PsPM-PubFe pre-processed data
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Repository Version: 2021.11.06

This file refers to the data stored in data_pp.zip and should be read in conjunction with the main README.txt, which comments on how the data were generated.

The preprocessed dataset data_pp.zip builds on the main data set contained in data.zip and includes raw and preprocessed pupil size response (PSR), skin conductance response (SCR), electrocardiogram (ECG), and respiration measurements. Time indices of this data set correspond to the main data set. Preprocessing steps are listed below.
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General
Preprocessing was done with Matlab R2019a and PsPM version 5.1.1 as well as custom-written code. To read pupil files, a PsPM version higher than 5.5.1 is required.
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Eyetracker data 
Gaze coordinates were linearly interpolated and converted into millimetres (using pspm_convert_pixel2unit). If both eyes were recorded, the gaze data from both eyes were averaged, and then converted to scan path speed (degree/sec) without applying any filtering (using pspm_convert_gaze_distance). Pupil data were preprocessed and, if two eyes were recorded, combined (using standard settings in pspm_pupil_pp). Pupil size data for which combined gaze direction was outside ± 5° visual angle around the fixation points were discarded as missing data points (using find_valid_fixations) and were excluded for analysis.  
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SCR
SCR artefacts were detected via an initial automatic quality assessment (using standard settings in pspm_scr_pp). Data were then visually examined to detect additional artefacts. Artefact epochs are stored in separate files, as described below.
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ECG
QRS complexes were detected from ECG data using a modified Pan & Tompkins algorithm to create heartbeat time stamps (using pspm_ecg2hb). Heartbeat was then transformed into an interpolated heart rate signal (using a heart period limit of 0.4-1.2 s in pspm_hb2hp) at 100 Hz sampling rate. 
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RAR 
Raw respiratory traces were converted to interpolated respiration amplitude time series with a respiratory cycle detection algorithm (using standard settings in pspm_resp_pp) at 10 Hz sampling rate.


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This repository is curated by the PsPM team, bachlab.org/pspm
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The preprocessed dataset is described and used in following references:
N/A
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File Structure:
-README_pp.txt               		// This document
-+Data_pp                    		// Folder Containing all data files
 |-PubFe_pupil_XX_snY_pp.mat  		// 44 files holding pupil measurements
 |-PubFe_wdq_XX_snY_pp.mat    		// 44 files holding measurements for SCR, ECG, EMG and respiration
 |-missing_epochs_PubFe_wdq_XX_snY      // 44 files holding detected SCR artefact epochs
 |-...

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Data Files:
- Files holding pupil traces and time markers, recorded with Eyelink software.
   - Event markers used for synchronization with Cogent files, marker are set at CS presentation onset (channel 1)
   - Pupil size for left pupil (channel 2)
   - Gaze coordinate x for left pupil (channel 3)
   - Gaze coordinate y for left pupil (channel 4)
   - Pupil size for right pupil (channel 5)
   - Gaze coordinate x for right pupil (channel 6)
   - Gaze coordinate y for right pupil (channel 7)
   - Gaze coordinate x for left pupil in mm (channel 8)
   - Gaze coordinate y for left pupil in mm (channel 9)
   - Gaze coordinate x for right pupil in mm (channel 10)
   - Gaze coordinate y for right pupil in mm (channel 11)
   - Preprocessed pupil size combined for both eyes (channel 12)
   - Scanpath speed (channel 13)
- Files holding SCR, ECG, respiration traces and time markers, recorded with WDQ software.
   - Skin conductance (channel 1)
   - Electrocardiogram (channel 2)
   - Respiration (channel 3)
   - Event markers used for synchronization with Cogent files, markers are set at CS presentation onset (channel 4)
   - Heart beat time stamps (channel 5)
   - Interpolated heart period (channel 6)
   - Interpolated respiration amplitude (channel 7)
- Files holding SCR artefact epochs, created with pspm_data_editor

The data file name is composed of:
 - missing_epochs_	for missing epochs files 
 - PubFe        	The dataset name
 - pupil/wdq    	The type of data recorded (see above)
 - XX           	The subject number
 - Y           	The block number (1 or 2)

Data are stored as .mat files for use with MATLAB (The MathWorks Inc., Natick, USA) in a format readable by the PsPM toolbox (bachlab.org/pspm). All Matlab files are saved in MATLAB 9.6 (R2019a) format.