Autonomous control for mechanically stable navigation of microscale implants in brain tissue to record neural activity

作者：Anand Sindhu; Kumar Swathy Sampath; Muthuswamy Jit^*

来源：Biomedical Microdevices, 2016, 18(4): 72.

DOI：10.1007/s10544-016-0093-8

• Microdrive
• Neural implants
• Neural interfaces
• Prostheses
• Robot
• Soft tissue
• Probes

Emerging neural prosthetics require precise positional tuning and stable interfaces with single neurons for optimal function over a lifetime. In this study, we report an autonomous control to precisely navigate microscale electrodes in soft, viscoelastic brain tissue without visual feedback. The autonomous control optimizes signal-to-noise ratio (SNR) of single neuronal recordings in viscoelastic brain tissue while maintaining quasi-static mechanical stress conditions to improve stability of the implant-tissue interface. Force-displacement curves from microelectrodes in in vivo rodent experiments are used to estimate viscoelastic parameters of the brain. Using a combination of computational models and experiments, we determined an optimal movement for the microelectrodes with bidirectional displacements of 3: 2 ratio between forward and backward displacements and a inter-movement interval of 40 s for minimizing mechanical stress in the surrounding brain tissue. A regulator with the above optimal bidirectional motion for the microelectrodes in in vivo experiments resulted in significant reduction in the number of microelectrode movements (0.23 movements/min) and longer periods of stable SNR (53% of the time) compared to a regulator using a conventional linear, unidirectional microelectrode movement (with 1.48 movements/ min and stable SNR 23 % of the time).

• 出版日期2016-8