Figure 5—figure supplement 1. | High performance communication by people with paralysis using an intracortical brain-computer interface

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High performance communication by people with paralysis using an intracortical brain-computer interface

Figure 5—figure supplement 1.

Affiliation details

Stanford University, United States; Emory University and Georgia Institute of Technology, United States; Emory University, United States; Massachusetts General Hospital, United States; Brown University, United States; Rehabilitation R&D Service, Department of VA Medical Center, United States; Case Western Reserve University, United States; Louis Stokes VA Medical Center, United States; Harvard Medical School, United States
Figure 5—figure supplement 1.
Download figureOpen in new tabFigure 5—figure supplement 1. HF-LFP signals have similar time course and condition dependence to spiking activity.

Control algorithms for T6 incorporated high-frequency LFP power signals (HF-LFP; see Materials and methods). A potential concern with a power signal is that it may pick up artifacts related to EMG from eye movements. Here we analyze activity during a decoder calibration block to show that HF-LFP signals have a strikingly similar time course and condition dependence as spiking activity. (a) Sample of the signals recorded on T6’s array during a decoder calibration block. Some channels show discernible single or multiunit activity (threshold crossings), while others do not. Neural data was processed as in Figure 5, with thresholds set to −4 times the r.m.s. voltage value for each channel. Scale bars (lower left corner) represent 150 µV (vertical) and 0.5 milliseconds (horizontal). (b) Target positions and corresponding colors used to label each condition in the subsequent panels. (c) Threshold crossing rates as a function of time for each condition (movement to a given target location), beginning at the time of target onset, for five example channels with discernable threshold crossing activity. Each trace represents the mean ± s.e.m. threshold crossing rate for a given condition, computed across seven trials for each condition. Horizontal scale bar represents 100 ms, vertical scale bar represents 40 threshold crossings / sec. Traces from individual trials were smoothed by convolving with a Gaussian kernel with 50 ms s.d. prior to mean / standard deviation calculations. (d) Same plots, but depicting HF-LFP power instead of threshold crossing rates, for a different set of example channels that did not have discernible multiunit activity. Horizontal scale bar is again 100 ms, vertical scale (HF-LFP power) is in arbitrary units. The same trials as panel (c) above were used. As shown, HF-LFP power signals display a similar time course following target onset, as well as degree of condition dependence, as threshold crossing activity. Data are from T6’s post-implant day 570.