## 2 Materials and Methods  
In this study, MER data were recorded from the electrophysiological exploration of idiopathic PD patients during DBS surgery in 'La Fe Hospital' of Valencia University, Spain. Prior to surgery, imaging techniques estimated the brain target area (STN) and optimal trajectories (bilaterally) to reach the STN. During the surgery, MER electrodes advanced in 0.2 [mm] steps, with several seconds acquisition in each step. Acquisition started 5.8 [mm] before and 0.4 [mm] after reaching the estimated STN target area. Due to surgery conditions, some were inserted in both hemispheres (bilaterally) or either right or left (see Table 1 with details for each patient). The collected data, sampled at 12 kHz, comprised a total of 830 recordings obtained from 14 patients (9 males and 5 females; age: \(65.1\pm 5.6\) years). Each MER recording corresponded to a different depth and brain lobe. For each patient, the number of steps (depths) varied (see Table 1). For each step, three acquisition channels could be used, but due to surgical practice, only one or two channels were acquired. In this work, the second channel was the only one used. Data were classified into two classes: STN-IN and STN-OUT, as in similar works [12], without considering the depth in which it was acquired. The average duration for each step in STN-IN, for the left and right lobes, was 51.0 s and 46.8 s, respectively, and the average duration for each step in STN-OUT, for the left and right lobes, was 46.3 s and 42.1 s, respectively. Each step was classified within the STN-IN or STN-OUT class by expert surgeons during the surgery process. For each acquired depth, MER data were segmented using 1 s segment duration with 50% overlapping. In total, 78,611 MER segments were obtained: 30,140 for left STN-IN, 22,725 for right STN-IN, 17,030 for left STN-OUT, and 8716 for right STN-OUT, respectively. The dataset is publicly available in ZENODO [21]. Figure 1 shows the DBS surgery process in six steps. With the patient under general anesthesia, an orifice is made in the skull, a cannula is inserted, and it is verified that the inserted position is adequate to reach the estimated position of the STN. Second, the initial target position is traced. Third, MERs are inserted and a verification that MERs are inserted is made. When MERs are inserted and the signal obtained is analyzed, the decision on the best position of the stimulation electrode is made (step 4). Finally, the stimulation electrode is inserted and the verification of stimulation is made before its final fixation (steps 5 and 6). Figure 2 shows an image of the process of CT imaging and the use of a stereotactic robot with a fiducial point to define the trajectory. \begin{table}
\begin{tabular}{l l l l l l} \hline
**Patient** & **STN-IN(L+R)** & **STN-OUT(L+R)** & **STN-IN(L+R)** & **STN-OUT(L+R)** & **Total** \\
**Number** & **\#Steps** & **\#Steps** & **Seconds** & **Seconds** & **Seconds** & **Seconds** \\ \hline
1 & 20+NA & 4+NA & 959+NA & 134+NA & 1093 \\
2 & 18+31 & 14+3 & 1354+1855 & 591+199 & 3999 \\
3 & 13+27 & 27+12 & 626+993 & 923+434 & 2976 \\
4 & 21+21 & 11+9 & 946+1114 & 629+421 & 3110 \\
5 & 26+NA & 15+NA & 1200+NA & 497+NA & 1697 \\
6 & 15+NA & 25+NA & 941+NA & 1528+NA & 2469 \\
7 & 23+NA & 7+NA & 1632+NA & 731+NA & 2363 \\
8 & 22+17 & 11+26 & 1229+1041 & 454+1141 & 3865 \\
9 & 30+37 & 8+4 & 1248+1322 & 285+114 & 2969 \\
10 & 32+32 & 15+13 & 1147+1852 & 921+557 & 4477 \\
11 & 18+NA & 19+NA & 1024+NA & 939+NA & 1963 \\
12 & 30+30 & 11+12 & 1415+995 & 380+416 & 3206 \\
13 & 29+25 & 18+14 & 1429+1119 & 548+640 & 3736 \\
14 & NA+24 & NA+11 & NA+1129 & NA+461 & 1590 \\ \hline TOTAL & 297+244 & 185+104 & 15,150+11,420 & 8560+4383 & 39,513 \\ \hline \end{tabular}
\end{table} 
Table 1: Microelectrode (MER) data recordings. Fourteen patients in total, acquired in one or both brain lobes, at a different number of depths (steps). For each patient, the number of steps and total seconds acquired are shown.