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The investigation of neural networks underlying emotion perception and recognition has received considerable attention during the past few years within the affective neuroscience domain. Neuroimaging studies revealed that the prefrontal cortex (PFC) is involved during emotional stimuli comprehension and evaluation, based on stimulus valence and arousal. Nevertheless, the way in which these emotional parameters affect hemodynamic variations has to be clarified. The present study investigated the changes in prefrontal hemodynamic activation by means of an event-related near-infrared spectroscopy (fNIRS) paradigm during the presentation of emotional patterns taken from the International Affective Picture System (IAPS). During the task, 20 subjects (12 females and 8 males) passively viewed neutral, positive and negative emotional images, which could also be low or high arousing (20 stimuli for each category). Stimuli were presented for 6 s in a randomized order, with 12s inter- stimulus interval. Hemodynamic and electrocortical (EEG) activities were simultaneously recorded from 6 NIRS and 16 EEG channels, in the same session. Changes in oxygenated (oxyHb) and deoxygenated (deoxyHb) hemoglobin were measured with respect to the different experimental conditions. Results showed that the emotional valence of the picture modulates the activation of the PFC, with increased activity for negative patterns and decreased activity for positive ones, if compared to neutral condition. Moreover, preliminary analyses revealed a consonance between EEG (frequency band oscillations) and hemodynamic responses. In conclusion, the present study revealed that prefrontal blood oxygenation and brain oscillations are differently modulated by the emotional content mainly related to the stimulus valence, and demonstrated that the PFC is involved in emotional processing.

Negli ultimi decenni le neuroscienze hanno mostrato un interesse crescente nello studio della capacità di elaborazione delle emozioni e nella comprensione dei meccanismi neurali che supportano tali processi. Questo contesto scientifico ha contribuito allo sviluppo di modelli esplicativi dell’elaborazione emozionale che spiegano il diverso reclutamento corticale in relazione alla valenza dello stimolo e della lateralizzazione emisferica. Tuttavia resta da chiarire il ruolo esercitato dall’emisfero destro e sinistro nei processi di valutazione, interpretazione e regolazione emotiva, nonché il rapporto che sussiste con meccanismi espliciti di valutazione cognitiva. Scopo del presente studio è quello di indagare la presenza di una possibile relazione sistematica tra variazioni emodinamiche e meccanismi di appraisal associati al riconoscimento di pattern emotivi. I soggetti hanno eseguito un compito di riconoscimento emotivo tramite la presentazione di immagini IAPS, selezionate in base a valenza e arousal. Gli indici emodinamici sono stati rilevati mediante functional Near-Infrared Spectroscopy (fNIRS), al fine di verificare eventuali fenomeni di laterizzazione e coupling interemisferico nel riconoscimento emotivo. Inoltre si chiedeva ai partecipanti di valutare gli stimoli presentati rispetto alla dicotomia valenza-arousal, su scala likert a 5 passi (SAM). L'analisi dei dati, su indici correlazionali, ha mostrato che è possibile associare pattern emodinamici differenti in relazione ai diversi pattern comportamentali di valutazione. Nello specifico si osserva una relazione tra il profilo emodinamico della corteccia prefrontale e la valutazione self-report espressa dai partecipanti per le immagini emotive in relazione alla valenza delle stesse. I risultati mostrano un diverso intervento della corteccia prefrontale nella fase di elaborazione di stimoli emotivi correlabile al profilo di risposta comportamentale valenza-relata.

Il recente interesse per le neuroscienze affettive ha permesso di individuare, attraverso studi di neuroimmagine funzionale, il ruolo della corteccia prefrontale (PFC) nei processi di elaborazione e regolazione emotiva. Nonostante le numerose evidenze a supporto dei dati di imaging, rimane ancora da chiarire il rapporto che sussiste tra manifestazioni emodinamiche, elettrofisiologiche ed autonomiche periferiche legate al processamento emotivo, secondo un’ottica integrata. In questo contesto è stato sviluppato un paradigma fNIRS (functional Near-Infrared Spectroscopy) evento-relato, in coregistrazione EEG e rilevazione autonomica (arousal-correlati), che prevedeva la presentazione di immagini emotive (IAPS) selezionate in base ai punteggi di valenza e arousal. A conclusione del compito era richiesta la valutazione degli stimoli e la compilazione della scala BIS/BAS (indici psicometrici) per la misura di componenti personologiche. I dati emodinamici sono stati acquisiti mediante un sistema di rilevazione “in continua” (CW: continuous-wave), con un montaggio prefrontale a 6 canali. Dai risultati è emerso che la presentazione d’immagini emotive si associa a una maggiore attivazione della PFC rispetto alle immagini neutre, e che il profilo di risposta emodinamica varia in base alla valenza dello stimolo. In particolare, durante la presentazione di immagini negative, si osserva una maggiore attivazione della PFC, con un aumento nel livello di O2Hb e un decremento nel livello di HHb. Un pattern opposto emerge, invece, per le immagini a valenza positiva. Queste evidenze sono state interpretate in relazione ai dati neurofisiologici, autonomici e psicometrici. I risultati hanno confermato la presenza di un coinvolgimento prefrontale durante la presentazione di immagini emotive e suggeriscono il vantaggio di un approccio metodologico integrato per lo studio di fenomeni complessi come quelli legati al processamento emotivo.

The present study explored the effect of lateralized left–right resting brain activity on prefrontal cortical responsiveness to emotional cues and on the explicit appraisal of emotions based on their valence. Indeed, subjective response to different emotional stimuli should be predicted by brain resting activity, should be lateralized, and valence-related (positive vs. negative valence). Hemodynamic measure was considered (functional Near-Infrared Spectroscopy, fNIRS). NIRS resting activity and brain response to emotional cues were registered when subjects viewed emotional positive vs. negative stimuli (IAPS). LIR (Lateralized Index Response) during resting state, LI (Lateralized Index) during emotional processing and SAM rating were considered. Regression analysis showed the significant predictive effect of resting activity (more left or right lateralized) on both brain response and appraisal of emotional cues based on stimulus valence. Moreover, significant effects were found as a function of valence (more right response to negative stimuli; more left response to positive stimuli) during emotion processing. Therefore, resting state may be considered a predictive marker of the successive cortical responsiveness and appraisal of emotions.

This study explored the effect of lateralized left-right resting brain activity on prefrontal cortical responsiveness to emotional cues and on the explicit appraisal (stimulus evaluation) of emotions based on their valence. Indeed subjective responses to different emotional stimuli should be predicted by brain resting activity and should be lateralized and valence-related (positive vs negative valence). A hemodynamic measure was considered (functional near-infrared spectroscopy). Indeed hemodynamic resting activity and brain response to emotional cues were registered when subjects (N = 19) viewed emotional positive vs negative stimuli (IAPS). Lateralized index response during resting state, LI (lateralized index) during emotional processing and self-assessment manikin rating were considered. Regression analysis showed the significant predictive effect of resting activity (more left or right lateralized) on both brain response and appraisal of emotional cues based on stimuli valence. Moreover, significant effects were found as a function of valence (more right response to negative stimuli; more left response to positive stimuli) during emotion processing. Therefore, resting state may be considered a predictive marker of the successive cortical responsiveness to emotions. The significance of resting condition for emotional behavior was discussed.

Due to its fast temporal evolution and its representation and integration among complex and widespread neural networks, the emotion perception process should preferably be examined by means of multimethodological approach. Indeed the indubitable vantage of acquiring both the autonomic (arousal-related) and the central (cortical-related) activities stands in the possibility to better elucidate the reciprocal interplay of the two compartments. In the present study EEG (frequency band analysis), systemic SCR and heart rate (HR) were all recorded simultaneously with hemodynamic (NIRS, Near-Infrared Spectroscopy) measurements as potential biological markers of emotions, related to both central and peripheral systems. These multiple measures were then related to the self-report correlates, that is the subjective appraisal in term of valence (positive vs. negative) and arousal (high vs. low) by using SAM rating. Twenty subjects were submitted to emotional cues processing (IAPS) when fNIRS, frequency bands (alpha, beta, delta, theta), SCR and HR were recorded. As shown by O2Hb increasing within the right hemisphere, the contribution of prefrontal cortex was elucidated, by pointing out a relevant lateralization effect (more right-PFC activity) induced by the specific valence (negative) of the emotional patterns. Secondly, EEG activity (mainly low-frequency theta and delta bands) was intrinsically associated with the cortical hemodynamic responsiveness to the negative emotional patterns, within the right side. Finally SCR increased mainly in response to negative patterns, and the autonomic behavior was related to explicit (SAM) and cortical (NIRS; EEG) activity. The intrinsic relationships between these three different levels are discussed.