The eNTERFACE06_EMOBRAIN Database

The eNTERFACE06_EMOBRAIN database gather emotionally driven physiological signals from both the peripheral (galvanic skin response, respiration and blood volume pressure) and central nervous system (EEG and frontal fNIRS). The objective of this database is to provide a common framework for emotion assessment from multimodal physiological signals. It is a part of the more complete one acquired during the eNTERFACE'06 workshop by the "Emotion Detection in the Loop from Brain Signals and Facial Images" team [1].

CONTENTS

We recorded data from five participants all male, and right handed, with age ranging from 22 to 38. While we were recording their activity, these participants were stimulated using images from the IAPS (International Affective Picture System [2]) divided in three categories : exciting negative, neutral and exciting positive. Each person participated to three different sessions. For synchronisation between modalites a trigger, present in all the acquisition files, denotes the starting time of each stimuli or the begining of a session. In order to deal with the problem of emotion consistency across participants (ie : two subjects may experience a very different feeling during the same stimulus) we also asked them to self-assess their emotions on a simplified version of the SAM (Self-Assessment Manikin) scale. The whole protocol for data acquisition is detailed in [1].

For each participant A and session B you will find the following files :

  • PARTA_IAPS_SESB_EEG_fNIRS_DDMMAAAA.bdf : Biosemi Data Format file containing peripheral, EEG and trigger signals.
  • PARTA_IAPS_SESB_EEG_fNIRS_DDMMAAAA.bdf.mrk : list of markers (# samples) corresponding to the triggers rise for each stimulus.
  • SubjectA_SesB_EEG_fNIRS_DDMMAAAA.txt : fNIRS data in ASCII format.
  • PartASESB.log lists self-assessment of participants.
DDMMAAAA is the date of the recording.

Other data :
  • IAPS_Images_EEG_fNIRS.txt contains three columns, one per session, with the names of the IAPS pictures used in this study.
  • IAPS_Eval_Valence_EEG_fNIRS.txt and IAPS_Eval_Arousal_EEG_fNIRS.txt contains in three columns the valence or arousal value for each image.
  • IAPS_Classes_EEG_fNIRS.txt list in three columns the associated classes we considered for each block of pictures. Labels can be "Calm", "Pos" or "Neg". This can be useful if one does not want to take into account self-assessment of participants.

All these files are divided in three folders :
  • EEG folder : EEG and peripheral signals + marker files,
  • fNIRS folder : fNIRS files and the matlab code to read it,
  • Common : all other files.

TECHNICAL ASPECTS

Peripheral and EEG signals are recording using the Biosemi Active 2 device while the fNIRS concentrations are recorded using a homemade system. For EEG and peripheral activity, signals were recorded with a sampling frequency of 1024Hz wich allows to analyse frequencies up to 512Hz.
A converter from BDF to EDF (Eureupean Data Format) as well as references to the Active 2 system can be found at http://www.biosemi.com/.
Note that fNIRS files contain raw data, i.e., time-series of concentration changes for three wavelengths. A MATLAB program (loadnirs.m, avaible with the fNIRS data) is needed to convert this signal to oxygenated and deoxygenated hemoglobin values.

ERRATA

Here are some of the problems encuntered:
  • During EEG and fNIRS recordings many participants reported that they had a headache at the end of each session. This is due to the different caps that become more and more uncomfortable along time. More over, they also reported that they never felt some strong positive response while they found negative images a bit too hard. Several participants claimed that the effects of the emotional stimuli decrease after viewing many images in succession, suggesting that they became accustomed to the emotional content.
  • We could not have the chance to perform the recordings in an isolated experiment room. Thus, environmental noise definitely corrupted our recordings. However this can be handled by proper filtering.
  • During the 2nd Session of participant 1 we displayed the images of the session 1.
  • Participant 1, session 1 is recorded at a 256 Hz rate.

LICENSE

This database is available under MIT-like license conditions (the terms of this very open license are provided with the database).

DOWNLOAD

Please note that the database is very big (approx. 4 GB). Click HERE to proceed.

[1] Arman Savran, Koray Ciftci, Guillame Chanel, Javier Cruz Mota, Luong Hong Viet, Bülent Sankur, Lale Akarun, Alice Caplier and Michele Rombaut, ‘Emotion Detection in the Loop from Brain Signals and Facial Images’ , in Proc. eNTERFACE 2006, July 17th-August 11th, Dubrovnik, Croatia - available on the eNTERFACE '06 website : http://www.enterface.net/enterface06.
[2] P.J. Lang, M.M. Bradley, and B.N. Cuthbert, ‘International affective picture system (IAPS): Digitized photographs, instruction manual and affective ratings’, Technical Report A-6, University of Florida, Gainesville, FL, 2005. NIMH, Center for the study of emotion and attention.