With the aim of developing a brain-computer interface for the communication of basic mental states, a classical conditioning paradigm with affective stimuli was used, assessing the possibility to discriminate between affirmative and negative thinking in an fMRI-BCI setting. 6 Alzheimer patients and 7 healthy control subjects participated to the study. Congruent and incongruent word-pairs were respectively associated to pleasant (baby laughter) and unpleasant (scream) affective stimuli. A Support Vector Machine classifier focusing on insula, amygdala and anterior cingulate cortex was used to discriminate between the activations relative to congruent and incongruent word-pairs (eliciting respectively affirmative and negative thinking), following the conditioning process. Classification accuracy was on average 71% for Alzheimer patients, reaching 85%, and on average 69% for control subjects, reaching 83%. This study shows that it is possible to extract information on individuals' mental states by exploiting affective responses, overcoming the typical obstacles of traditional BCIs, which generally require time-consuming trainings and intact cognition.
Liberati, G., Dalboni da Rocha, J., Veit, R., Kim, S., Birbaumer, N., Von Arnim, C., Jenner, A., Lulé, D., Ludolph, A., Raffone, A., Olivetti Belardinelli, M., Sitaram, R., & et al. (2013). Development of a Binary fMRI-BCI for Alzheimer Patients: A semantic conditioning paradigm using affective unconditioned stimuli. IEEE Transactions on Affective Computing, 1, 838-842. https://doi.org/10.1109/ACII.2013.157 (Original work published 2012)