Dorsolateral Prefrontal Korteksin Modüle Edilmiş Anodal Akım İle Uyarımının Çalışma Belleği Üzerine Etkisinin İncelenmesi: Ön çalışma

Year 2025, Volume: 15 Issue: 3, 269 - 275, 31.12.2025

Zeynep Küçük , Ezgi Tuna Erdoğan , Adnan Kurt , Sacit Karamursel

https://doi.org/10.26650/experimed.1784343

https://izlik.org/JA67JD48WX

Abstract

Amaçlar:
Çalışma belleğinin iki bileşeni vardır: geçici depolama ve bilişsel davranış için gerekli bilgilerin merkezi yürütücü sistem aracılığıyla işlenmesi. Bu çalışma, dorsolateral prefrontal kortekse uygulanan modüle edilmiş anodal transkraniyal doğru akım uyarımının (mtDCS) çalışma belleği üzerindeki etkilerini araştırmayı amaçlamıştır.

Yöntem:
Nörolojik veya psikiyatrik ilaç kullanımı ve tanısı olmayan 12 gönüllü bu çalışmaya katılmıştır. Çalışma belleği performansını ölçmek için, uyarım sırasında ünsüz harflerden oluşan 3-geri bellek testinin görsel versiyonu uygulanmıştır. Değerlendirmenin başında, öğrenmeyi etkisini ortadan kaldırmak amacıyla katılımcılara 20 dakikalık deneme seti uygulanmıştır. Katılımcılar başarı düzeyinde %50’ye ulaştıklarında, dört set uyarım uygulanmıştır. Uyarım setlerinin toplam süresi 10 dakikadır. Uyarım setleri şu koşulları içermektedir: modüle edilmiş akım (11 Hz ve 22 Hz) 1.70 miliamper (mA) offset ve 0.35 mA tepe-tepe akım, sabit akım (DC) koşulunda 2 mA offset ve yalancı (sham) uyarım. 3-geri bellek görevleri sırasında katılımcıların tepki süreleri ve toplam doğru cevapları kaydedilmiştir.

Bulgular:
3-geri testinden alınan doğru yanıt ortalamları uyarım koşulları arasında farklılık göstermektedir (χ²(3) = 9.00, p = .029). Sol DLPFC uyarımı, mtDCS ve tDCS koşulları arasındaki ortalama doğru yanıt sayılarında anlamlı bir fark ortaya koymuştur; ancak post-hoc analiz sonucunda bu fark sham koşulla karşılaştırıldığında anlamlı bulunmamıştır. 11 Hz ve 22 Hz mtDCS koşullarında ortalama doğru yanıt sayısı, DC stimülasyona kıyasla anlamlı derecede daha düşük bulunmuştur (Z = -2.56, p <0.017); özellikle 11 Hz mtDCS koşulunun etkisi daha belirgindir.
Sonuç:
Alfa bandındaki 11 Hz uyarımı, çalışma belleği üzerinde baskılayıcı bir etki göstermiş olabilir. Gelecek çalışmalarda örneklem sayısı artırılarak farklı frekanslardaki uyarım etkileri incelenmelidir.

Keywords

working memory , tDCS , mtDCS , neuromodulation

Effect of Modulated Anodal Stimulation over the Dorsolateral Prefrontal Cortex on Working Memory: A Preliminary Study

https://izlik.org/JA67JD48WX

Abstract

Objectives: Working memory has two components: temporary storage and manipulation of the informa tion necessary for cognitive behavior through the central executive system. This study aimed to investigate the effects of modulated anodal transcranial direct current stimulation (mtDCS) of the dorsolateral prefrontal cortex on working memory.
Materials and Methods: Twelve volunteers without neurological or psychiatric disorders and without drug use participated. Working memory performance was assessed with a visual 3back task using consonant letters during stimulation. A 20minute training session was conducted to facilitate learning, and participants who achieved an accuracy rate of 50% or higher proceeded to the main experiment. Four stimulation conditions were applied, each lasting 10 minutes: mtDCS11 Hz and mtDCS22 Hz (1.70 mA offset, 0.35 mA peaktopeak), direct current (DC) (2 mA), and sham. Reaction times and total correct responses were recorded.
Results: Statistical analysis of the left dorsolateral prefrontal cortex (DLPFC) stimulation revealed a significant difference in the mean numbers of correct responses among the mtDCS and transcranial direct current stimulation (tDCS) conditions, but not compared with sham. The mean number of correct responses under mtDCS11Hz and mtDCS22Hz was significantly lower than under DC stimulation; however the performance decrement under 11 Hz mtDCS was the most pronounced among the active conditions.
Conclusion: mtDCS11Hz and mtDCS22Hz negated the subtle facilitation of tDCS might have provided.

Keywords

Working memory , Transcranial direct current stimulation , Electric stimulation therapy

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