Article

Effective Connectivity within the Distributed Cortical Network for Face Perception

Institute of Neuroradiology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Cerebral Cortex (Impact Factor: 8.67). 11/2007; 17(10):2400-6. DOI: 10.1093/cercor/bhl148
Source: PubMed

ABSTRACT

Face perception elicits activation within a distributed cortical network in the human brain. The network includes visual ("core") regions, as well as limbic and prefrontal ("extended") regions, which process invariant facial features and changeable aspects of faces, respectively. We used functional Magnetic Resonance Imaging and Dynamic Causal Modeling to investigate effective connectivity and functional organization between and within the core and the extended systems. We predicted a ventral rather than dorsal connection between the core and the extended systems during face viewing and tested whether valence and fame would alter functional coupling within the network. We found that the core system is hierarchically organized in a predominantly feed-forward fashion, and that the fusiform gyrus (FG) exerts the dominant influence on the extended system. Moreover, emotional faces increased the coupling between the FG and the amygdala, whereas famous faces increased the coupling between the FG and the orbitofrontal cortex. Our results demonstrate content-specific dynamic alterations in the functional coupling between visual-limbic and visual-prefrontal face-responsive pathways.

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    • "Thus, our study provides empirical evidence for dynamic alterations in neural coupling during the perception of behaviorally relevant facial expressions that are vital for social communication and interaction. DCM studies of face perception in the human brain suggest differential modulation of neural coupling by emotion, particularly among the FG, amygdala, and prefrontal cortex (Fairhall and Ishai 2007;Dima et al. 2011;Herrington et al 2011). Our current results suggest homologies between monkeys and humans in the neural circuits mediating the response to emotional faces. "
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    ABSTRACT: In humans and monkeys, face perception activates a distributed cortical network that includes extrastriate, limbic, and prefrontal regions. Within face-responsive regions, emotional faces evoke stronger responses than neutral faces ("valence effect"). We used fMRI and Dynamic Causal Modeling (DCM) to test the hypothesis that emotional faces differentially alter the functional coupling among face-responsive regions. Three monkeys viewed conspecific faces with neutral, threatening, fearful, and appeasing expressions. Using Bayesian model selection, various models of neural interactions between the posterior (TEO) and anterior (TE) portions of inferior temporal (IT) cortex, the amygdala, the orbitofrontal (OFC), and ventrolateral prefrontal cortex (VLPFC) were tested. The valence effect was mediated by feedback connections from the amygdala to TE and TEO, and feedback connections from VLPFC to the amygdala and TE. Emotional faces were associated with differential effective connectivity: Fearful faces evoked stronger modulations in the connections from the amygdala to TE and TEO; threatening faces evoked weaker modulations in the connections from the amygdala and VLPFC to TE; and appeasing faces evoked weaker modulations in the connection from VLPFC to the amygdala. Our results suggest dynamic alterations in neural coupling during the perception of behaviorally relevant facial expressions that are vital for social communication.
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    • ", 1994 ; Ishai et al . , 2005 ; Fairhall and Ishai , 2007 ) . According to the model proposed by Haxby et al . "
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    ABSTRACT: Face perception is mediated by a distributed brain network comprised of the core system at occipito-temporal areas and the extended system at other relevant brain areas involving bilateral hemispheres. In this study we explored how the brain connectivity changes over the time for face-sensitive processing. We investigated the dynamic functional connectivity in face perception by analyzing time-dependent EEG phase synchronization in four different frequency bands: theta (4-7 Hz), alpha (8-14 Hz), beta (15-24 Hz), and gamma (25-45 Hz) bands in the early stages of face processing from 30 to 300 ms. High-density EEG were recorded from subjects who were passively viewing faces, buildings, and chairs. The dynamic connectivity within the core system and between the extended system were investigated. Significant differences between faces and non-faces mainly appear in theta band connectivity: (1) at the time segment of 90-120 ms between parietal area and occipito-temporal area in the right hemisphere, and (2) at the time segment of 150-180 ms between bilateral occipito-temporal areas. These results indicate (1) the importance of theta-band connectivity in the face-sensitive processing, and (2) that different parts of network are involved for the initial stage of face categorization and the stage of face structural encoding.
    Full-text · Article · Dec 2015 · Frontiers in Human Neuroscience
    • "That is, age-dependent amygdala reactivity during reappraisal was significantly accounted for by age-dependent changes in left fusiform gyrus activation , such that in younger participants, heightened fusiform activation accounted for reduced amygdala downregulation . The association between fusiform and amygdala activation is consistent with results from emotional face tasks, which suggest that the fusiform face area is an important feed-forward modulator of amygdala respond- ing[Fairhall and Ishai, 2007;Pujol et al., 2009]. Indeed, the strength of functional coupling of these regions during reappraisal (versus look-negative) was found to be negatively associated with age, highlighting the possibility that such feed-forward modulation may be greater among younger participants. "
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    ABSTRACT: Few studies have examined the neural correlates of emotion regulation across adolescence and young adulthood. Existing studies of cognitive reappraisal indicate that improvements in regulatory efficiency may develop linearly across this period, in accordance with maturation of prefrontal cortical systems. However, there is also evidence for adolescent differences in reappraisal specific to the activation of "social-information processing network" regions, including the amygdala and temporal-occipital cortices. Here, we use fMRI to examine the neural correlates of emotional reactivity and reappraisal in response to aversive social imagery in a group of 78 adolescents and young adults aged 15-25 years. Within the group, younger participants exhibited greater activation of temporal-occipital brain regions during reappraisal in combination with weaker suppression of amygdala reactivity-the latter being a general correlate of successful reappraisal. Further analyses demonstrated that these age-related influences on amygdala reactivity were specifically mediated by activation of the fusiform face area. Overall, these findings suggest that enhanced processing of salient social cues (i.e., faces) increases reactivity of the amygdala during reappraisal and that this relationship is stronger in younger adolescents. How these relationships contribute to well-known vulnerabilities of emotion regulation during this developmental period will be an important topic for ongoing research. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Nov 2015 · Human Brain Mapping
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