The Neurobiological Effects of Electroconvulsive Therapy Studied Through Magnetic Resonance: What Have We Learned, and Where Do We Go?

Electroconvulsive Therapy (ECT) is an established treatment choice for severe, treatment-resistant depression, yet its mechanisms of action remain elusive. Magnetic resonance imaging (MRI) of the human brain before and after treatment, has been crucial to aid our comprehension of the ECT neurobiological effects. However, to date the majority of MRI studies have been underpowered, used heterogeneous patient samples as well as different methodological approaches, altogether causing mixed results and poor clinical translation. Hence, an association between MRI markers and therapeutic response remains to be established. Recently, the availability of large datasets through a global collaboration has provided the statistical power needed to characterize whole-brain structural and functional brain changes following ECT. In addition, MRI technological developments allow new aspects of brain function and structure to be investigated. Finally, more recent studies have also investigated immediate and long-term effects of ECT, which may aid in the separation of the therapeutically relevant effects from epiphenomena. The goal of the present review is to outline MRI studies (T1, Diffusion-weighted imaging, 1-Hydrogen Magnetic Resonance Spectroscopy) of ECT in depression, to advance our understanding of the ECT neurobiological effects. Based on the reviewed literature, we suggest a model whereby the neurobiological effects can be understood within a framework of disruption, neuroplasticity and rewiring of neural circuits. An improved characterization of the neurobiological effects of ECT may increase our understanding of ECT´s therapeutic effects, ultimately leading to improved patient care.

电休克疗法（ECT）是治疗严重的、难治性抑郁症的一种既定治疗选择，但其作用机制仍不明确。治疗前后对人脑进行磁共振成像（MRI），对于帮助我们理解ECT的神经生物学效应至关重要。然而，迄今为止，大多数MRI研究样本量不足，使用的患者样本具有异质性，且采用了不同的方法学，这些因素共同导致研究结果参差不齐，临床转化效果不佳。因此，MRI标志物与治疗反应之间的关联仍有待确定。最近，通过全球合作获得的大量数据集提供了统计效力，得以描绘ECT治疗后全脑结构和功能的变化。此外，MRI技术的发展使研究大脑功能和结构的新方面成为可能。最后，最新的研究还对ECT的即时和长期效应进行了探究，这可能有助于将与治疗相关的效应与附带现象区分开来。本综述旨在概述针对抑郁症患者ECT治疗的MRI研究（T1成像、弥散加权成像、氢质子磁共振波谱），以增进我们对ECT神经生物学效应的理解。基于所回顾的文献，我们提出一个模型，在该模型中，可从神经回路的破坏、神经可塑性和重新连接的框架内理解神经生物学效应。更好地描述ECT的神经生物学效应，可能会加深我们对ECT治疗效果的理解，最终改善患者护理。