Researchers have wondered how the brain creates emotions since the early days of psychological science. With a surge of studies in affective neuroscience in recent decades, scientists are poised to answer this question. In this article, we present a meta-analytic summary of the human neuroimaging literature on emotion. We compare the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories) to better understand the brain basis of emotion. We review both locationist and psychological constructionist hypotheses of brain–emotion correspondence and report meta-analytic findings bearing on these hypotheses. Overall, we found little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions. Instead, we found evidence that is consistent with a psychological constructionist approach to the mind: a set of interacting brain regions commonly involved in basic psychological operations of both an emotional and non-emotional nature are active during emotion experience and perception across a range of discrete emotion categories.

We performed an updated quantitative meta-analysis of 162 neuroimaging studies of emotion using a novel multi-level kernel-based approach, focusing on locating brain regions consistently activated in emotional tasks and their functional organization into distributed functional groups, independent of semantically defined emotion category labels (e.g., "anger," "fear"). Such brain-based analyses are critical if our ways of labeling emotions are to be evaluated and revised based on consistency with brain data. Consistent activations were limited to specific cortical sub-regions, including multiple functional areas within medial, orbital, and inferior lateral frontal cortices. Consistent with a wealth of animal literature, multiple subcortical activations were identified, including amygdala, ventral striatum, thalamus, hypothalamus, and periaqueductal gray. We used multivariate parcellation and clustering techniques to identify groups of co-activated brain regions across studies. These analyses identified six distributed functional groups, including medial and lateral frontal groups, two posterior cortical groups, and paralimbic and core limbic/brainstem groups. These functional groups provide information on potential organization of brain regions into large-scale networks. Specific follow-up analyses focused on amygdala, periaqueductal gray (PAG), and hypothalamic (Hy) activations, and identified frontal cortical areas co-activated with these core limbic structures. While multiple areas of frontal cortex co-activated with amygdala sub-regions, a specific region of dorsomedial prefrontal cortex (dmPFC, Brodmann's Area 9/32) was the only area co-activated with both PAG and Hy. Subsequent mediation analyses were consistent with a pathway from dmPFC through PAG to Hy. These results suggest that medial frontal areas are more closely associated with core limbic activation than their lateral counterparts, and that dmPFC may play a particularly important role in the cognitive generation of emotional states.

In this article, we discuss the hypothesis that affect is a fundamental, psychologically irreducible property of the human mind. We begin by presenting historical perspectives on the nature of affect. Next, we proceed with a more contemporary discussion of core affect as a basic property of the mind that is realized within a broadly distributed neuronal workspace. We then present the affective circumplex, a mathematical formalization for representing core affective states, and show that this model can be used to represent individual differences in core affective feelings that are linked to meaningful variation in emotional experience. Finally, we conclude by suggesting that core affect has psychological consequences that reach beyond the boundaries of emotion, to influence learning and consciousness."… stimuli do something more than arouse sensation; they give rise to processes of a different kind, to "feelings" in a special sense; we do not merely take the impressions as they come, but we are affected by them, we feel them" Titchener (1909, p. 226) In English, the word "affect" means "to produce a change." To be affected by something is to be influenced by it. In science, and particularly in psychology, "affect" refers to a special kind of influence-something's ability to influence your mind in a way that is linked to your body. Historically, "affect" referred to a simple feeling-to be affected is to feel something. In modern psychological usage, "affect" refers to the mental counterpart of internal bodily representations associated with emotions, actions that involve some degree of motivation, intensity, and force, or even personality dispositions. In the science of emotion, "affect" is a general term that has come to mean anything emotional. A cautious term, it allows reference to something's effect or someone's internal state without specifying exactly what kind of an effect or state it is. It allows researchers to talk about emotion in a theory-neutral way.In this review, we begin with a historical account of the concept of affect in psychology. This sets the stage for discussing the contemporary view of core affect as a basic, universal, and psychologically irreducible property of the mind. We then describe the brain areas that are responsible for realizing core affect, illustrating its central role in mental life. Next, we present the affective circumplex as a mathematical formalization for representing core affective states. We then describe evidence from our own laboratory demonstrating that the circumplex can model and represent individual variation in core affective feelings that are linked to differences in the precision of emotional experience (termed emotional granularity). Finally, we end by describing our most recent research on how affective variation has important psychological NIH Public Access Author ManuscriptAdv Exp Soc Psychol. Author manuscript; available in PMC 2010 June 14. Published in final edited form as:Adv Exp Soc Psychol. 2009 ; 41: 167-218. doi:10.1016/S0065-2601(08)00...

People differ in the extent to which they emphasize feelings of activation or deactivation in their verbal reports of experienced emotion, termed arousal focus (AF). Two multimethod studies indicate that AF is linked to heightened interoceptive sensitivity (as measured by performance on a heartbeat detection task). People who were more sensitive to their heartbeats emphasized feelings of activation and deactivation when reporting their experiences of emotion over time more than did those who were less sensitive. This relationship was not accounted for by several other variables, including simple language effects. Implications for the role of interoception in experienced emotion and the validity of self-reported emotion are discussed.Arousal is a basic property of all affective judgments (for a recent review, see Russell & Feldman Barrett, 1999) and is ubiquitous in models of emotion (e.g.,

For almost 5 decades, the scientific study of emotion has been guided by the assumption that categories such as anger, sadness, and fear cut nature at its joints. Barrett (2006a) provided a comprehensive review of the empirical evidence from the study of emotion in humans and concluded that this assumption has outlived its usefulness. Panksepp and Izard have written lengthy papers (published in this issue) containing complementary but largely nonoverlapping criticisms of Barrett (2006a). In our response, we address three of their concerns. First, we discuss the value of correlational versus experimental studies for evaluating the natural-kind model of emotion and refute the claim that the evidence offered in Barrett (2006a) was merely correlational. Second, we take up the issue of whether or not there is evidence for "coherently organized neural circuits" for natural kinds of emotions in the mammalian brain and counter the claim that Barrett (2006a) ignored crucial evidence for existence of discrete emotions as natural kinds. Third, we address Panksepp and Izard's misconceptions of an alternative view, the conceptual act model of emotion, that was briefly discussed in Barrett (2006a). Finally, we end the article with some thoughts on how to move the scientific study of emotion beyond the debate over whether or not emotions are natural kinds."It would be very surprising indeed if the brain were organized into spatially discrete units that conform to our abstract categorizations of behavior." (Valenstein, 1973, pp. 142-143) According to the National Academy of Sciences in the United States, a theory is a wellsubstantiated explanation of a phenomenon. A theory is the end point of science-it is what scientists know to be true when observations have been confirmed by repeated experimentation (National Academy of Sciences, 1998). A hypothesis, on the other hand, is a tentative statement that must be tested. Barrett (2006a) demonstrated that after a century of empirical research, the natural-kind view of emotion is not yet a theory. It remains a set of hypotheses-or what we might call a model-subject to the same rules of scientific verification as any other model of emotion. It is a fact that people experience phenomena that are called (in English) anger, sadness, and fear. It is a fact that people experience these psychological states as discrete events that are bounded in time and that people often (but not always) experience these states as psychologically distinct from one another. It is also a fact that people easily and effortlessly see anger and sadness and fear in the behaviors of other people, including babies, and in nonhuman animals. People even see these emotions in the behaviors of shapes (squares, circles, and triangles) that move in a particular relation to one another (Heider & Simmel, 1944). It is the task of science to explain these facts: to explain how the events that people experience as anger, sadness, or fear are caused and how they are entailed in the brain. It is compelling to

Summary Contemporary research suggests that the mammalian brain is a complex system, implying that damage to even a single functional area could have widespread consequences across the system. To test this hypothesis, we pharmacogenetically inactivated the rhesus monkey amygdala, a subcortical region with distributed and well-defined cortical connectivity. We then examined the impact of that perturbation on global network organization using resting-state functional connectivity MRI. Amygdala inactivation disrupted amygdalocortical communication and distributed corticocortical coupling across multiple functional brain systems. Altered coupling was explained using a graph-based analysis of experimentally established structural connectivity to simulate disconnection of the amygdala. Communication capacity via monosynaptic and polysynaptic pathways, in aggregate, largely accounted for the correlational structure of endogenous brain activity and many of the non-local changes that resulted from amygdala inactivation. These results highlight the structural basis of distributed neural activity and suggest a strategy for linking focal neuropathology to remote neurophysiological changes.

Three studies assessed the relationship between language and the perception of emotion. The authors predicted and found that the accessibility of emotion words influenced participants' speed or accuracy in perceiving facial behaviors depicting emotion. Specifically, emotion words were either primed or temporarily made less accessible using a semantic satiation procedure. In Studies 1 and 2, participants were slower to categorize facial behaviors depicting emotion (i.e., a face depicting anger) after an emotion word (e.g., "anger") was satiated. In Study 3, participants were less accurate to categorize facial behaviors depicting emotion after an emotion word was satiated. The implications of these findings for a linguistically relative view of emotion perception are discussed.

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