Effects of Positive and Negative Mood Induction on the Prefrontal Cortex Activity Measured by Near Infrared Spectroscopy

Assessing Frontal Lobe Function on Verbal Fluency and Emotion Recall in Autism Spectrum Disorder by fNIRS

This study applied the functional near-infrared spectroscopy (fNIRS) to investigate frontal activity in autism when performing verbal fluency test and emotion recall task. We recruited 32 autistic adults without intellectual disability and 30 typically-developing controls (TDC). Prefrontal hemodynamic changes were evaluated by fNIRS when the participants performed the verbal fluency test and emotion recall task. fNIRS signals in the prefrontal cortex were compared between autism and TDC. Compared to TDC, autistic adults showed comparable performance on the verbal fluency test but exhibited lower frontal activity on the vegetable category. In the verbal fluency test, left frontal activity in TDC significantly increased in the vegetable category (vs. fruit category). In the emotion recall task, left frontal activity increased significantly in TDC when recalling emotional (vs. neutral) events. This increase of left frontal activity on the more difficult works was not found in autism. Similarly, brain activities were related to test performance only in TDC but not in autism. In addition, more severe social deficits were associated with lower frontal activity when recalling emotional events, independent of autism diagnosis. Findings suggested reduced frontal activity in autism, as compared to TDC, when performing verbal fluency tests. The reduction of left frontal activation in verbal fluency test and emotion recall tasks might reflect on the social deficits of the individual. The fNIRS may potentially be applied in assessing frontal lobe function in autism and social deficits in general population. Trial registration number: NCT04010409.

Self-Positivity or Self-Negativity as a Function of the Medial Prefrontal Cortex

Self and emotions are key motivational factors of a person strivings for health and well-being. Understanding neural mechanisms supporting the relationship between these factors bear far-reaching implications for mental health disorders. Recent work indicates a substantial overlap between self-relevant and emotion information processing and has proposed the medial prefrontal cortex (MPFC) as one shared neural signature. However, the precise cognitive and neural mechanisms represented by the MPFC in investigations of self- and emotion-related processing are largely unknown. Here we examined whether the neural underpinnings of self-related processing in the MPFC link to positive or negative emotions. We collected fMRI data to test the distinct and shared neural circuits of self- and emotion-related processing while participants performed personal (self, friend, or stranger) and emotion (happy, sad, or neutral) associative matching tasks. By exploiting tight control over the factors that determine the effects of self-relevance and emotions (positive: Happy vs. neutral; negative: Sad vs. neutral), our univariate analysis revealed that the ventral part of the MPFC (vmPFC), which has established involvement in self-prioritisation effects, was not recruited in the negative emotion prioritisation effect. In contrast, there were no differences in brain activity between the effects of positive emotion- and self-prioritisation. These results were replicated by both region of interest (ROI)-based analysis in the vmPFC and the seed- to voxel functional connectivity analysis between the MPFC and the rest of the brain. The results suggest that the prioritisation effects for self and positive emotions are tightly linked together, and the MPFC plays a large role in discriminating between positive and negative emotions in relation to self-relevance.

Personality Traits Modulate the Impact of Emotional Stimuli During a Working Memory Task: A Near-Infrared Spectroscopy Study

The purpose of the present study was to examine the influence of personality traits on the impact of emotional stimuli focusing on n-back task performance and brain activity changes. Previous neuroimaging studies have reported that individual differences in emotional processing can be attributed to personality traits, which is linked to the hemisphere-specific activity of the dorsolateral prefrontal cortex (DLPFC) in response to emotional stimuli. Thirty right-handed healthy young male participants were recruited in this study and classified into two groups, the behavioral inhibition system (BIS) group and behavioral activation system (BAS) group, based on their scores on the BIS/BAS scale. Participants saw six emotional images (two each with negative, neutral, and positive valence), which were selected from the International Affective Picture System and validated in a preliminary experiment. Then, a dual 2-back task that simultaneously employed auditory-verbal and visuospatial stimuli was conducted. Additionally, the concentration of oxygenated hemoglobin (Oxy-Hb) changes in the DLPFC was measured during the image presentation and dual 2-back task by near-infrared spectroscopy (NIRS). The task performance showed a significantly increased reaction time (RT) in the negative valence independent of personality traits. The results of Oxy-Hb changes showed a significant interaction between personality traits and emotional valence. Further, the hemisphere-subgroup analysis revealed that the right DLPFC activity was significantly higher in the negative valence than in the neutral valence in the BIS group; the right DLPFC activity was also significantly higher in the BIS group than in the BAS group in the positive valence. There was no main effect or interaction in the left DLPFC activity. These findings suggest the importance of considering personality traits when examining the impact of emotional stimuli. Further studies with large sample sizes warranted to examine the influence emotional stimuli exert on working memory performance, considering the personality traits to better understand individual differences in emotional processing.

Sad Music Modulates Pain Perception: An EEG Study

Background

Music has shown positive effects on pain management in previous studies. However, the relationship between musical emotional types and therapeutic effects remains unclear. To investigate this issue, this study tested three typical emotional types of music and discussed their neural mechanisms in relation to pain modulation.

Subjects and Methods

In this experiment, 40 participants were exposed to cold pain under four conditions: listening to happy music, listening to neutral music, listening to sad music and no sound. EEG and pain thresholds were recorded. The participants were divided into the remission group and the nonremission group for analysis. Differences among conditions were quantified by the duration of exposure to the pain-inducing stimulus in the remission group. EEG data were obtained using a fast Fourier transform (FFT) and then correlated with the behavioral data.

Results

We found that sad music had a significantly better effect on alleviating pain, as a result of brain oscillations in a higher beta band and the gamma band at the O2 and P4 electrodes. The comparison between the remission group and the nonremission group suggested that personality may affect music-induced analgesia, and dominance, liveliness and introvert and extrovert personality traits were associated with pain modulation by sad music. Additionally, in the network analysis, we compared brain networks under the three conditions and discussed the possible mechanisms underlying the better analgesic effect of sad music.

Conclusion

Sad music may have a better effect on alleviating pain, and its neural mechanisms are also discussed. This work may help understand the effects of music on pain modulation, which also has potential value for clinical use.

The prefrontal cortex conscious and unconscious response to social/emotional facial expressions involve sex, hemispheric laterality, and selective activation of the central cardiac modulation

The human prefrontal cortex (PFC) processes complex sensory information for the elaboration of social behaviors. The non-invasive neuroimaging technique near-infrared spectroscopy (NIRS) identifies hemodynamic changes and concentration of oxygenated (HbO₂) and deoxygenated (HHb) hemoglobin in the cerebral cortex. We studied the responses detected by NIRS in the right and left PFC activation of 28 participants (n = 14 adult young females and males) while processing social/emotional facial expressions, i.e., in conscious perception of different expressions (neutral, happy, sad, angry, disgust, and fearful) and in unconscious/masked perception of negative expressions (fearful and disgust overlapped by neutral). The power spectral analysis from concomitant ECG signals revealed the sympathetic and parasympathetic modulation of cardiac responses. We found higher HbO₂ values in the right PFC of females than in males during, and in the left PFC after, following the conscious perception of the happy face. In males, the left PFC increased and the right PFC decreased HbO₂ while viewing the happy expression. In both sexes, HHb values were higher during the masked presentation of disgust than fearful expression, and after the masked presentation of fearful expression than during it. Higher sympathetic and lower parasympathetic activity (LF/ HF components) occurred in females when consciously and unconsciously processing negative emotions (p < 0.05 in all cases). These results demonstrate that the human PFC displays a selective activation depending on sex, hemispheric laterality, attention, time for responding to conscious and unconscious emotionally loaded stimuli with simulataneous centrally modulated cardiovascular responses.

What Role Does the Prefrontal Cortex Play in the Processing of Negative and Positive Stimuli in Adolescent Depression?

This perspective describes the contribution of the prefrontal cortex to the symptoms of depression in adolescents and specifically the processing of positive and negative information. We also discuss how the prefrontal cortex (PFC) activity and connectivity during tasks and at rest might be a biomarker for risk for depression onset in adolescents. We include some of our recent work examining not only the anticipation and consummation of positive and negative stimuli, but also effort to gain positive and avoid negative stimuli in adolescents with depression. We find, using region of interest analyses, that the PFC is blunted in those with depression compared to controls across the different phases but in a larger sample the PFC is blunted in the anticipatory phase of the study only. Taken together, in adolescents with depression there is evidence for dysfunctional PFC activity across different studies and tasks. However, the data are limited with small sample sizes and inconsistent findings. Larger longitudinal studies with more detailed assessments of symptoms across the spectrum are needed to further evaluate the role of the PFC in adolescent depression.

Cortical and Autonomic Patterns of Emotion Experiencing During a Recall Task

Abstract. Emotions characterized by opposite valences (positive vs. negative) seem to lead to specific patterns of autonomic and cortical activity. For example, according to valence or approach-withdrawal hypotheses, specific emotions lead to an asymmetrical activation of left or right prefrontal cortex (PFC). The aim of the present study was to explore the psychophysiological underpinnings of emotion experiencing using a paradigm with higher ecological validity than is typically accomplished in neuroimaging research. A total of 28 healthy participants were instructed to recall personally-relevant situations from the past that caused positive (happiness) or negative (anger) emotions, during a 2 min silent preparatory phase and a subsequent 3 min verbal phase. A wearable electrocardiographic (ECG) recording system and a portable 2-channel near-infrared spectroscopy (NIRS) device were used to collect heart rate (HR), high frequencies of heart rate variability (HF-HRV), and the hemodynamic responses of prefrontal cortex during the entire procedure. Results showed that during both anger and happiness recall tasks, HR increased and high frequencies of HRV decreased with respect to the baseline. HR and HF-HRV reached, respectively, their highest and lowest points during the verbal phase of anger recall task. NIRS data evidenced a bilateral increase of oxyhemoglobin concentration changes during both anger and happiness recall tasks, which was highest during the verbal phases. However, no lateralization patterns were found. Overall, present results suggest that the experience of negative emotions, if compared with positive ones, is characterized by a combination of reduced parasympathetic activation and/or increased sympathetic activation. Thus, cardiological data provided partial support to autonomic specificity of emotions. However, the recall paradigm did not evidence an asymmetry of PFC activity during the experience of emotions with opposite valences, probably due to the high number of factors impacting prefrontal activity during a recall paradigm.