Shanechi Maryam M
Annu Int Conf IEEE Eng Med Biol Soc. 2016 Aug;2016:1766-1769. doi: 10.1109/EMBC.2016.7591059.
Identification of input-output (IO) dynamics of brain networks in response to electrical stimulation is essential for devising closed-loop therapies for neurological disorders such as major depression. A critical component for accurate IO identification is the stimulation input design. The time available for open-loop stimulation to perform system identification is typically limited. While our prior design of a binary noise (BN) modulated input pattern satisfies the requirements for optimal identification and clinical safety, it does not incorporate any prior information about the underlying network. When the identification time is constrained, BN identification performance may be improved by incorporating such information. Here we design a generalized binary noise (GBN) modulated stimulation pattern that achieves time-efficient identification of IO dynamics by utilizing the time-constant information of the network. To test GBN's performance, we implemented a closed-loop controller within a clinical stimulation system. We used our closed-loop system to control mood symptoms in depression using simulated neural activity under linear network dynamics. With a short identification time (20 mins), the controller derived from GBN identification performed as well as an ideal controller that had full knowledge of the network model, and better than a controller derived from BN identification. Our results have important implications for optimal system identification and closed-loop control of brain network dynamics.
识别大脑网络对电刺激的输入-输出(IO)动态特性对于设计针对重度抑郁症等神经系统疾病的闭环疗法至关重要。准确进行IO识别的一个关键要素是刺激输入设计。用于开环刺激以进行系统识别的可用时间通常有限。虽然我们之前设计的二元噪声(BN)调制输入模式满足了最优识别和临床安全性的要求,但它没有纳入关于基础网络的任何先验信息。当识别时间受到限制时,通过纳入此类信息可能会提高BN的识别性能。在此,我们设计了一种广义二元噪声(GBN)调制刺激模式,通过利用网络的时间常数信息实现对IO动态特性的高效识别。为了测试GBN的性能,我们在临床刺激系统中实现了一个闭环控制器。我们使用我们的闭环系统,在线性网络动态特性下利用模拟神经活动来控制抑郁症中的情绪症状。在较短的识别时间(20分钟)内,源自GBN识别的控制器表现与完全了解网络模型的理想控制器相当,且优于源自BN识别的控制器。我们的结果对于大脑网络动态特性的最优系统识别和闭环控制具有重要意义。