Conclusions Historically, emotion and cognition have been viewed as largely separate entities. One way in which emotion has been contrasted with cognition has been to link the former with “irrational”

or “suboptimal” processes127 that are more “basic,” namely more linked to survival, than cognitive ones. Although much has changed in the past two decades, versions of this viewpoint still are quite frequent in the literature (even if, at times, implicitly). Research in the past decades suggests, however, that such view is Inhibitors,research,lifescience,medical likely erroneous and that, in order to understand how complex behaviors are carried out in the brain, an understanding of the interactions between the two is indispensable. Interestingly, neuroimaging in humans may have been one factor contributing to the change in this viewpoint. Because neuroimaging techniques afford whole-brain investigations, it has become increasingly evident that large portions of both cortex and subcortex are engaged during emotional information analyses.128 In many Inhibitors,research,lifescience,medical current formulations of how Inhibitors,research,lifescience,medical emotion is organized in the brain, a heavy emphasis is found on “special” regions, most notably, the amygdala. In particular, it could be argued that the amygdala is “primitive” (in the sense of being derived

from ancestral form), and that it may be better viewed as tied to fear-related functions and as an effective “alarm system” – one that has been evolutionarily conserved for good reasons. Yet, even in rodents important roles for the amygdala in “cognitive” operations, such as attention and decision making, have been documented.129,130

And Inhibitors,research,lifescience,medical in primates, as pointed out by Sander and colleagues, the amygdala may have evolved into a less specialized system in order to cope with new environmental problems.131 One way in which this may have occurred may be related to an expansion of the connectivity of the amygdala with a wider range of cortical territories.132 This Inhibitors,research,lifescience,medical may involve new direct connections, such as the connectivity documented between the amygdala and lateral prefrontal cortex22 and, more extensively, indirect connections via other important much cortical hubs, such as those involving the anterior cingulate, orbitofrontal, and insular cortices. Altered and enhanced connectivity may be one way in which a system expands the repertoire of functions it is involved in. Although the evolution of the brain is highly constrained, dramatic changes in the pattern of connectivity have been documented – such as those involving the somatosensory cortex and thalamus in several mammals.133,134 Furthermore, whereas mice have about 10 cortical fields, and macaque monkeys have more than 50 fields, humans may have more than a hundred fields.134 The combinatorial nature of connectivity is such that, in humans, the amygdala, which is extremely highly interconnected, as reviewed here, may be in a position to be an important player in an learn more impressive array of cognitive-emotional functions.