170,058 research outputs found
The role of reward and inhibitory systems in subliminal and supraliminal processing of facial expression of emotions. Brain research contribution
No full textIn comprehension of facial expression of emotions behavioural activation system (BAS) and behavioural inhibition system (BIS) was considered as an explicative factor to verify the effect of motivational/reward variable on cortical brain activity. Brain oscillation modulation, that is alpha band variation, was monitored within right-and left-cortical side when subjects consciously (supraliminal stimulation) or unconsciously (subliminal stimulation) processed facial patterns. The unconscious effect of an emotional stimulus was highlighted by a vast amount of research, whereas it remains questionable whether it is possible to assign a specific function to cortical oscillations in unconscious perception of facial expressions of emotions. Twenty subjects looked at six facial expressions of emotions (anger, fear, surprise, disgust, happiness, sadness, and neutral) in two different conditions: supraliminal (200 ms) vs subliminal (30 ms) stimulation (140 target-mask pairs for each condition). The results showed that both conscious and unconscious processing and significance of the stimulus can modulate the alpha power. Moreover, it was found an increased right frontal activity for negative, aversive emotions vs. an increased left response for positive emotion. Finally, whereas higher BIS subjects generated a more right hemisphere activation for negative emotions (mainly fear, anger, surprise, and disgust), BAS subjects were more responsive to positive emotion (happiness) within left hemisphere. Significance of facial expressions was adduced to elucidate cortical different responses to emotional types. © 2012 Nova Science Publishers, Inc. All rights reserved
Left DLPFC rTMS stimulation reduced the anxiety bias effect or how to restore the positive memory processing in high-anxiety subjects
No full textIn the present research we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory retrieval process of positive vs. negative emotional stimulus, as a function of the anxiety levels. Anxiety behavior showed a consistent attentional bias toward negative and aversive memories, induced by a right frontal cortical superiority. This effect was analyzed by using a rTMS paradigm that induced a cortical activation of the left DLPFC. Subjects, who were divided in two different groups depending on their anxiety level (high/low-anxiety, State-Trait-Anxiety-Inventory, STAI), were required to perform a task consisting of two experimental phases: an encoding-phase, where some lists composed by positive and negative emotional words were presented to the subjects; and a retrieval-phase, where the old stimuli and new stimuli were presented for a recognition performance. We found that the rTMS stimulation affects the memory retrieval of emotional material. High-anxiety subjects benefit in greater measure from the left DLPFC stimulation with a reduced negative bias. This result suggested that left DLPFC activation favors the memory retrieval of positive emotional information and might limit the "unbalance effect" induced by a right hemispheric superiority at a high level of anxiety. The potentiality of TMS for anxiety behavior modulation was also discussed. © 2013 Elsevier Ireland Ltd
RTMS stimulation on left DLPFC increases the correct recognition of memories for emotional target and distractor words
No full textAccording to a recent hypothesis, the prefrontal cortex has been proposed as the site of emotional memory integration, because it is sensitive to the recognition of emotional contents. In the present research, we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory recognition processes for positive versus negative emotional stimuli when old (target) and new (distractor, either semantically related or unrelated to the target) stimuli were presented. The role of the DLPFC was analysed using an rTMS (repeated transcranial magnetic stimulation) paradigm that induced increased cortical activation of the left DLPFC. The subjects were required to perform a task that consisted of two experimental phases (i.e., an encoding and a recognition phase) in which the targets and the distractors were presented and recognition performance was measured. rTMS stimulation was provided over the left DLPFC during the recognition phase. We found that the rTMS stimulation affected the memory recognition of positive emotional material. Moreover, related and unrelated distractors were discarded better when they were positively valenced, and a more significant effect (i.e., increased performance) was produced in response to related distractors. This result suggests that the activation of the left DLPFC favours the memory recognition of positive emotional information, and that such activation is able to induce a more appropriate selective process to distinguish target from distractor stimuli in the presence of more complex processes (related distractors). The valence model of emotional cue processing may explain this increased performance by demonstrating the distinct role of the left hemisphere in the retrieval of positive emotional information. © Psychonomic Society, Inc. 2012
DLPFC implication in memory processing of affective information. A look on anxiety trait contribution
No full textRecent studies suggested to approach to the analysis of the emotions and cognition from an integrating point of view rather than investigate the two constructs per se. In line with this research approach, the present study aims to investigate how emotions can affect memory processes and which cerebral areas are involved in this mechanism. We also aim to understand if and how this processing is influenced by specific personality traits, as anxiety trait. Using a rTMS measure, participants were asked to performance a memory task (a retrieval task) composed by verbal material with and without emotional content. Subjects were also assessed for their anxiety trait (high and low anxiety subjects). Our study provided a strong evidence for the influence of the emotional content and personality trait on the memory processes. Secondly, the role of the Left Dorso-Lateral Prefrontal Cortex in emotional memory was pointed out with a specific function ofthisfiontal network in managing the emotional memories
Aversive vs. Appetitive emotional stimulus elaboration. Subjective ratings and BIS and BAS effects on psychophysiological and ERPs correlates
No full textThe effect of subjective evaluation on arousal and valence dimensions, on one hand, and of the individual differences related to BIS and BAS (Behavioural Inhibition and Activation System) measure, on the other, were considered in response to appetitive and aversive emotional stimuli. Multiple measures were recorded, such as psychophysiological (skin conductance response, heart rate, and electromyography) and ERPs responses, during viewing IAPS figures, that varied in terms of pleasantness (appetitive vs. aversive) and arousing power (high vs. low intensity). Autonomic variables and two ERP positivities (P3 and LPP) were found to be modulated by valence and arousal rating, with an increased response for high arousing and negative or positive stimuli in comparison with low arousing and neutral stimuli. Moreover, BAS subjects were more responsive to positive than negative emotions, whereas BIS subjects responded in greater measure to negative and arousing emotions. The effects of subjective evaluation and individual differences were discussed at light of biphasic model of emotion comprehension. © 2012 Nova Science Publishers, Inc. All rights reserved
EEG correlates (event-related desynchronization) of emotional face elaboration : a temporal analysis
No full textAn EEG frequency band analysis was conducted, in order to explore the significance of brain oscillations (delta, theta, alpha and beta) for emotional face comprehension during different post-stimulus time intervals (50-150; 150-250; 250-350; and 350-450 ms). The study was conducted on twenty adults who looked at emotional (happy, sad, angry, fearful) or neutral faces. The results showed that motivational significance of the stimulus can modulate the power synchronization (event-related desynchronization (ERD) decrease) within the frequency band of delta and theta. We propose that delta and theta respond to variations in processing stage of emotional face: whereas, delta reflects updating of the stimulus, theta responds to the emotional significance of face. The findings revealed that emotional discrimination by theta is observable mainly within 150-250 time interval and that it is more distributed on anterior regions, whereas delta is maximally synchronized within 250-350 interval and more posteriorly distributed for all the stimulus type. Finally, a right-hemisphere dominance was found for theta during emotional face comprehension
Subliminal and supraliminal processing of facial expression of emotions: Brain oscillation in the left/right frontal area
No full textThe unconscious effects of an emotional stimulus have been highlighted by a vast amount of research, whereover it remains questionable whether it is possible to assign a specific function to cortical brain oscillations in the unconscious perception of facial expressions of emotions. Alpha band variation was monitored within the right- and left-cortical side when subjects consciously (supraliminal stimulation) or unconsciously (subliminal stimulation) processed facial patterns. Twenty subjects looked at six facial expressions of emotions (anger, fear, surprise, disgust, happiness, sadness, and neutral) under two different conditions: supraliminal (200 ms) vs. subliminal (30 ms) stimulation (140 target-mask pairs for each condition). The results showed that conscious/unconscious processing and the significance of the stimulus can modulate the alpha power. Moreover, it was found that there was an increased right frontal activity for negative emotions vs. an increased left response for positive emotion. The significance of facial expressions was adduced to elucidate cortical different responses to emotional types. © 2012 by the authors; licensee MDPI, Basel, Switzerland
Consciousness and arousal effects on emotional face processing as revealed by brain oscillations. A gamma band analysis
No full textIt remains an open question whether it is possible to assign a single brain operation or psychological function for facial emotion decoding to a certain type of oscillatory activity. Gamma band activity (GBA) offers an adequate tool for studying cortical activation patterns during emotional face information processing. In the present study brain oscillations were analyzed in response to facial expression of emotions. Specifically, GBA modulation was measured when twenty subjects looked at emotional (angry, fearful, happy, and sad faces) or neutral faces in two different conditions: supraliminal (10 ms) vs subliminal (150 ms) stimulation (100 target-mask pairs for each condition). The results showed that both consciousness and significance of the stimulus in terms of arousal can modulate the power synchronization (ERD decrease) during 150–350 time range: an early oscillatory event showed its peak at about 200 ms post-stimulus. GBA was enhanced by supraliminal more than subliminal elaboration, as well as more by high arousal (anger and fear) than low arousal (happiness and sadness) emotions. Finally a left-posterior dominance for conscious elaboration was found, whereas right hemisphere was discriminant in emotional processing of face in comparison with neutral face
RTMS stimulation on left dlpfc affects emotional cue retrieval as a function of anxiety level and gender
No full textBackground Anxiety behaviour showed a consistent attentional bias toward negative and aversive memories, induced by a right dorsolateral prefrontal cortex (DLPFC) hyperactivation. In the present research, we explored the possible effect of rTMS (repeated transcranial magnetic stimulation) on the left DLPFC in memory retrieval of positive versus negative emotional words, to induce a balanced response between the two hemispheres. Moreover, the gender effect in emotional memory processing was verified as a function of the stimulus valence. Methods Thirty subjects, who were divided in two different groups depending on their anxiety level (high/low anxiety, State-Trait-Anxiety Inventory (STAI)), were required to perform a task consisting of two experimental phases: An encoding phase (lists composed by positive and negative emotional words); and a retrieval phase (old stimuli and new stimuli to be recognized). Results We found that the rTMS stimulation over left DLPFC affects the memory retrieval. Specifically, high-anxiety subjects benefitted in greater measure to the frontal left stimulation with a reduced negative bias (increased accuracy and reduced response time (RT) for the positive stimuli). Whereas females showed a significant bias toward the negative memories, they did not benefit in greater measure to the TMS stimulation on the left hemisphere. Conclusion These results suggested that left DLPFC activation favors the memory retrieval of positive emotional information and may limit the "unbalance effect" induced by a right frontal hemispheric superiority in high levels of anxiety. © 2012 Wiley Periodicals, Inc
Consciousness and emotional facial expression recognition: subliminal/supraliminal stimulation effect on N200 and P300 ERPs
No full textIn this study we analyze whether facial expression recognition is marked by specific event-related potential (ERP) correlates and whether conscious and unconscious elaboration of emotional facial stimuli are qualitatively different processes. ERPs elicited by supraliminal and subliminal (10ms) stimuli were recorded when subjects were viewing emotional facial expressions of four emotions or neutral stimuli. Two ERP effects (N2 and P3) were analyzed in terms of their peak amplitude and latency variations. An emotional specificity was observed for the negative deflection N2, whereas P3 was not affected by the content of the stimulus (emotional or neutral). Unaware information processing proved to be quite similar to aware processing in terms of peak morphology but not of latency. A major result of this research was that unconscious stimulation produced a more delayed peak variation than conscious stimulation did. Also, a more posterior distribution of the ERP was found for N2 as a function of emotional content of the stimulus. On the contrary, cortical lateralization (right/left) was not correlated to conscious/unconscious stimulation. The functional significance of our results is underlined in terms of subliminal effect and emotion recognition
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