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Functional grouping and cortical–subcortical interactions in emotion:
A meta-analysis of neuroimaging studies
Hedy Kober,a Lisa Feldman Barrett,b,c Josh Joseph,a Eliza Bliss-Moreau,b
Kristen Lindquist,b and Tor D. Wagera,⁎
aDepartment of Psychology, Columbia University, USA
bDepartment of Psychology, Boston College, USA
cPsychiatric Neuroimaging Research Program, Massachusetts General Hospital, Harvard Medical School, USA
Received 2 November 2007; revised 5 March 2008; accepted 26 March 2008
Available online 11 April 2008
We performed an updated quantitative meta-analysis of 162 neuroima-
ging 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 ourways
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 periaque-
ductal 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, periaque-
ductal 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.
© 2008 Published by Elsevier Inc.
Introduction
In recent years, the number of neuroimaging studies of emotion
has risen dramatically, providing new information on how the
human brain creates emotion. At the time of writing, upwards of 200
neuroimaging studies have investigated the brain correlates of
emotional processing; the general approach is to induce an affective
state and then identify associated patterns of reliable signal increases
in the brain. Affective states are most often categorized into one of
several “discrete emotions” that correspond to English words such as
“anger,” “fear,” “happiness,” and “disgust” or according to broader
affective dimensions, such as hedonic valence (positive/negative),
arousal (high/low), or approach/withdrawal. These studies have
been summarized by several meta-analyses, which have served to
localize the most consistent findings across studies and their
specificity for particular affective states (e.g., Murphy et al., 2003;
Phan et al., 2002; Wager et al., 2003).
One important limiting factor for individual studies and meta-
analyses alike is that the brain–psychological mappings that they
investigate are only as reliable as the categories they employ.
Whether, and under what conditions, affective states can be grouped
meaningfully into discrete categories and/or dimensions is currently
debated (Barrett, 2006a). Perhaps in part because of this limitation,
meta-analyses have not yielded strong evidence that human-defined
categories of emotion can be consistently discerned from neuroima-
ging studies, and there is some inconsistency on this point across
meta-analyses (for a discussion, see Barrett and Wager, 2006).
In this paper, we take a fundamentally different approach: In an
updatedmeta-analysis of 162 neuroimaging studies of emotion (1990–
2005), we use multivariate analyses to identify consistent patterns of
co-activation across studies – which we herein refer to as functional
groups – without reference to their particular affective labels. While
our analyses are still constrained by the nature of the individual studies
that largely employ these affective or emotional labels, the functional
groups that emerge from our analyses are not defined based on
www.elsevier.com/locate/ynimg
NeuroImage 42 (2008) 998–1031
⁎ Corresponding author. Department of Psychology, Columbia University,
1190AmsterdamAvenue, NewYork, NY10027, USA. Fax: +1 212 8543609.
E-mail address: tor@psych.columbia.edu (T.D. Wager).
Available online on ScienceDirect (www.sciencedirect.com).
1053-8119/$ - see front matter © 2008 Published by Elsevier Inc.
doi:10.1016/j.neuroimage.2008.03.059