Sunjung Kim

Real-time functional MRI neurofeedback: a tool for psychiatry.

Purpose of review The aim of this review is to provide a critical overview of recent research in the field of neuroscientific and clinical application of real-time functional MRI neurofeedback (rtfMRI-nf). Recent findings RtfMRI-nf allows self-regulating activity in circumscribed brain areas and brain systems. Furthermore, the learned regulation of brain activity has an influence on specific behaviors organized by the regulated brain regions. Patients with mental disorders show abnormal activity in certain regions, and simultaneous control of these regions using rtfMRI-nf may affect the symptoms of related behavioral disorders. Summary The promising results in clinical application indicate that rtfMRI-nf and other metabolic neurofeedback, such as near-infrared spectroscopy, might become a potential therapeutic tool. Further research is still required to examine whether rtfMRI-nf is a useful tool for psychiatry because there is still lack of knowledge about the neural function of certain brain systems and about neuronal markers for specific mental illnesses.

Insula and inferior frontal triangularis activations distinguish between conditioned brain responses using emotional sounds for basic BCI communication

In order to enable communication through a brain-computer interface (BCI), it is necessary to discriminate between distinct brain responses. As a first step, we probed the possibility to discriminate between affirmative (“yes”) and negative (“no”) responses using a semantic classical conditioning paradigm, within an fMRI setting. Subjects were presented with congruent and incongruent word-pairs as conditioned stimuli (CS), respectively eliciting affirmative and negative responses. Incongruent word-pairs were associated to an unpleasant unconditioned stimulus (scream, US1) and congruent word-pairs were associated to a pleasant unconditioned stimulus (baby-laughter, US2), in order to elicit emotional conditioned responses (CR). The aim was to discriminate between affirmative and negative responses, enabled by their association with the positive and negative affective stimuli. In the late acquisition phase, when the US were not present anymore, there was a strong significant differential activation for incongruent and congruent word-pairs in a cluster comprising the left insula and the inferior frontal triangularis. This association was not found in the habituation phase. These results suggest that the difference in affirmative and negative brain responses was established as an effect of conditioning, allowing to further investigate the possibility of using this paradigm for a binary choice BCI.

fNIRS as a Method to Capture the Emotional User Experience: A Feasibility Study

User experience (UX) has become a key factor in interface design. Still, so far, no satisfying solution exists for measuring the emotional user experience (UX) during human-technology interaction (HTI) and linking them to design elements of the interface. Non-invasive brain imaging techniques are promising tools to assess the underlying causes and generation of emotional experiences in the brain. Against this background, especially functional near-infrared spectroscopy (fNIRS), a rather new and portable method, appears to have strong potential for measuring UX in real-world HTI settings. However, so far fNIRS has scarcely been used in emotion research. The present research evaluates the feasibility of using fNIRS to detect emotional user responses during HTI by comparing it to the well-established method of fMRI which, due to its set-up, is difficult to use in HTI context. Our feasibility study shows that fNIRS can detect brain activity patterns which are similar to those obtained using fMRI and can be used to distinguished positive and negative emotional reaction in an HTI context and displays brain activities which cannot be examined when fMRI is used. Future research should investigate whether similar results can be found when fNIRS is used in less controlled and more realistic HTI scenarios.

Classical conditioning of the BOLD signal as a paradigm for basic BCI communication in Alzheimer patients

Background Alzheimer patients express their need of social interaction even when their communication abilities are highly impaired. (Mayhew et al., 2001). Brain-computer interfaces (BCI), already used with severely paralyzed patients, may be adapted for communicating with Alzheimer patients by shifting the paradigm from instrumental-operant learning to classical conditioning (Birbaumer, 2006), e.g. by associating “yes” thinking to a positive emotion and “no” thinking to a negative emotion. We designed an fMRI-based BCI setting aimed at conditioning subjects to associate positive and negative emotional stimuli with respectively congruent and incongruent word pairs, in view of a BCI application for basic yes/no communication. Methods fMRI was performed on 6 healthy subjects during a classical conditioning session, comprising the phases of habituation, acquisition and extinction. The unconditioned stimuli consisted of a positive (baby laughter) and negative (scream) emotional sound. The conditioned stimuli, presented aurally, were congruent (e.g. “animal-elephant”) and incongruent (e.g. “animal-Germany”) word pairs. During the conditioning acquisition phase, congruent word pairs were associated to the baby laughter and incongruent word pairs were associated to the scream. A linear Support Vector Machine was implemented to classify the BOLD signal corresponding to congruent and incongruent word pairs. To investigate the relative importance of distinct brain areas in decoding different brain states, feature vectors from the frontal cortex were also used as input to build a separate classifier. Results Participants rated in the Self Assessment Manikin (SAM) the scream and the laughter as having, respectively, negative and positive valence. Moreover, the scream was associated to higher arousal compared to the baby laughter. Classification of the BOLD signal as a response to the congruent and incongruent word pairs immediately followed by the emotional unconditioned stimuli showed above chance level performance (57-64%) in one subject, while the performance was chance level on the remaining subjects (44-56%). Conclusions We presented a possible paradigm for basic yes/no communication, based on the conditioning of BOLD signal by the repeated association of emotional and semantic stimuli. The performance of the classifier by feature selection needs to be improved before being tested with Alzheimer patients. Future developments also comprise an online implementation of the system.