本文综述了在系统层面研究大脑内部活动最先进的技术。负责我们日常生活的神经活动是由大脑不同区域复杂的协调过程共同完成的。表面上，不同功能由具体的解剖结构所控制，然而事实上是通过内部大量相互连接的神经元和突触通路的动态网络来实现的。因此，从系统层面能更好地理解大脑的正常生理或病理状态。目前已有很多神经工程技术，但本文将重点关注三个领域：神经成像、神经接口和神经调控技术。神经成像能够帮助我们描绘大脑的结构和功能，这对理解正常和疾病状态下的神经系统功能至关重要。基于神经影像的知识，可以开发神经接口与神经系统进行交流，或者调控大脑的活动。这三个领域的研究对开发相关的仪器、设备及其应用很关键。在神经反馈的基础上，通过神经接口 (侵入式或非侵入式) 监测神经活动 (通过神经影像模式)，以一定的刺激参数，调控和改变神经功能。总之，系统神经工程是指利用工程工具和技术来成像、解码和调控大脑，进一步理解大脑的正常功能及障碍修复。这些领域之间的相互交叉将引领系统神经工程的发展方向——发展神经技术，来增强对大脑整体功能和功能障碍的理解，以及对神经和精神障碍的干预。

In this paper, we review the current state-of-the-art techniques used for understanding the inner workings of the brain at a systems level. The neural activity that governs our everyday lives involves an intricate coordination of many processes that can be attributed to a variety of brain regions. On the surface, many of these functions can appear to be controlled by specific anatomical structures; however, in reality, numerous dynamic networks within the brain contribute to its function through an interconnected web of neuronal and synaptic pathways. The brain, in its healthy or pathological state, can therefore be best understood by taking a systems-level approach. While numerous neuroengineering technologies exist, we focus here on three major thrusts in the field of systems neuroengineering: neuroimaging, neural interfacing, and neuromodulation. Neuroimaging enables us to delineate the structural and functional organization of the brain, which is key in understanding how the neural system functions in both normal and disease states. Based on such knowledge, devices can be used either to communicate with the neural system, as in neural interface systems, or to modulate brain activity, as in neuromodulation systems. The consideration of these three fields is key to the development and application of neuro-devices. Feedback-based neuro-devices require the ability to sense neural activity (via a neuroimaging modality) through a neural interface (invasive or noninvasive) and ultimately to select a set of stimulation parameters in order to alter neural function via a neuromodulation modality. Systems neuroengineering refers to the use of engineering tools and technologies to image, decode, and modulate the brain in order to comprehend its functions and to repair its dysfunction. Interactions between these fields will help to shape the future of systems neuroengineering—to develop neurotechniques for enhancing the understanding of whole-brain function and dysfunction, and the management of neurological and mental disorders.