Passive Viewing of Emotion-Evoking Images Using EEG and fNIRS
Emotions play an important role in daily life, therefore understanding the underlying neural mechanisms of emotional processing is important both in a clinical and everyday setting. The basic emotion model assumes that each emotion has its own patterns of brain activity . Consequently, the number of debates in affective neuroscience on how emotions are organized in the brain is on the rise, together with neuroimaging studies of emotional processing.
Up to recently most research studies focused on describing the valence of stimuli response without regard to how that measure corresponds to basic emotions like fear, anger, and disgust. Thus, no study researching the patterns of brain activity during the discrete states of basic emotions has been done .
We will examine the brain's response to viewing pictures that evoke the emotions of disgust, joy, and sadness, which have been selected based on efficiency of measuring the response while viewing the images. We will simultaneously use electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Previous research using this combination showed activity of prefrontal cortex, the part of the brain we will examine. Our main hypothesis is that we will observe a statistically significant difference in the brain activity between the aforementioned emotions.
In our measurements, we will use a combination of EEG and fNIRS. With EEG-fNIRS hybrid measurements, we will detect the electrical activity in the brain (EEG) concurrently with hemodynamic responses (fNIRS), which will provide us with more comprehensive data on the brain activity. For emotion elicitation/evocation, we will use 400 stimuli containing images from multiple image databases. The stimuli will be divided into 4 categories of basic emotions: disgust, fear, joy, and neutral state. After the viewing we will use a questionnaire to attribute participants’ evoked emotions to the image. The study will include 40 healthy, right-handed participants aged between 18 and 60 years.
We expect to obtain results that will reflect statistically significant differences in brain activity among selected categories of basic emotions. With that we expect a correlation between areas with higher/lower levels of oxygenated hemoglobin and statistically significant ERPs. Since the expected differences in brain responses across emotional categories will not be attributed to differences in arousal or valence of stimuli, the obtained results will elucidate patterns of brain activity underlying basic emotions.
 R. Adolphs, "How should neuroscience study emotions? by distinguishing emotion states, concepts, and experiences", Social Cognitive And Affective Neuroscience, vol. 12, no. 1, pp. 24-31, 2016.
 M. Balconi, E. Grippa and M. E. Vanutelli, "What hemodynamic (fNIRS), electrophysiological (EEG) and autonomic integrated measures can tell us about emotional processing", Brain and cognition, vol. 95, pp. 67-76, 2015.