCS session and depend on the duration of the first tDCS but not on intracortical inhibition and facilitation. The results are compatible with a time-dependent “homeostatic-like” rule governing the response of the human motor cortex to plasticity probing protocols.

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