Fig. 1 | Nature Communications

Fig. 1

From: Bypassing stroke-damaged neural pathways via a neural interface induces targeted cortical adaptation

Fig. 1

Volitional control of a paralysed hand via an artificial cortico-muscular connection. a Each monkey controlled the position of a cursor (blue square) using wrist torque or hand position to acquired targets (red square) displayed on the screen. An artificial cortico-muscular connection (ACMC) was achieved by converting cortical oscillatory activity in real time to electrical stimulation of paralysed muscles. b A example of five successful trials from a torque-tracking task when the ACMC was on (green) and one catch trial when the ACMC was switched off (grey shading) in Monkey TA. Extensor and centre wrist torque targets (blue shading) were presented on the screen. The input microelectrode was located in the hand area of the primary motor cortex (M1), and electrical stimuli were applied to the extensor carpi radialis (ECR) and extensor digitorum communis (EDC) muscle pair. A raw signal (1st row) was recorded from the electrode in M1 and filtered in the high-gamma frequency band (2nd row). The blue vertical lines in the 1st and 2nd rows indicate the timing of electrical stimulation. An arbitrary one-cycle high-gamma waveform was selected (3rd row) from the high-gamma oscillations as the input signal for controlling the ACMC. The red traces in the 3rd row indicate the high-gamma waveforms detected by the template-matching method, with the thresholds represented as blue lines in the 3rd row. The yellow lines with 10 yellow dots in the 3rd row represent the template for high-gamma waveform detection. The 4th row indicates the frequencies of the detected high-gamma waveforms. Electrical stimulation was delivered to the paralysed ECR and EDC muscles with a current (5th trace) and frequency (6th trace) that were proportional to the moving averaged frequencies (250-ms time window) of the detected high-gamma waveforms above a stimulation threshold (blue line in the 4th trace). The blue rectangles in the wrist torque trace in the 7th row represent the extensor and centre wrist torque targets. The arrows at the bottom indicate successful trial completion and reward times. Similar results were obtained from independent experiments (N = 3 monkeys, n = 108 sessions)

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