Fig. 3: i2CS elicits distinct experimental nerve and organ responses that are different than those to equivalent, non-interfering sinusoidal current stimulation. | Nature Communications

Fig. 3: i2CS elicits distinct experimental nerve and organ responses that are different than those to equivalent, non-interfering sinusoidal current stimulation.

From: Control of spatiotemporal activation of organ-specific fibers in the swine vagus nerve by intermittent interferential current stimulation

Fig. 3

A Schematic cross section of the stimulated VN of the example animal from Fig. 2 at the level of an implanted MCE; shown are outlines of nerve fascicles and the 2 contacts (grey bars) used for i2CS, with the left source at greater amplitude than the right source (negative steering ratio, expressed as the ratio in amplitude of the left current source with respect to the total current, mapped to a −1 to +1 range for illustration purposes; i.e., 0.9 = −1, 0.7 = −0.5, 0.5 = 0, 0.3 = 0.5, 0.1 = 1. −1 denotes 90% of the total amplitude on the left contact and 10% of the total amplitude on the right contact; red arrow on left side of x-axis); left and right sources have carrier frequencies of 20 kHz and 22 kHz respectively. The colormap represents the maximum peak-to-peak amplitude of the beat interference envelope, indicating the location of the maximal amplitude modulation (cf. Suppl. Fig. S1). A1 Evoked compound action potential (eCAP) triggered from the onset of i2CS, with 0.75 mA total current delivered through the 2 sources; slow and fast eCAP components are identified by the shaded areas corresponding to time windows defined by the average conduction velocities for ‘slow’ and ‘fast’ fibers. A2 Weak laryngeal EMG in response to i2CS. A3 Robust breathing response (blue trace: raw respiratory movements, orange trace: respective breathing interval), during a 20s-long train of i2CS (black trace). B Same as in A, but for i2CS steered in the opposite direction (i.e., towards the right side; shown are sizeable eCAP and EMG responses, with minimal breathing response. C Same as in A, but for sinusoidal stimulation. The two current sources have the same carrier frequency (20 kHz). The strength of the electric potential generated by this particular current steering ratio is represented by a colormap. Robust fast eCAP and EMG, as well as intense breathing response. D Same as in C, but for the opposite steering direction. All eCAP and EMG responses shown as averages triggered from n = 660 stimuli.

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