File:General paradigm of BCIs. Sensors collected neural activities, and signals are processed by the decoders to control external devices, which also return feedback to the individual.jpg

English: Brain–computer interfaces (BCIs) provide a way for paralyzed patients to interact with external devices or restore sensory and motor function by translating neural activities obtained from the brain into control commands [1–5]. The BCI system consists of sensors, decoders, and effectors. Depending on the signal recording electrodes, there are mainly 3 types of BCIs: noninvasive, semi-invasive, and invasive BCIs. The paradigm of BCIs is shown in Fig. 1. In general, the sensors or electrodes record the neural activity, and the obtained brain signals are collected by the acquisition system, and then designed algorithms (decoders) are applied to extract features or patterns of specific signals, which will be translated into command instructions. Finally, the external device (the effectors) executes the task according to the instruction and feedback to the individuals.