Influence of gender-related differences in transcranial direct current stimulation: A Computational Study*

Gender-related anatomical differences have been reported with respect to brain and cerebrospinal fluid. The cortical induced electric field (EF) in transcranial direct current stimulation (tDCS) depends both on the dose (electrode montage and applied current) and the individual anatomical details. Therefore in spite of fixed dose, one can expect gender-related differences to impact induced EF which in turn would influence tDCS outcome. The abundance of promise with tDCS in both research and clinical domains is also accompanied with variability in response. The in-constant induced cortical EF is one of the main contributors of this variability.The aim of this study is to quantify the effects of the gender-related morphological changes on tDCS induced cortical EF. MRI data were obtained for 10 healthy individuals (5 males: M1–M5 and 5 females: F1-F5) spanning ages 27-47 years. Finite element models derived from the individual MRI and simulating the classic left motor cortex–contralateral supraorbital (C3-SO) montage were used to predict the cortical EF. The percentage tissue volume were also determined to illustrate anatomical differences in the dataset considered.Findings indicate that induced EF is higher in female head models on an average than male head models across several metrics. While the average peak EF value in female head models was comparable to that of male head models, the mean and median values were 11.6% and 10% higher. On an individual basis, the highest peak value was observed in a female subject F3 (0.83 V/m) while the lowest peak value was observed in male subject M2 (0.34 V/m) -indicating a variation of ~2.4-fold across the dataset considered. The average gray matter percentage volume in females was 11.6% higher than in males. The average white matter percentage volume was 8.7% higher in females while negligible CSF percentage volume difference was noted across gender. The results of our study indicate gender-related differences in tDCS induced current flow and quantify the extent of this variation.

[1]  M. Nitsche,et al.  Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation , 2000, The Journal of physiology.

[2]  Abhishek Datta,et al.  Effect of Aging on Cortical Current Flow Due to Transcranial Direct Current Stimulation: Considerations for Safety , 2018, 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC).

[3]  Walter Paulus,et al.  Gender-specific modulation of short-term neuroplasticity in the visual cortex induced by transcranial direct current stimulation , 2008, Visual Neuroscience.

[4]  Abhishek Datta,et al.  Guidelines for precise and accurate computational models of tDCS , 2012, Brain Stimulation.

[5]  Sarah H. Lisanby,et al.  Fundamentals of transcranial electric and magnetic stimulation dose: Definition, selection, and reporting practices , 2012, Brain Stimulation.

[6]  Efstathios D. Gennatas,et al.  Age-Related Effects and Sex Differences in Gray Matter Density, Volume, Mass, and Cortical Thickness from Childhood to Young Adulthood , 2017, The Journal of Neuroscience.

[7]  Andrew K. Martin,et al.  Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on “Mind-Reading” , 2017, Neuroscience.

[8]  R. Gur,et al.  Complementarity of sex differences in brain and behavior: From laterality to multimodal neuroimaging , 2017, Journal of neuroscience research.

[9]  N Lynnerup,et al.  Cranial thickness in relation to age, sex and general body build in a Danish forensic sample. , 2001, Forensic science international.

[10]  S. Rossi,et al.  Evidence-based guidelines on the therapeutic use of transcranial direct current stimulation (tDCS) , 2017, Clinical Neurophysiology.

[11]  L. Parra,et al.  Inter-Individual Variation during Transcranial Direct Current Stimulation and Normalization of Dose Using MRI-Derived Computational Models , 2012, Front. Psychiatry.

[12]  Q. Wang,et al.  Gender Differences in Current Received during Transcranial Electrical Stimulation , 2014, Front. Psychiatry.

[13]  Timothy J. Herron,et al.  Sex differences in cortical and subcortical human brain anatomy , 2015 .

[14]  G. Rippon.  Sex differences in cortical and subcortical human brain anatomy , 2019 .

[15]  Paul M. Thompson,et al.  Why size matters: Differences in brain volume account for apparent sex differences in callosal anatomy The sexual dimorphism of the corpus callosum , 2014, NeuroImage.

[16]  B. Turetsky,et al.  Sex Differences in Brain Gray and White Matter in Healthy Young Adults: Correlations with Cognitive Performance , 1999, The Journal of Neuroscience.

[17]  Mark S. George,et al.  Evidence of transcranial direct current stimulation-generated electric fields at subthalamic level in human brain in vivo , 2018, Brain Stimulation.

[18]  Shu Chen,et al.  Does Gender Make a Difference in Deception? The Effect of Transcranial Direct Current Stimulation Over Dorsolateral Prefrontal Cortex , 2018, Front. Psychol..