Bnc 2110

Two electrodes connected the two electrolyte chambers to an amplifier (Axopatch 200B, Molecular Devices), which applied voltage to the electrodes and recorded the resulting current signal from the system. The current signal was processed with a digitizer (Digidata 1440A, Molecular Devices) for the pore conductance tests (Figure 2d) or using a data acquisition board (BNC-2110, National Instrument) with a PCI card (PCI 6259, National Instrument). The data acquisition board was used for recapture experiments since the board allowed us to modulate the polarity of the applied voltage using LabVIEW script. The current data was acquired at 30 kHz sampling frequency and filtered by a 2 kHz Bessel filter. The recorded data was analyzed using a custom-made MATLAB (MathWorks, MA) code. The function of the 2 kHz Bessel filter was to achieve a higher signal-to-noise ratio, which also facilitated the detection of resistive pulses in the measured signal without any loss.

Recordings were obtained using an Axon-patch 200B amplifier (Molecular Devices, San Jose, CA, USA), low-pass filtered at 5 kHz (Bessel, 8-pole) and digitized at 10 kHz with a National Instruments data acquisition board (BNC 2110, National Instruments, Austin, TX, USA). All data were acquired with EVAN (custom-designed LabView-based software).
Tonic current measurement. A custom written procedure (Wavemetrics, IGOR Pro 6.22A, Lake Oswego, OR, USA) was used to perform the analysis. An all-points histogram of a randomly selected recording segment of 10 s during the period of interest was plotted. A Gaussian was fitted to the part of the distribution from the minimum value at the left to the rightmost (largest) value of the histogram distribution. The mean of the fitted Gaussian was considered to be the tonic current (I_tonic). This process was repeated for all segments of interest.
Evoked current measurement. Evoked currents were extracted from continuous current recording and baseline corrected. The measurement of amplitude and decay time is described in legend of Fig. S2.

Four unidirectional piezoelectric sensors (model 208C02, PCB Piezotronics, Depew, NY) were used to measure the force produced by individual fingers. The sensors were attached with threaded rods to the slots in the top plate of the frame of the experimental device (suspension device, Figure 1A). This configuration allowed vertical adjustments in a range of 40 mm. The slots were placed 30 mm apart in the mediolateral direction and allowed adjustments in the finger longitudinal direction in a range of 150 mm. Both vertical and longitudinal adjustments could be made to accommodate individual differences in finger anatomy. A loop of aircraft cable was suspended from each sensor; the bottom end of the loop was covered in rubber to allow for comfortable finger placement. A hand fixation system was used to stabilize the palm of the hand to ensure a constant hand configuration throughout the experiment (Fig. 1B). A 20″ monitor was located 0.6 m from the subject’s head at eye level, to set tasks and provide visual feedback on their performance.
The signals from each sensor were sent through a signal conditioner (PCB, model 484B06) to a 16-bit analog-to-digital converter (BNC 2110; National Instruments). A LabVIEW-based software (National Instruments, Austin, TX) was developed to display visual feedback and record the force signals from individual fingers at 1000 Hz.