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Ann. N.Y. Acad. Sci., Annals PrePrint, published online ahead of print August 14, 2007 doi: 10.1196/annals.1401.015 Copyright © 2007 by the New York Academy of Sciences description
1 Health Sciences and Program in Neuroscience, Boston University, 635 Commonwealth Ave., , Boston, Massachusetts, 02215, United States
* To whom correspondence should be addressed. E-mail: barbas{at}bu.edu. PrePrint Abstract
The orbitofrontal cortex is associated with encoding the significance of stimuli within an emotional context, and its connections can be understood in this light. This large cortical region is architectonically heterogeneous, but its connections and functions can be summarized by broad grouping of areas by cortical type into posterior and anterior sectors. The posterior (limbic) orbitofrontal region is composed of agranular and dysgranular type cortices, and has unique connections with primary olfactory areas, and rich connections with high-order sensory association cortices. Posterior orbitofrontal areas are further distinguished by dense and distinct patterns of connections with the amygdala and memory-related anterior temporal lobe structures, that may convey signals about emotional import and their memory. The special sets of connections suggest that the posterior orbitofrontal cortex is the primary region for the perception of emotions. In contrast to orbitofrontal areas, posterior medial prefrontal areas in the anterior cingulate are not multi-modal, but have strong connections with auditory association cortices, and brainstem vocalization and autonomic structures, in pathways that may mediate emotional communication and autonomic activation in emotional arousal. Posterior orbitofrontal areas communicate with anterior orbitofrontal areas, and through feedback projections with lateral prefrontal and other cortices, suggesting a sequence of information processing for emotions. Pathology in orbitofrontal cortex may remove feedback input to sensory cortices, dissociating emotional context from sensory content and impairing the ability to interpret events. Key Words:
orbitofrontal connections, laminar patterns of connections, emotions, inhibitory systems, sequential pathways, emotional memory, temporal structures, intercalated amygdalar neurons, anxiety disorders
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