Data for Handwriting Imagery(LTVA&HTVA)

Description

This dataset includes offline data from handwriting imagination brain computer interfaces, fNIRS data, scale data, and BCI online testing data under two paradigms, namely Low Temporary Variation Abundance (LTVA) and High Temporary Variation Abundance (HTVA); The former includes EEG under 8 directions of straight line handwriting imagination task, while the latter includes EEG under 8 curved letter handwriting imagination task; The fNIRS data represents the changes in parietal blood oxygen during LTVA and HTVA, and the scale measures cognitive load before and after the experiment. Finally, EEG data from multiple subjects undergoing BCI online testing and HWI were included.

Steps to reproduce

In this study, HWI straight lines and hyphenated characters were internal psychological activities that required subjects to imagine the process of holding a pen with their right hand on a piece of paper and writing straight or hyphenated characters from a first-person perspective. The timing of a single experiment based on EEG with 0-10 seconds after the start of the experiment as the experimental guidance language. Subjects should pay attention to the guidance language; During the period of 10-13 seconds, the subjects were animated to indicate one of the eight straight lines or one of the eight hyphenated characters in the HWI; During the period of 13-16 seconds, subjects performed HWI prompts; During the period of 16-19 seconds, the subjects remained awake and relaxed. The timing of a single trial based on fNIRS with a baseline of 0-30 seconds after the start of the trial, and subjects remaining awake and relaxed; During the period of 30-33 seconds, the subjects were animated to indicate one of the eight straight lines or one of the eight hyphenated characters in the HWI; 33-45 seconds for subjects to perform HWI prompts; During the 45-57 second period, the subjects remained awake and relaxed. The entire experiment divided 16 types of HWI with 8 straight lines and 8 hyphenated characters with 8 directions into 4 groups, each consisting of 2 straight lines and 2 hyphenated characters in 2 directions. There were 4 types of HWI, and each type of HWI included 20 trials. Before each group of experiments, subjects filled out the "Self State Assessment Scale" to exclude data from subjects with poorer states in the future. The subjects sat in comfortable chairs with their hands on the table. Before the formal experiment, they were trained to concentrate by using a 5*5 Schultz grid. During the formal trial, the subjects performed HWI according to the sequence. After the completion of each group of trials, the subjects filled in the NASA-Tlx cognitive load scale , and arranged a 5~10 minutes rest between the trials of each group.EEG collection using EEG device for 16 leads with sampling frequency of 1000Hz, and 24-bits A/D converter, and no power frequency notch; The EEG signals of F3, Fz, F4, C3, C4, Cz, P3, Pz, and P4 electrodes were recorded using a 16 leads electrode cap customized for the 10-20 system. The reference electrode Ref was between Cz and Pz, and the ground electrode GND was located on the centerline of Fp1 and Fp2, in front of Fz, as shown in Figure 3 (a). The device of fNIRS acquisition is a portable 16 channel (China Danyang Huichuang Nir Smart) with a sampling frequency of 20Hz and a 24-bits A/D converter, and a communication interface of WIFI. placed in the top and left and right sides, corresponding to the 1-7 zones of the Broadman area [26]. The S1-D1 channel corresponds to the Cz position, the S2-D2, S3-D2, S2-D3, S2-D4, and S3-D4 channels cover C4, and the S4-D5, S5-D5, S4-D7, S4-D8, and S5-D8 channels cover C3.

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