Department of Psychology, UiT The Arctic University of Norway, Tromsø, Norway.
Department of Psychology, UiT The Arctic University of Norway, Tromsø, Norway.
J Affect Disord. 2018 Jul;234:164-173. doi: 10.1016/j.jad.2018.02.077. Epub 2018 Feb 28.
Transcranial direct current stimulation (tDCS) above the left dorsolateral prefrontal cortex (lDLPFC) has been widely used to improve symptoms of major depressive disorder (MDD). However, the effects of different stimulation protocols in the entire frontal lobe have not been investigated in a large sample including patient data.
We used 38 head models created from structural magnetic resonance imaging data of 19 healthy adults and 19 MDD patients and applied computational modeling to simulate the spatial distribution of tDCS-induced electric fields (EFs) in 20 frontal regions. We evaluated effects of seven bipolar and two multi-electrode 4 × 1 tDCS protocols.
For bipolar montages, EFs were of comparable strength in the lDLPFC and in the medial prefrontal cortex (MPFC). Depending on stimulation parameters, EF cortical maps varied to a considerable degree, but were found to be similar in controls and patients. 4 × 1 montages produced more localized, albeit weaker effects.
White matter anisotropy was not modeled. The relationship between EF strength and clinical response to tDCS could not be evaluated.
In addition to lDLPFC stimulation, excitability changes in the MPFC should also be considered as a potential mechanism underlying clinical efficacy of bipolar montages. MDD-associated anatomical variations are not likely to substantially influence current flow. Individual modeling of tDCS protocols can substantially improve cortical targeting. We make recommendations for future research to explicitly test the contribution of lDLPFC vs. MPFC stimulation to therapeutic outcomes of tDCS in this disorder.
经颅直流电刺激（tDCS）作用于左侧背外侧前额叶皮层（lDLPFC）已被广泛用于改善重度抑郁症（MDD）的症状。然而，在包括患者数据的大样本中，尚未研究整个前额叶内不同刺激方案的效果。
我们使用了 19 名健康成年人和 19 名 MDD 患者的结构磁共振成像数据创建的 38 个头部模型，并应用计算建模来模拟 20 个额区 tDCS 诱导电场（EF）的空间分布。我们评估了七种双极和两种四电极 4×1 tDCS 方案的效果。
对于双极刺激模式，lDLPFC 和内侧前额叶皮层（MPFC）中的 EF 强度相当。根据刺激参数的不同，EF 皮质图的变化程度相当大，但在对照组和患者中发现它们相似。4×1 刺激模式产生了更局部的但强度较弱的效果。
未对脑白质各向异性进行建模。无法评估 EF 强度与 tDCS 临床反应之间的关系。
除了 lDLPFC 刺激外，MPFC 的兴奋性变化也应被视为双极刺激模式临床疗效的潜在机制。MDD 相关的解剖学变化不太可能对电流流动产生重大影响。tDCS 方案的个体建模可以显著提高皮质靶向性。我们提出了未来研究的建议，以明确测试 lDLPFC 与 MPFC 刺激对 tDCS 治疗该疾病疗效的贡献。
