John A. King, R. James R. Blair, Derek G.V. Mitchell, Raymond J. Dolan and Neil Burgess
NeuroImage, in press
Humans have a considerable facility to adapt their behavior in a manner that is appropriate to social or societal context. A failure of this ability can lead to social exclusion and is a feature of disorders such as psychopathy and disruptive behavior disorder. We investigated the neural basis of this ability using a customized video game played by 12 healthy participants in an fMRI scanner. Two conditions involved extreme examples of context-appropriate action: shooting an aggressive humanoid assailant or healing a passive wounded person. Two control conditions involved carefully matched stimuli paired with inappropriate actions: shooting the person or healing the assailant. Surprisingly, the same circuit, including the amygdala and ventromedial prefrontal cortex, was activated when participants acted in a context-appropriate manner, whether being compassionate towards an injured conspecific or aggressive towards a violent assailant. The findings indicate a common system that guides behavioral expression appropriate to social or societal context irrespective of its aggressive or compassionate nature.
Monday, November 28, 2005
Saturday, November 12, 2005
ARTICLE UPDATE - How brains beware: neural mechanisms of emotional attention
Patrik Vuilleumier
Trends in Cognitive Sciences, in press
Emotional processes not only serve to record the value of sensory events, but also to elicit adaptive responses and modify perception. Recent research using functional brain imaging in human subjects has begun to reveal neural substrates by which sensory processing and attention can be modulated by the affective significance of stimuli. The amygdala plays a crucial role in providing both direct and indirect top-down signals on sensory pathways, which can influence the representation of emotional events, especially when related to threat. These modulatory effects implement specialized mechanisms of ‘emotional attention’ that might supplement but also compete with other sources of top-down control on perception. This work should help to elucidate the neural processes and temporal dynamics governing the integration of cognitive and affective influences in attention and behaviour.
Trends in Cognitive Sciences, in press
Emotional processes not only serve to record the value of sensory events, but also to elicit adaptive responses and modify perception. Recent research using functional brain imaging in human subjects has begun to reveal neural substrates by which sensory processing and attention can be modulated by the affective significance of stimuli. The amygdala plays a crucial role in providing both direct and indirect top-down signals on sensory pathways, which can influence the representation of emotional events, especially when related to threat. These modulatory effects implement specialized mechanisms of ‘emotional attention’ that might supplement but also compete with other sources of top-down control on perception. This work should help to elucidate the neural processes and temporal dynamics governing the integration of cognitive and affective influences in attention and behaviour.
Wednesday, November 09, 2005
ARTICLE UPDATE - Dissociable networks for the expectancy and perception of emotional stimuli in the human brain
Felix Bermpohl, Alvaro Pascual-Leone, Amir Amedi, Lotfi B. Merabet, Felipe Fregni, Nadine Gaab, David Alsop, Gottfried Schlaug and Georg Northoff
NeuroImage, in press
William James posited that comparable brain regions were implicated in the anticipation and perception of a stimulus; however, dissociable networks (at least in part) may also underlie these processes. Recent functional neuroimaging studies have addressed this issue by comparing brain systems associated with the expectancy and perception of visual, tactile, nociceptive, and reward stimuli. In the present fMRI study, we addressed this issue in the domain of pictorial emotional stimuli (IAPS). Our paradigm involved the experimental conditions emotional expectancy, neutral expectancy, emotional picture perception, and neutral picture perception. Specifically, the emotional expectancy cue was uncertain in that it did not provide additional information regarding the positive or negative valence of the subsequent picture. Neutral expectancy and neutral picture perception served as control conditions, allowing the identification of expectancy and perception effects specific for emotion processing. To avoid contamination of the perception conditions by the preceding expectancy periods, 50% of the pictorial stimuli were presented without preceding expectancy cues. We found that the emotional expectancy cue specifically produced activation in the supracallosal anterior cingulate, cingulate motor area, and parieto-occipital sulcus. These regions were not significantly activated by emotional picture perception which recruited a different neuronal network, including the amygdala, insula, medial and lateral prefrontal cortex, cerebellum, and occipitotemporal areas. This dissociation may reflect a distinction between anticipatory and perceptive components of emotional stimulus processing.
NeuroImage, in press
William James posited that comparable brain regions were implicated in the anticipation and perception of a stimulus; however, dissociable networks (at least in part) may also underlie these processes. Recent functional neuroimaging studies have addressed this issue by comparing brain systems associated with the expectancy and perception of visual, tactile, nociceptive, and reward stimuli. In the present fMRI study, we addressed this issue in the domain of pictorial emotional stimuli (IAPS). Our paradigm involved the experimental conditions emotional expectancy, neutral expectancy, emotional picture perception, and neutral picture perception. Specifically, the emotional expectancy cue was uncertain in that it did not provide additional information regarding the positive or negative valence of the subsequent picture. Neutral expectancy and neutral picture perception served as control conditions, allowing the identification of expectancy and perception effects specific for emotion processing. To avoid contamination of the perception conditions by the preceding expectancy periods, 50% of the pictorial stimuli were presented without preceding expectancy cues. We found that the emotional expectancy cue specifically produced activation in the supracallosal anterior cingulate, cingulate motor area, and parieto-occipital sulcus. These regions were not significantly activated by emotional picture perception which recruited a different neuronal network, including the amygdala, insula, medial and lateral prefrontal cortex, cerebellum, and occipitotemporal areas. This dissociation may reflect a distinction between anticipatory and perceptive components of emotional stimulus processing.
ARTICLE UPDATE - Changes in effective connectivity during incidental and intentional perception of fearful faces
G. de Marco, M. de Bonis, P. Vrignaud, M.C. Henry-Feugeas and I. Peretti
NeuroImage, in press
The present fMRI study examined effective connectivity within an emotional network composed of three brain areas: Amygdala (AMY), Anterior Cingulate Cortex (AAC) and Orbito-Frontal (OFC) in processing fearful faces. Two tasks: an incidental perception (gender identification) and an intentional detection (effortful discrimination) task were performed by 14 and 10 young healthy volunteers, respectively. Participants were scanned while viewing fearful, neutral and ambiguous facial expressions. Effective connectivity was assessed using Structural Equation Modeling (SEM). Results show that the hypothetical network fits the experimental data for both tasks and in both hemispheres. The comparison between Tasks 1 and 2 reveals significant differences in strength and direction of the connectivity patterns for the left and to a less stringent threshold for the right hemisphere. The path coefficients analysis suggests that the fearful information generated in AMY, reaches the OFC through the ACC in incidental perception, while in intentional perception, the route followed is in a reverse direction from OFC to ACC. Our findings confirm a differential brain connectivity between incidental and intentional processing of fearful faces.
NeuroImage, in press
The present fMRI study examined effective connectivity within an emotional network composed of three brain areas: Amygdala (AMY), Anterior Cingulate Cortex (AAC) and Orbito-Frontal (OFC) in processing fearful faces. Two tasks: an incidental perception (gender identification) and an intentional detection (effortful discrimination) task were performed by 14 and 10 young healthy volunteers, respectively. Participants were scanned while viewing fearful, neutral and ambiguous facial expressions. Effective connectivity was assessed using Structural Equation Modeling (SEM). Results show that the hypothetical network fits the experimental data for both tasks and in both hemispheres. The comparison between Tasks 1 and 2 reveals significant differences in strength and direction of the connectivity patterns for the left and to a less stringent threshold for the right hemisphere. The path coefficients analysis suggests that the fearful information generated in AMY, reaches the OFC through the ACC in incidental perception, while in intentional perception, the route followed is in a reverse direction from OFC to ACC. Our findings confirm a differential brain connectivity between incidental and intentional processing of fearful faces.
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