Intracranial EEG Recordings of High-Frequency Activity From a Wireless Implantable BMI Device in Awake Nonhuman Primates.

Objective: Wireless implantable brain machine interfaces (BMIs) are a promising tool to restore communication and motor functions for individuals with severe motor disability. Prior to clinical application, recording performance must be sufficiently confirmed by animal experiments. In this paper, we aimed to evaluate the performance of a novel BMI wireless device for recording brain activity in two nonhuman primates.

Method: We customized a wireless device for implantable BMIs for clinical application. We used a battery instead of a wireless power charging system. Thirty-two electrodes were subdurally implanted over the left temporoparietal cortex. We evaluated the recording performance of the wireless device by auditory steady-state responses (ASSRs) and ketamine-induced responses.

Result: The devices successfully recorded broadband oscillatory activities up to the high-frequency band from the temporal cortex in two awake macaque monkeys. Spectral analysis of raw signals demonstrated that the devices detected characteristic results of a 40-Hz ASSR and prominent high-frequency band activity induced by ketamine injection.

Conclusion: We confirmed the functionality of the wireless device in recording and transmitting electrocorticography (ECoG) signals with both millisecond precision and recording stability.

Significance: These results provide confidence that this wireless device can be a translational tool for other fundamental neuroscientific studies in free-moving models.