Anxiety Disorders: Brain systems underlying anxiety disorders: a view from neuroimaging

192 Anxiety Disorders: Th eory, Research, and Clinical Perspectives, ed. Helen Blair Simpson, Franklin Schneier, Yuval Neria, Roberto LewisFernández. Published by Cambridge University Press. © Cambridge University Press 2010. inferior frontal (IFC), and temporal cortices; and cerebellum – in short, many of the regions implicated in animal and human studies of emotional experience and emotional learning. It is diffi cult to describe a particular region or set of regions with a simple label, such as “appraisal,” or even “fear.” Th us, instead we adopted a “bottom-up” approach to understanding how these regions assemble into functional networks by grouping them based on their patterns of co-activation. Th at is, if the studies that activated the right IFC were the same studies that activated the left IFC and the dorso-medial PFC (dmPFC), these regions were grouped into a functional network. Th e hope is that these networks may then be related to psychological concepts such as “appraisal” and “anxiety” or map onto physiological processes or action tendencies. Moreover, because our semantic labels may not correspond cleanly with specifi c brain systems, understanding the organization of brain systems in emotion is also a key step towards reformulation of psychological categories to better refl ect brain processes. Our analyses identifi ed a number of networks, shown in Figure 17.1 . Figure 17.1A shows an “unfolded” map of the key brain regions in two dimensions. Each dot is a brain region, and the diff erent colors of the dots indicate the functional groups to which they belong. Th e closer two dots are, the more highly co-activated they are across studies. Lines connecting the dots indicate statistically signifi cant co-activation of the pair of connected regions. Th ese functional groups of regions provide a rudimentary organizational framework for understanding specifi c components of emotional processing. Shown in yellow and magenta in Figure 17.1A is a network involving occipital sensory and association and posterior cingulate cortices, which monitor and analyze the sensory environment. Th ese networks provide input into amygdala and other “core” 17.