Subjective rating of emotionally salient stimuli modulates neural activity.
ABSTRACT Studies using emotionally salient stimuli have demonstrated neural activation in limbic and paralimbic brain regions. In some studies, subjects passively perceive evocative stimuli, while in other studies, they perform specific cognitive tasks. Evidence is emerging that even a simple cognitive task performed on emotionally salient stimuli can affect neural activation in emotion-associated brain regions. We tested the hypothesis that rating the subjective experience of an aversive visual stimulus would decrease limbic/paralimbic activation and increase activity in medial frontal regions. Ten healthy subjects underwent (15)O PET scans while they viewed pictures of aversive (AV) and nonaversive (NA) content, taken from the International Affective Picture System. Subjects appraised pictures on a scale of pleasantness/unpleasantness during one set of scans (RTNG), and they passively viewed pictures during another set (PSVW). After each scan, emotional responses were assessed. RTNG was associated with significantly less intensity of sadness and significantly less activation (AV - NA) of the right insula/amygdala and left insula, relative to PSVW. RTNG also activated the dorsal medial prefrontal cortex and the anterior cingulate sulcus, which were not differentially activated during PSVW. For both RTNG and PSVW, subjects activated the left fusiform gyrus. The results support the proposition that task instructions about how subjects should process evocative stimuli can affect neural activity.
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ABSTRACT: Several investigations have shown that emotional events show superior recall than non-emotional ones. However, the cortical mechanisms underlying the episodic recall of emotional scenes are still poorly understood. Our main aim was to compare the mag- nitude of the Event-Related brain Potentials (ERP) old-new effect related to emotionally unpleasant, pleasant and neutral photographic images. As ex- pected, correct recognition of all types of images elicited three topographically distinct ERP components sensitive to the classical old-new recognition effect. The results revealed that the behavioral perform- ances were mainly sensitive to arousal, while the ERP old/new effect over posterior regions (300 - 1000 ms) was exclusively affected by unpleasantness. A later component (1000 - 1400 ms) showed an inverted old/ new effect at parietal sites, which was also sensitive to unpleasantness. These results imply that ERP reflecting episodic conscious recollection and post-re- trieval monitoring are clearly affected both by valence and arousal.World Journal of Neuroscience 01/2013; 03(04):250-262. DOI:10.4236/wjns.2013.34034
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ABSTRACT: The locationist model of affect, which assumes separate brain structures devoted to particular discrete emotions, is currently being questioned as it has not received enough convincing experimental support. An alternative, constructionist approach suggests that our emotional states emerge from the interaction between brain functional networks, which are related to more general, continuous affective categories. In the study, we tested whether the three-dimensional model of affect based on valence, arousal, and dominance (VAD) can reflect brain activity in a more coherent way than the traditional locationist approach. Independent components of brain activity were derived from spontaneous EEG recordings and localized using the DIPFIT method. The correspondence between the spectral power of the revealed brain sources and a mood self-report quantified on the VAD space was analysed. Activation of four (out of nine) clusters of independent brain sources could be successfully explained by the specific combination of three VAD dimensions. The results support the constructionist theory of emotions.Experimental Brain Research 11/2014; 233(3). DOI:10.1007/s00221-014-4149-9 · 2.17 Impact Factor
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ABSTRACT: Although emotional dysfunction is considered a fundamental symptom of schizophrenia, studies investigating the neural basis of emotional dysfunction in schizophrenia are few. Using functional magnetic resonance imaging (fMRI) and a task viewing affective pictures, we aimed to examine automatic emotional response and to elucidate the neural basis of impaired emotional processing in schizophrenia. Fifteen healthy volunteers and 15 schizophrenics were studied. During the scans, the subjects were instructed to indicate how each of the presented pictures made them feel. Whole brain activities in response to the affective pictures were measured by fMRI. Controls recruited the neural circuit including amygdaloid–hippocampal region, prefrontal cortex, thalamus, basal ganglia, cerebellum, midbrain, and visual cortex while viewing unpleasant pictures. Despite an equal behavioral result to controls, the patients showed less activation in the components of the circuit (right amygdala, bilateral hippocampal region, medial prefrontal cortex (MPFC), basal ganglia, thalamus, cerebellum, midbrain, and visual cortex). This study demonstrated functional abnormalities in the neural circuit of emotional processing in schizophrenia. In particular, decreased activation in the right amygdala and MPFC appears to be an important finding related to dysfunctional emotional behavior in schizophrenia.NeuroImage 05/2004; DOI:10.1016/S1053-8119(04)00167-3 · 6.13 Impact Factor