Transkraniyal Doğru Akım Stimülasyonu (tDCS) ile İndüklenen Nöroplastisitenin Diskalkulili Bireylerde Sayısal Biliş ve Fronto-Parietal Ağ Bağlantısallığı Üzerindeki Etkileri

Abstract

Bu çalışmanın amacı, transkraniyal doğru akım stimülasyonu (tDCS) yoluyla indüklenen nöroplastisite süreçlerinin, diskalkulili bireylerde sayısal biliş ve fronto-parietal ağ bağlantısallığı üzerindeki etkilerini inceleyen güncel bulguları değerlendirmektir. Diskalkuli, matematiksel işlemlerde kalıcı güçlüklerle seyreden nörogelişimsel bir bozukluk olup parietal ve frontal kortekslerdeki yapısal ve işlevsel farklılıklarla ilişkilendirilmektedir. Son yıllarda, non-invaziv beyin uyarım tekniklerinden biri olan tDCS’nin bu ağlardaki nöronal iletişimi güçlendirerek bilişsel performansı artırabileceği ileri sürülmüştür. Bu bağlamda, 2010–2024 yılları arasında yayımlanan hakemli dergilerdeki deneysel ve nörogörüntüleme temelli çalışmalar sistematik olarak incelenmiştir. Bulgular, özellikle sol parietal bölgeye uygulanan anodal tDCS’nin sayı karşılaştırma, aritmetik işlemleme ve sembolik öğrenme performansını anlamlı düzeyde artırabildiğini göstermektedir. Ayrıca fMRI ve MRS çalışmalarında, tDCS sonrası fronto-parietal bağlantısallığın güçlendiği, GABA konsantrasyonunun azaldığı ve glutamaterjik aktivitenin arttığı rapor edilmiştir.Bu bağlamda tDCS’nin diskalkulide nöroplastisiteyi destekleyici, öğrenme temelli terapötik bir araç olabileceği ancak standart protokollerin ve uzun süreli takip çalışmalarının gerekliliği ortaya konmuştur.

Keywords

• Diskalkuli
• tDCS
• Nöroplastisite
• Sayısal Biliş
• Fronto-Parietal Ağ
• Nöromodülasyon

The Effects of Transcranial Direct Current Stimulation (tDCS)-Induced Neuroplasticity on Numerical Cognition and Fronto-Parietal Network Connectivity in Individuals with Dyscalculia

Abstract

The aim of this review study is to evaluate current findings on the effects of neuroplasticity processes induced by transcranial direct current stimulation (tDCS) on numerical cognition and fronto-parietal network connectivity in individuals with dyscalculia. Dyscalculia is a neurodevelopmental disorder characterized by persistent difficulties in mathematical operations and is associated with structural and functional differences in the parietal and frontal cortices. In recent years, it has been suggested that tDCS, a non-invasive brain stimulation technique, may enhance cognitive performance by strengthening neuronal communication within these networks. In this context, experimental and neuroimaging-based studies published in peer-reviewed journals between 2010 and 2024 were systematically examined. Findings indicate that anodal tDCS applied to the left parietal region significantly improves performance in number comparison, arithmetic processing, and symbolic learning tasks. Moreover, fMRI and MRS studies have reported enhanced fronto-parietal connectivity, decreased GABA concentration, and increased glutamatergic activity following tDCS. in this context,tDCS appears to be a promising neuromodulatory tool that supports neuroplasticity and learning-based therapeutic interventions in dyscalculia; however, standardized protocols and long-term follow-up studies are required to validate its efficacy.

Keywords

• Dyscalculia
• tDCS
• Neuroplasticity
• Numerical Cognition
• Fronto-Parietal Network
• Neuromodulation

References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: American Psychiatric Publishing.
2. Amerikan Psikiyatri Birliği. (2014). Ruhsal bozuklukların tanısal ve istatistiksel el kitabı (DSM-5) (E. Köroğlu, Çev.). Ankara: Hekimler Yayın Birliği.
3. Antal, A., Alekseichuk, I., Bikson, M., Brockmöller, J., Brunoni, A. R., Chen, R., … Paulus, W. (2017). Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Clinical Neurophysiology, 128(9), 1774–1809. https://doi.org/10.1016/j.clinph.2017.06.001
4. Berryhill, M. E., & Jones, K. T. (2012). tDCS selectively improves working memory in older adults with more education. Neuroscience Letters, 521(2), 148–151. https://doi.org/10.1016/j.neulet.2012.05.074
5. Bikson, M., Grossman, P., Thomas, C., Zannou, A. L., Jiang, J., Adnan, T., … Edwards, D. (2016). Safety of transcranial direct current stimulation: Evidence-based update 2016. Brain Stimulation, 9(5), 641–661. https://doi.org/10.1016/j.brs.2016.06.004
6. Bugden, S., & Ansari, D. (2021). How to close the gap? The role of working memory in numerical cognition. Trends in Cognitive Sciences, 25(4), 280–292.
7. Butterworth, B. (2019). Dyscalculia: From brain to education. London: Routledge.
8. Casey, B. J., Tottenham, N., Liston, C., & Durston, S. (2005). Imaging the developing brain: What have we learned about cognitive development? Trends in Cognitive Sciences, 9(3), 104–110.

9. Clark, V. P., Coffman, B. A., Mayer, A. R., Weisend, M. P., Lane, T. D. R., Calhoun, V. D., … Wassermann, E. M. (2011). tDCS guided using fMRI significantly accelerates learning to identify concealed objects. NeuroImage, 59(1), 117–128.
10. Cohen Kadosh, R., & Walsh, V. (2009). Numerical representation in the parietal lobes: Abstract or not abstract? Behavioral and Brain Sciences, 32(3–4), 313–328.
11. Cohen Kadosh, R., Soskic, S., Iuculano, T., Kanai, R., & Walsh, V. (2010). Modulating neuronal activity produces specific and long-lasting changes in numerical competence. Current Biology, 20(22), 2016–2020.
12. Cohen Kadosh, R., Levy, N., O’Shea, J., Shea, N., & Savulescu, J. (2012). The neuroethics of non-invasive brain stimulation. Current Biology, 22(4), R108–R111.
13. Dehaene, S., & Cohen, L. (1997). Cerebral pathways for calculation: Double dissociation between rote verbal and quantitative knowledge of arithmetic. Cortex, 33(2), 219–250.
14. Dehaene, S., Piazza, M., Pinel, P., & Cohen, L. (2003). Three parietal circuits for number processing. Cognitive Neuropsychology, 20(3–6), 487–506.
15. Dedoncker, J., Brunoni, A. R., Baeken, C., & Vanderhasselt, M. A. (2016). A systematic review and meta-analysis of the effects of transcranial direct current stimulation over the dorsolateral prefrontal cortex. Brain Stimulation, 9(4), 501–517.
16. Dockery, C. A., Hueckel-Weng, R., Birbaumer, N., & Plewnia, C. (2009). Enhancement of planning ability by transcranial direct current stimulation. Journal of Neuroscience, 29(22), 7271–7277.
17. Fertonani, A., & Miniussi, C. (2017). Transcranial electrical stimulation: What we know and do not know about mechanisms. Neuroscientist, 23(2), 109–123.
18. Fregni, F., Boggio, P. S., Nitsche, M. A., Bermpohl, F., Antal, A., Feredoes, E., … Pascual-Leone, A. (2005). Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory. Experimental Brain Research, 166(1), 23–30.
19. Fritsch, B., Reis, J., Martinowich, K., Schambra, H. M., Ji, Y., Cohen, L. G., & Lu, B. (2010). Direct current stimulation promotes BDNF-dependent synaptic plasticity. Neuron, 66(2), 198–204.
20. Hebb, D. O. (1949). The organization of behavior: A neuropsychological theory. New York, NY: Wiley.
21. Kolb, B., & Gibb, R. (2014). Searching for the principles of brain plasticity and behavior. Cortex, 58, 251–260.
22. Menon, V. (2016). Memory and cognitive control circuits in mathematical cognition and learning. Progress in Brain Research, 227, 159–186.
23. Nitsche, M. A., & Paulus, W. (2000). Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. Journal of Physiology, 527(3), 633–639.
24. Reis, J., Schambra, H. M., Cohen, L. G., Buch, E. R., Fritsch, B., Zarahn, E., … Krakauer, J. W. (2009). Noninvasive cortical stimulation enhances motor skill acquisition. Proceedings of the National Academy of Sciences, 106(5), 1590–1595.
25. Stagg, C. J., & Nitsche, M. A. (2011). Physiological basis of transcranial direct current stimulation. Neuroscientist, 17(1), 37–53.