Time-Varying Spectral Analysis of a Single EEG Channel: Application in an Affective Protocol

Neural correlates of emotions have been widely investigated using noninvasive sensor modalities. These approaches are often characterized by a low level of usability and are not practical for real-life situations. The aim of this study is to show that a single EEG electrode placed in the central region of the scalp is able to discriminate emotional characterized events with respect to a baseline period. Emotional changes were induced using an imagery approach based on the recall of autobiographical events characterized by four basic emotions: "Happiness", "Fear", "Anger" and "Sadness". Data from 17 normal subjects were recorded on Cz position according to the International 10-20 System. After preprocessing and artifact detection phases, raw signals were analyzed through a time-variant adaptive autoregressive model to extract EEG characteristic spectral components. We considered 5 frequency bands, i.e. the classical EEG rhythms, namely the delta band (δ), [1-4] Hz, the theta band (θ), [4-6] Hz, the alpha band (α), [6-12] Hz, the beta band (β), [12-30] Hz, and the gamma band (γ), [30-50] Hz. The relative powers of the EEG rhythms were used as features to compare the experimental conditions. Our results show statistically significant differences when comparing the power content in the gamma band of baseline events versus emotionally characterized events. Particularly, we found a significant increase in gamma band relative power in 3 out of 4 emotionally characterized events, i.e. “Happiness” “Sadness” and “Anger". In agreement with previous studies, our findings confirm the presence of a possible correlation between broader high frequency cortical activation and affective processing of the brain. The present study shows that the use of a single EEG electrode represents a possible advantageous premise for the assessment of the emotional state with a minimally invasive set-up

Influence of different drying parameters on the composition of volatile compounds of thyme and rosemary cultivated in Sardinia

The shelf life of spices is traditionally extended by drying. Fresh herbs, due to their high water content, undergo microorganism growth and adverse biochemical reactions. On the other hand drying may result in a lot of physical and chemical alterations. Air and oven-dehydration are the main methods used to stabilize spices. During oven drying, in general, losses of volatile compounds are directly dependent on the temperature and time used. This paper deals with the effect of different drying temperatures and air fluxes on the volatiles in rosemary (Rosmarinus officinalis L.) and thyme (Thymus officinalis L.) cultivated in Sardinia. Fresh leaves were collected and soon divided in two batches, which were subjected to hydro distillation and GC-MS analysis, the first batch as fresh, the second one after drying in a laboratory pilot dryer. Three drying temperatures were used, 30, 38 and 45°C, and for each one two airflow rates were set. The fresh and dried plant material were hydro distilled for 4 hours using a Clevenger-type apparatus (Italian Official Pharmacopeias X). The oils (liquid and light yellow) were recovered directly from above the distillate without adding any solvent and stored at –20°C before analyses, which were carried out on two replicates of each sample by gas chromatography, using a flame ionization detector. The diluted samples were injected using a split/splitless automatic injector (using 2,6-dimethylphenol as internal standard). Qualitative analysis was done by GC/Mass and mass units were monitored from 10 to 450 at 70 eV. Results of the influence of the different drying conditions on volatile compounds of the two herbs will be reported

Heavy Metals Size Distribution in PM10 and Environmental-Sanitary Risk Analysis in Acerra (Italy)

The present research has been focused on the evaluation of seasonal changes in mass concentrations and compositions of heavy metals in Particular Matters (PM)10 collected from a typical urban-industrial site in Acerra, a city located in an area called "triangle of death". No significant (p < 0.05) seasonal variation was evidenced for the PM10 concentration, but in all the seasons (except for autumn) exceedances of daily concentrations (50 μg m−3) were observed. Airborne PM was analyzed for these heavy metals: Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn, which represented about 8% of the PM10 concentrations. None of the metals classified by IARC as carcinogenic in humans (group 1) exceeded on average the annual EU's and Italy's limit. For the mentioned heavy metals the enrichment factors (EnFs) were analyzed and highlighted high enrichment for Cd, Sb, Pb, As, Cu and Zn. Principal component analysis (PCA) for the heavy metals in PM10 identified oil combustion, vehicle and industrial emissions as major sources. To assess the health risk related to the inhalation to airborne PM10 metals, we applied the Cancer Risk (CR) and Target Hazard Quotient (THQ). The results showed that the CR was similar for a child and an adult, while the THQ proved to be higher for a child than for an adult. The low PM metals risk in the urban industrial site was in agreement with the ongoing lowering trend of metals in Italy and Europe

Parietal resting-state EEG alpha source connectivity is associated with subcortical white matter lesions in HIV-positive people

Objective Parietal resting-state electroencephalographic (rsEEG) alpha (8–10 Hz) source connectivity is abnormal in HIV-positive persons. Here we tested whether this abnormality may be associated with subcortical white matter vascular lesions in the cerebral hemispheres. Methods Clinical, rsEEG, and magnetic resonance imaging (MRI) datasets in 38 HIV-positive persons and clinical and rsEEG datasets in 13 healthy controls were analyzed. Radiologists visually evaluated the subcortical white matter hyperintensities from T2-weighted FLAIR MRIs (i.e., Fazekas scale). In parallel, neurophysiologists estimated the eLORETA rsEEG source lagged linear connectivity from parietal cortical regions of interest. Results Compared to the HIV participants with no/negligible subcortical white matter hyperintensities, the HIV participants with mild/moderate subcortical white matter hyperintensities showed lower parietal interhemispheric rsEEG alpha lagged linear connectivity. This effect was also observed in HIV-positive persons with unimpaired cognition. This rsEEG marker allowed good discrimination (area under the receiver operating characteristic curve &gt; 0.80) between the HIV-positive individuals with different amounts of subcortical white matter hyperintensities. Conclusions The parietal rsEEG alpha source connectivity is associated with subcortical white matter vascular lesions in HIV-positive persons, even without neurocognitive disorders. Significance Those MRI-rsEEG markers may be used to screen HIV-positive persons at risk of neurocognitive disorders

Eye-tracking recordings and psychophysiological reactions

Nowadays the techniques that study consumers’ behaviour can take advantage of neuroscientific findings. That is why researchers have initiated discussions on a new research field, Neuromarketing. Although this is a promising field, many issues about the use and application of neuroscientific tools, methods and technologies are still being debated in the scientific community. It is not evident yet how to apply the results and methods provided by neuroscience and psychophysiological research into the practice of marketers, even though other social sciences, such as economics, have already integrated neuroscience into a new research field called neuroeconomics. To add empirical data to these topics, we showed 30 IULM students 20 advertising flyers. They were asked to come to the Brain and Behavior Lab on IULM University campus and sit in front of a computer while their neuro and psychophysiological reactions were recorded with non-invasive sensors: namely, EEG, EMG, Galvanic Skin Response, Heart Rate and Respiration. The recording device was synchronized with an eye-tracker system, in order to measure the pupil dilation, as an additional contactless indicator of emotional reactions, and the tracking of subjects’ gaze pointing to the PC screen. Firstly, the data analysis revealed that the most successful flyer, according to the expressed opinions of the students, is characterized by a specific pattern of neuro and psychophysiological signals. In contrast, the least successful flyer was associated with another specific pattern. These data results might help in designing a procedure to test advertising flyers based on neuro and psychophysiological reactions

Eye-tracking recordings and psychophysiological reactions

In the last years neuroscience has brought up many discoveries about the brain to an unprecedented level. Nowadays the tools that can study consumers’ behaviour might take advantage of neuroscientific techniques (Knutson et al., 2005 and 2007). Nevertheless, the possibility to take advantage of some neuroscientific approaches in social sciences like marketing is not evident yet. In psychology and physiology researchers are rapidly applying neuroscientific techniques in order to carry on their researches and to improve their understanding of human cognition. In sociology, some researchers that explored how culture might affect the perception and interpretation of affective stimuli already showed very interesting results by mean of biological evidences (Scherer et al., 2009; Scherer 1997). However, social sciences like marketing did not integrated neuroimaging as a new tool or method to make more comprehensive its studies. On one side, economics has started to introduce neuroimaging in its researches, leading to the creation of a new scientific discipline called “neuroeconomics” (e.g. Braeutigam, 2005; Kenning and Plassmann, 2005; Rustichini, 2005). On the other side, in the marketing field the possibility to take advantage of neuroscientific approach and biological evidences is still far away to be accomplished, despite both fields of research share many common interests about communication, decision making,human behaviour, personality and cultural issues. Some difficulties in applying neuroscientific approaches to marketing might rely on ethical issues, since studying human behaviour by means of neuroimaging might lead to the risk of manipulation. However, despite the common belief on the evil nature of marketing, its chief goal is to help match products with people (Ariely, 2010). On one side marketing guides the design of presentation of products in such a way that they might become more compatible with consumers preferences. On the other side, marketing should facilitate the choice process of consumers, according to their personality and cultural profiles. For both issues, communication strategies and advertising have an important role. However, aside the traditional techniques like focus groups and surveys, aimed to increase the probability of success about the presentation of new products, nowadays it does not exist a shared procedure or technique to objectively and quantitatively evaluate the impact of communication and advertising, to assess whether they are engaging or not or in what extent they elicit a level of engagement in terms of biological patterns reflecting a specific experience marked by attention and emotions. The final goal of this research branch is to study the communication efficacy applying evidence-based techniques. In order to fill this lack of integrations between marketing and neuroscience and to add empirical data in this field, we carried on an exploratory study where we exposed a group of students to two advertising spots while their psychophysiological and eye-tracking measures were monitored. In this paper we present some preliminary univariate analyses reported in the results section, and we will refer to the scientific framework of the Theory of Flow and to the Valence-Arousal Model of affective states in order to discuss and interpret the results. We will try to answer to the following first Research Questions: 1) is the experience of watching a spot associated with a specific psychophysiological state? The aim is to explore the possibility to use psychophysiological measures that identify the specific pattern of users’ affective state while experiencing the vision of advertising spots. In particular, we aim to explore the following second Research Question: 2) is the psychophysiological state of people watching the preferred spots (amongst two) characterized by a specific pattern

Eye-tracking e reazioni psicofisiologiche combinate con opinioni espresse in merito a spot pubblicitari

Oggi le tecniche che studiano il comportamento dei consumatori possono avvantaggiarsi di tecniche neuroscientifiche (Knutson et al., 2005). Per questa ragione alcuni ricercatori hanno iniziato a parlare di un nuovo campo di studi definito come “Neuromarketing” (Lee et al., 2007). Sebbene questo sia un campo promettente, ci sono ancora molti fattori da definire riguardo la possibilità di applicare tecniche di immagine usate nel campo delle neuroscienze, fattori che hanno già avviato un dibattito all’interno della comunità scientifica (Ariely et al., 2010). Per esempio, la definizione dei pattern psico-fisiologici che correlano con le emozioni (Rainville et al., 2006), poiché le emozioni hanno un ruolo rilevante nelle scelte di acquisto (Mano, 1999). Un altro punto da definire riguarda anche i pattern psicofisiologici legati al decision making, altro campo di studi in espansione (Knutson et al., 2007). Altri fattori che richiedono ulteriori definizioni metodologiche riguardano la capacità statistica e bio-ingegneristica di inferire informazioni, a partire da dati psicofisiologici (Picard, 1997), in grado di indicare il livello di piacevolezza e di gradimento di uno stimolo o di una certa esperienza senza obbligare il soggetto a rispondere a delle domande in merito; in altre parole, una “opinione psicofisiologica” dello stimolo o dell’esperienza percepita. Ricerche precedenti di questo tipo hanno studiato le emozioni grazie alla combinazione di categorie definite “Attivazione” (Arousal) e Valenza (Valence) (Lang, 1995).) e attraverso studi sul coinvolgimento o “Flow”, frutto dell’interazione di processi emotivi, attentivi e mnestici (Csikszentmihalyi, 1990; De Manzano et al., 2000; Mauri et al., 2010). Al fine di aggiungere dati sperimentali riguardo questi temi, in questo studio abbiamo esposto 30 studenti IULM ad un paio di spot pubblicitari sulla stessa tipologia di prodotto dopo averli invitati a presentarsi presso i laboratori sperimentali dell’Università IULM di Milano. Durante l’esposizione i seguenti indici psico-fisiologici sono stati monitorati: Elettroencefalografia dei lobi frontali, Elettromiografia dei muscoli facciali “Corrugator Supercilii”, la sudorazione dei palmi delle mani, la variabilità cardiaca attraverso un sensore fotopletismografico sulla punta di un dito della mano non dominante, e il ritmo respiratorio attraverso un sensore collocato sul petto. L’acquisizione di tutti gli indici è stata sincronizzata attraverso un opportuno protocollo (Cipresso et al., 2010) con una apparecchiatura Eye-tracking per tracciare il movimento dello sguardo sullo schermo del pc e per monitorare la dilatazione della pupilla, ulteriore indicatore psico-fisiologico dello stato emotivo dei soggetti. I due spot pubblicitari sono stati presentati a random per 30 secondi sullo schermo di un computer. Dopo ciascuno spot, ai soggetti è stato chiesto di esprimere il proprio giudizio di gradimento dello spot stesso su una scala compresa tra 0 (non mi è piaciuto per niente) e 100 (mi è piaciuto tantissimo). Nelle nostre analisi preliminari si cerca di combinare i risultati emersi dai giudizi con le reazioni psico-fisiologiche e con i tracciamento dello sguardo al fine di valutare l’impatto sortito dai due spot pubblicitari. I primi risultati emersi dalle registrazioni psicofisiologiche e eye-tracking possono fornire informazioni utili riguardo il livello di gradimento e le intenzioni di acquisto da una parte e il livello di coinvolgimento o “Flow” durante l’esposizione ai due spot pubblicitari dall’altr

Eye-tracking recordings and psychophysiological reactions

In the last years neuroscience has brought up many discoveries about the brain to an unprecedented level. Nowadays the tools that can study consumers’ behaviour might take advantage of neuroscientific techniques (Knutson et al., 2005 and 2007). Nevertheless, the possibility to take advantage of some neuroscientific approaches in social sciences like marketing is not evident yet. In psychology and physiology researchers are rapidly applying neuroscientific techniques in order to carry on their researches and to improve their understanding of human cognition. In sociology, some researchers that explored how culture might affect the perception and interpretation of affective stimuli already showed very interesting results by mean of biological evidences (Scherer et al., 2009; Scherer 1997). However, social sciences like marketing did not integrated neuroimaging as a new tool or method to make more comprehensive its studies. On one side, economics has started to introduce neuroimaging in its researches, leading to the creation of a new scientific discipline called “neuroeconomics” (e.g. Braeutigam, 2005; Kenning and Plassmann, 2005; Rustichini, 2005). On the other side, in the marketing field the possibility to take advantage of neuroscientific approach and biological evidences is still far away to be accomplished, despite both fields of research share many common interests about communication, decision making,human behaviour, personality and cultural issues. Some difficulties in applying neuroscientific approaches to marketing might rely on ethical issues, since studying human behaviour by means of neuroimaging might lead to the risk of manipulation. However, despite the common belief on the evil nature of marketing, its chief goal is to help match products with people (Ariely, 2010). On one side marketing guides the design of presentation of products in such a way that they might become more compatible with consumers preferences. On the other side, marketing should facilitate the choice process of consumers, according to their personality and cultural profiles. For both issues, communication strategies and advertising have an important role. However, aside the traditional techniques like focus groups and surveys, aimed to increase the probability of success about the presentation of new products, nowadays it does not exist a shared procedure or technique to objectively and quantitatively evaluate the impact of communication and advertising, to assess whether they are engaging or not or in what extent they elicit a level of engagement in terms of biological patterns reflecting a specific experience marked by attention and emotions. The final goal of this research branch is to study the communication efficacy applying evidence-based techniques. In order to fill this lack of integrations between marketing and neuroscience and to add empirical data in this field, we carried on an exploratory study where we exposed a group of students to two advertising spots while their psychophysiological and eye-tracking measures were monitored. In this paper we present some preliminary univariate analyses reported in the results section, and we will refer to the scientific framework of the Theory of Flow and to the Valence-Arousal Model of affective states in order to discuss and interpret the results. We will try to answer to the following first Research Questions: 1) is the experience of watching a spot associated with a specific psychophysiological state? The aim is to explore the possibility to use psychophysiological measures that identify the specific pattern of users’ affective state while experiencing the vision of advertising spots. In particular, we aim to explore the following second Research Question: 2) is the psychophysiological state of people watching the preferred spots (amongst two) characterized by a specific pattern

Eye-tracking recordings and psychophysiological reactions versus expressed opinions about advertising spots

Nowadays the tools that can study consumers’ behaviour might take advantage of neuroscientific techniques (Knutson et al., 2005). This is the reason why some researchers started to propose a new field, Neuromarketing. Although this is a promising field, there are still many issues about the use and the application of neuroscientific findings, methods and technologies that are still debated in the scientific community (Ariely et al., 2010). For instance, the uncovering of the links between affective states and biological correlates (Rainville et al., 2006), since emotions are significant in purchase intentions (Mano, 1999). Another issue is the uncovering of the links between decision making and biological predictors (Knutson et al., 2007). Another hot topic is also related to the ability to extract information from biological data aimed to indicate the amount of pleasantness of the stimulus without asking subjects to answer some questions about it; in a few words, a “psychophysiological opinion” of perceived stimulus or experience, that in the field of psychophysiology has been named Valence (Lang, 1995). Although about these issues there are many new research groups, for instance the Affective Computing Group (Picard, 1997), it is not clear yet how to apply these research findings and methods in practice. Last but not least, the implementation of non-invasive, wearable and wireless sensors might allow in future the possibility to infer from biological and psychophysiological data the level of engagement or Flow (Csikszentmihalyi, 1990; De Manzano et al., 2000; Mauri et al., 2010), a potential measure of the level of consumers’ attention dedicated to products or services, not only in experimental environment within labs or in front of a computer, but also in real world situations. This possibility might represent an interesting and innovative area in consumer researches aside traditional ones. In order to add empirical data about these topics, in this study we showed 30 IULM students a couple of advertising spots. They were asked to come at our Lab and sit in front of a computer while their psychophysiological reactions were recorded with non-invasive sensors: namely, EEG of the frontal lobes, EMG of Corrugator Supercilii muscle, Galvanic Skin Response from the palms, Heart Rate Variability from a Photoplethysmograph on a finger and Respiration from a chest belt. The recording device was synchronized with an eye-tracker system, in order to get pupil dilation, as an additional contactless indicator of emotional reactions, and the tracking of subjects’ gaze pointing on the PC screen. The 2 advertising spots were randomly presented for 30 seconds on a PC screen. After each spot, subjects were asked to express their level of liking of the adv spot on a scale between 0 (I don’t like it at all) and 10 (I like it very much). Since we were recording EEG and EMG signals from the frontal lobes, prone to motor artefacts, subjects were previously trained in simply using the pointing of their gaze to “point” their level of liking on a picture showing for 5 seconds an horizontal bar, from extreme left (I don’t like it at all) to extreme right (I like it very much). Subjects were asked to choose a point within the bar and fix their gaze on it in order to express their judgements. With the same ratio, a second item about their opinion was related to express in what extend they would be available in buying the product presented in the spot. A second picture showing an horizontal bar was then presented for other 5 seconds, and subjects used again their gaze pointing to express their judgements. In our analyses we attempt to combine the results provided by the two items presented above with the psychophysiological reactions and with the eye-tracking recordings, in order to evaluate the actual reactions of subjects versus their expressed opinions about their level of liking and their level of purchase intentions. The first analysis revealed how the combinations of different physiological signals coupled with eye-tracking recordings might provide information about on one side the level of pleasantness and about the purchase intentions; on the other side, the level of engagement or Flow during the exposure to the 2 adv spots, enabling to rank the 2 adv spots as more or less engaging according to psychophysiological and eye-tracking data