Digital headstage processor

Stereotrodes were lowered 60 µm interval each day before recording. During sessions, neural activity and signals before, during, and after, pinprick stimulations were recorded at a sample rate of 40 kHz using acquisition equipment (OmniPlex D with Digital Headstage Processor, Plexon). Raw data of LFPs was digitally filtered with a bandpass filter between 0.3 and 300 Hz and then down-sampled to 1 kHz.

In this study, we recorded the kinematics and EEG data of rats. The kinematics data were recorded by four cameras (80 Hz) using the Plexon CinePlex system (Plexon Inc., Dallas, TX, USA). The motion of each rat was recorded and saved synchronously with EEG data for behavioral analysis and gait event extraction. The EEG data were collected by the home-designed 32-channel electrode array (Figure 1A). The EEG electrodes array was fabricated on a flexible polyimide substrate using photolithography, metal deposition, and etching techniques. The array was comprised of 34 microelectrodes, each with a diameter of 500 µm, which include 32 working electrodes, one reference electrode (REF), and one ground electrode (GND). The GND and the REF were both on the same side and were not symmetrical (Figure 1B). It is worth noting that the signals from the GND and the REF were excluded, and only the signals from the 32 working electrodes were retained for analysis. The interface of the electrode array was connected to the Digital Headstage processor (Plexon Inc.) through a cable. The EEG data were sampled at 2000 Hz and a notch filter was used to reduce line noise (50 Hz). The EEG data were transmitted to the OmniPlex neural data acquisition system (Plexon Inc.) for storage.

Stereotrodes were lowered in steps of 60 µm before each day of recording. The neuronal activity and the onset of pin prick stimulation were simultaneously recorded with acquisition equipment (OmniPlex D with Digital Headstage Processor, Plexon). Signals were monitored and recorded at a sample rate of 40 kHz. To get spike activity, the raw data were band pass filtered from 300 Hz to 7.5 kHz with subsequent offline sorting, using commercial software (Offline Sorter, Plexon). Trials were aligned to the initiation of the peripheral stimulus to compute the peri-stimulus time histograms (PSTHs) for each single unit using MATLAB (Mathworks).