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Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

Bastani A, Jaberzadeh S - PLoS ONE (2013)

Bottom Line: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs) of 0.013, 0.029, 0.058 and 0.083 mA/cm(2) were applied on twelve right-handed (mean age 34.5±10.32 yrs) healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2) respectively.This study found that a-tDCS with a current density of 0.013 mA/cm(2) induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2).The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia. andisheh.bastanijahromi@monash.edu

ABSTRACT

Background: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set.

Objective/hypothesis: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS) current densities on corticospinal excitability.

Methods: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs) of 0.013, 0.029, 0.058 and 0.083 mA/cm(2) were applied on twelve right-handed (mean age 34.5±10.32 yrs) healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2) respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR) was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter.

Results: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2) and 0.029 mA/cm(2) (P = 0.003). There were no significant differences between excitability changes for the 0.013 mA/cm(2) and 0.058 mA/cm(2) (P = 0.080) or 0.013 mA/cm(2) and 0.083 mA/cm(2) (P = 0.484) conditions.

Conclusion: This study found that a-tDCS with a current density of 0.013 mA/cm(2) induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2). The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

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Percentage increase in corticospinal excitability after the intervention.The asterisks mark significant differences between ECR muscle MEP amplitudes after the end of a-tDCS in all time points of T0, T10, T20 and T30. Error bars represent SEM.
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pone-0072254-g003: Percentage increase in corticospinal excitability after the intervention.The asterisks mark significant differences between ECR muscle MEP amplitudes after the end of a-tDCS in all time points of T0, T10, T20 and T30. Error bars represent SEM.

Mentions: We observed no significant changes between different time points of a-tDCS within each D1, D3 and D4 CD conditions (P>0.05). However, in the D2 condition, we found significant differences between the amplitudes of ECR MEPs 20 and 30 minutes after the end of stimulation (P<0.05) (Figure 2). Also the result of post hoc comparisons showed significant differences between D1–D2, D2–D4 and D3–D4 (P<0.05) in all time points of T0, T10, T20 and T30 (Figure 3).


Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

Bastani A, Jaberzadeh S - PLoS ONE (2013)

Percentage increase in corticospinal excitability after the intervention.The asterisks mark significant differences between ECR muscle MEP amplitudes after the end of a-tDCS in all time points of T0, T10, T20 and T30. Error bars represent SEM.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3750044&req=5

pone-0072254-g003: Percentage increase in corticospinal excitability after the intervention.The asterisks mark significant differences between ECR muscle MEP amplitudes after the end of a-tDCS in all time points of T0, T10, T20 and T30. Error bars represent SEM.
Mentions: We observed no significant changes between different time points of a-tDCS within each D1, D3 and D4 CD conditions (P>0.05). However, in the D2 condition, we found significant differences between the amplitudes of ECR MEPs 20 and 30 minutes after the end of stimulation (P<0.05) (Figure 2). Also the result of post hoc comparisons showed significant differences between D1–D2, D2–D4 and D3–D4 (P<0.05) in all time points of T0, T10, T20 and T30 (Figure 3).

Bottom Line: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs) of 0.013, 0.029, 0.058 and 0.083 mA/cm(2) were applied on twelve right-handed (mean age 34.5±10.32 yrs) healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2) respectively.This study found that a-tDCS with a current density of 0.013 mA/cm(2) induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2).The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia. andisheh.bastanijahromi@monash.edu

ABSTRACT

Background: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set.

Objective/hypothesis: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS) current densities on corticospinal excitability.

Methods: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs) of 0.013, 0.029, 0.058 and 0.083 mA/cm(2) were applied on twelve right-handed (mean age 34.5±10.32 yrs) healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2) respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR) was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter.

Results: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2) and 0.029 mA/cm(2) (P = 0.003). There were no significant differences between excitability changes for the 0.013 mA/cm(2) and 0.058 mA/cm(2) (P = 0.080) or 0.013 mA/cm(2) and 0.083 mA/cm(2) (P = 0.484) conditions.

Conclusion: This study found that a-tDCS with a current density of 0.013 mA/cm(2) induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2). The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

Show MeSH
Related in: MedlinePlus