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Regret and its avoidance: a neuroimaging study of
choice behavior
Giorgio Coricelli
1
, Hugo D Critchley
2
, Mateus Joffily
1
, John P O’Doherty
2
, Angela Sirigu
1
& Raymond J Dolan
2
Human decisions can be shaped by predictions of emotions that ensue after choosing advantageously or disadvantageously.
Indeed, anticipating regret is a powerful predictor of future choices. We measured brain activity using functional magnetic
resonance imaging (fMRI) while subjects selected between two gambles wherein regret was induced by providing information
about the outcome of the unchosen gamble. Increasing regret enhanced activity in the medial orbitofrontal region, the anterior
cingulate cortex and the hippocampus. Notably, across the experiment, subjects became increasingly regret-aversive, a cumulative
effect reflected in enhanced activity within medial orbitofrontal cortex and amygdala. This pattern of activity reoccurred just
before making a choice, suggesting that the same neural circuitry mediates direct experience of regret and its anticipation. These
results demonstrate that medial orbitofrontal cortex modulates the gain of adaptive emotions in a manner that may provide a
substrate for the influence of high-level emotions on decision making.
Cost-benefit analyses in everyday decision making are often difficult
because our evidence about future outcomes is incomplete or, at
best, probabilistic. According to standard economic theory, rational
decision makers should optimize their choice strategies through
reliance on expected utility. However, it is known that human decisions
deviate from this ideal and are influenced by other, less rational,
considerations. For instance, the Dutch postal code lottery is popular,
although playing the lottery can be considered an irrational behavior.
Its success has been explained by the possibility that people anticipate
how bad they would feel if, not having bought a ticket, their postal
code is drawn.
A sense of responsibility in human decision making operates
through a process of counterfactual reasoning
1,2
that enables us to
relate the outcome of a previous decision with what we would have
obtained had we opted for a rejected alternative. Regrets are what we
experience when this comparison is to our disadvantage
3–6
, and it can
be defined as a cognitively enriched emotion embodying a feeling of
responsibility for negative outcomes of choices
7,8
. This contrasts with
disappointment, which is an emotion related to an unexpected negative
outcome, without an obligatory sense of personal responsibility
9,10
.As
regret is an unpleasant feeling that encapsulates a sense of responsi-
bility, we learn from past experience to minimize its likely reoccurrence
when considering a new choice decision
11
.
The interplay between decision making and emotional processing
can be assumed to involve a contribution from several brain structures,
including areas associated with executive and emotional processing.
Several lines of evidence indicate that orbitofrontal cortex (OFC)
assigns relative value to stimuli and updates the salience of primary
and secondary reinforcers
12–14
. Both simple and abstract complex
instrumental reinforcers such as monetary gain and loss evoke
emotions that serve to guide behavior, and the OFC is a
candidate substrate for the generation of such emotions
15–18
.We
would also suggest that the OFC modulates the gain of emotions
using a top-down process in which a paradigmatic cognitive process,
specifically counterfactual thinking, contributes to an emotional
response and ensuing choice behavior. Evidence that high-level emo-
tions such as regret depend on a specific neuroanatomical substrate
comes from a study showing that the normal expression of this
cognitively based emotion depends on the integrity of OFC
19
.Speci-
fically, patients with selective lesions to anterior medial OFC do not
experience regret and, unlike healthy controls, are unable to adjust their
behavior to avoid regret-inducing situations. In order to define pre-
cisely the conditions under which the OFC and related areas are
engaged by the experience and anticipation of regret and to determine
how the latter experience influences learning, we used functional
magnetic resonance imaging (fMRI) while subjects performed a
gambling task. We demonstrated that activity in the OFC mediates
the experience of adaptive emotions such as regret. Moreover, learning
to anticipate this emotion during choice reactivated the OFC in
conjunction with the amygdala.
On each trial, the subject viewed two gambles where different
probabilities involving financial gain or loss were represented by the
relative size of colored sectors of a circle (Fig. 1). There were two kinds
of trials, each with a different type of feedback information indicating
financial gain or loss for the subject. In the ‘partial feedback’ condition,
only the outcome of the selected gamble was shown, whereas in the
‘complete feedback’ condition, the outcome of both the selected and
unselected gambles were available to the subject. Complete feedback
Published online 7 August 2005; doi:10.1038/nn1514
1
Neuropsychology Group, Institut des Sciences Cognitives, Centre National de la Recherche Scientifique, 67 Boulevard Pinel 69675, Bron, France.
2
Wellcome Department
of Imaging Neuroscience, 12 Queen Square, London, WC1N 3BG, UK. Correspondence should be addressed to R.J.D. (rdolan@fil.ion.ucl.ac.uk) or A.S. (sirigu@isc.cnrs.fr).
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trials enabled subjects to judge not only the financial consequence of
their decision but also the outcome they would have achieved had they
selected the unselected option.
As a sense of responsibility is critical to the experience of regret, we
compared subjects’ responses when they had a choice (the ‘choose’
condition) with their responses when they had no choice, but rather
followed a computer-selected choice (the ‘follow’ condition), thus
removing any feeling of responsibility.
RESULTS
Ventral striatum response to wins and losses
Agency is reflected in cognitive and physiological engagement of
subjects. During task performance, subjects’ physiological responses
(heart rate) were significantly higher in ‘choose’ trials than in ‘follow’
trials (P ¼ 0.001). During fMRI, the processing of outcome was
modulated as a function of whether outcome (wins or losses) was
evaluated in the context of a ‘choose’ or ‘follow’ trial (that is, whether
subjects were agents). We found activation of anterior ventral striatum
during wins and a relative deactivation during losses solely in ‘choose’
trials (Fig. 2), highlighting the dependency of reward-related signaling
in this region on instrumentality
20
. This pattern of activity in ventral
striatum for ‘choose’ trials is consistent with a ‘reward prediction error’
response
21
insofar as in ‘follow’ trials (where choice was computer-
selected, meaning the subject had no agency) there is no need for
prediction
22
. In other words, this area processes mismatches between
predicted and actual outcome and is activated when an outcome is
better than expected and relatively deactivated in the alternative case. In
light of this agency effect, we restricted our subsequent analyses of
outcome-related activity to ‘choose’ trials alone.
Disappointment and regret
The psychological and behavioral impact of outcome (wins and losses)
was influenced by the amount of feedback information provided to
subjects. Disappointment arises when, on a selected gamble, the
alternative outcome is more positive than an experienced outcome.
The magnitude of disappointment (that is, the discrepancy between the
‘unobtained outcome’ and actual outcome of the selected gamble
correlated with enhanced activity in middle temporal gyrus and dorsal
brainstem (including periaqueductal gray matter), a region implicated
in processing aversive signals such as pain
23
(Ta ble 1 a).
Regret represents an emotion based on counterfactual processing,
but it differs from disappointment in its abstract point of reference.
At outcome
2.0 s
2.0 s
4.0 s
4.0 s
1.0 s
At choice
Analysis of imaging data
CC
CF
'Choose'
'Choose'
'Follow'
'Follow'
Complete
feedback
feedback
PC
PF
Partial
1.0 s
4.0 s
4.0 s
2.0 s
2.0 s
12 + 1 (dummy)
trials per run
16 runs divided in
two sections: A & B
200 –200 –5050 200 –200 –5050 200 –200 –5050
200 –200 –5050 200 –200 –5050 200 –200 –5050
Trial 12Trial 11Trial 2Trial 1 Dummy
PC CC PF CF CC PF PC CF PF CC CF PC CF PF PC CC
Ventral striatum
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
Win Loss Win Loss
Choose Follow
Relative % change in
BOLD signal
VStr VStr
Figure 1 Experimental design. On each trial, the
subject viewed two gambles where different
probabilities of financial gain or loss were
represented by the relative size of colored sectors
of a circle. The preferred gamble was indicated by
the subject by means of a left or right button
press. Once selected, the chosen gamble was
highlighted on the screen by a green square. A
rotating arrow then appeared in the center of the
gamble circle, stopping after 4 s. The outcome of
the selected gamble, indicated by the resting
position of the arrow, resulted in financial gain or
loss for the subject. Half of the trials were ‘choose’
trials; in half of those, only the outcome of the
selected gamble was given to the subject (‘partial
feedback choose’, PC). In the other half, the
outcome of both selected and unselected gambles
were available (‘complete feedback choose’, CC).
An equal number of trials were ‘follow’ trials, in
which the subject was informed that the computer
would randomly choose one of the two gambles. A
green square appeared behind one of the two
gambles, and the subject had to press a button on
the corresponding side. Follow trials were likewise
divided into complete feedback (‘complete
feedback follow’, CF) and partial feedback (‘partial
feedback follow’, PF) trials.
Figure 2 Activity at outcome is related to win and loss. Activity within the
striatum, encompassing regions of ventral striatum, discriminated between
financial gain and loss at trial outcome. This effect, however, was significant
only for ‘choose’ trials, in which the subject was responsible for the choice
(that is, when the subject rather than the computer selected between two
gambles). Group data (thresholded at P o 0.001, uncorrected) is plotted on
sagittal and coronal sections of a normalized canonical template brain.
Striatal activations (VStr) were centered on MNI coordinates (8, 18, 0),
(6, 18, 2) and (12, 24, 8). The bottom panel plots the average parameter
estimates (± s.e.m.) for relative difference in BOLD activity at outcome for
wins and losses in ‘choose’ and ‘follow’ trials.
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Regret arises from a discrepancy between the actual outcome and an
outcome that would have pertained had an alternative choice been
taken. In our experiment, regret is represented as the difference between
the outcome of the unselected gamble and the outcome of the selected
gamble; hence, it occurs only on complete feedback trials. Across both
win and loss trials, the magnitude of the difference in unselected and
selected outcomes correlated with enhanced activity within anterior
cingulate, putamen, inferior parietal lobule (which is implicated in
processing number comparison
24
) and lateral OFC (Ta bl e 1 b).
Effect of the unobtained outcome
Activity in medial OFC clearly discriminated between trials resulting in
a win or a loss, but only in the complete feedback condition (Fig. 3). We
modeled the corresponding outcome of the nonselected gamble as a
parametric regressor for each outcome (win or loss); in partial feedback
trials, we used the unobtained outcome of the chosen gamble as a
parametric regressor. By adopting such a procedure, we could dis-
sociate comparative assessments underlying counterfactual thinking.
The counterfactual process in the complete feedback condition in
losing trials resulted in greater activation of bilateral regions of medial
OFC, and greater deactivation for winning trials. Notably, in this
analysis, losses in the complete feedback condition resulted in the
emotion of regret (with the exception of the case in which the subject
lost 50 and felt relief at forgoing an outcome of 200), whereas wins
resulted in relief (with the exception of the case in which the subject
won 50 and felt regret for a forgone outcome of +200; Fig. 3).
Activity in medial OFC, extending from subgenual cingulate, corre-
lated with the degree of regret (that is, the difference between the
outcome of the unchosen gamble and the obtained outcome) in the
‘choose’/complete feedback condition (referred to as the ‘complete
choose’ condition). These data are plotted in Figure 4a, showing the
change in magnitude of the fitted response in OFC relative to the degree
of regret and relief experienced. In addition, anterior hippocampus
activity correlated with regret. From this analysis, we extracted data on
brain activity in response to the obtained outcomes of 50 and +50 as
a function of the outcome of the unselected gamble (200 and +200)
in the complete feedback condition (Fig. 4b). Notably, activity in the
OFC, dorsal anterior cingulate cortex (ACC) and anterior hippo-
campus discriminated between the two unobtained outcomes.
More specifically, these areas were activated when the actual outcome
was compared with a more advantageous forgone outcome (+200),
leading to regret, and are relatively deactivated when the same
actual outcome is compared with a less advantageous alternative
(200), leading to relief. Self-reported emotional ratings (in the
practice session before scanning) were consistent with this result in
that the ratings did not simply reflect wins or losses on the selected
gambles but rather were strongly influenced by the provision of
information regarding outcome of the alternative nonselected gamble
(Fig. 4c). These results suggest that there are three main regions that
contribute to the experience of regret: dorsal anterior cingulate cortex,
medial OFC and anterior hippocampus.
Choice behavior and brain activity
During the fMRI experiment, we predetermined the presentation of
individual gambles and the outcome of each gamble such that subjects
were exposed, in both ‘choose’ and ‘follow’ trials, to a range of positive
and negative outcomes and, for complete feedback trials, were exposed
to alternative outcomes that provided either positive and negative
values. However, for ‘choose’ trials, the selection of individual gambles
was determined by the subject, and the individual behavior in this
pattern of selection provided data on subject sensitivity to wins and
losses and counterfactual information.
It is indeed counterfactual thinking between the obtained and the
unobtained outcomes that modulates the experience of regret and
disappointment. When the subject obtains an outcome that is lower
than expected, he or she might feel disappointment. The greater the
difference between the expected and the obtained outcome, the more
intense is this negative feeling. Thus, the subject can avoid future
disappointment by choosing a gamble that minimizes a difference
between lowest and highest outcome, weighted by the probability of the
worst possible outcome.
We tested a model of choice (see Methods) using the data from the
partial-feedback/‘choose’ condition (the ‘partial choose’ condition)
that incorporated the effects of anticipating disappointment in addi-
tion to the maximization of the expected values. The result from a
regression analysis (Ta bl e 2a ) shows that subjects chose maximizing
Table 1 Activity at outcome
(a) Activity related to the comparison between the unobtained and the obtained
outcome of the selected gamble (‘partial choose’ condition)
Location Side Coordinates Z-score
Midbrain (periaqueductal gray region) – 2, 34, 20 3.84
Precentral gyrus S2 L 60, 4, 8 3.74
Subcallosal gyrus L 4, 0, 8 3.61
Middle temporal gyrus L 42, 0, 20 3.54
(b) Activity related to the comparison between the outcome of the unselected gamble
and the obtained outcome of the selected gamble (‘complete choose’ condition)
Anterior cingulate cortex – 10, 24, 34 4.68
Putamen L –14, 0, 6 3.92
Lateral OFC R 42, 42, –18 3.77
Inferior parietal lobule R 54, –50, 36 3.67
Win Loss Win Loss
PartialComplete
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
Relative % change in
BOLD signal
Orbitofrontal cortex
OFC
Figure 3 The effect of the unobtained outcome: counterfactual processing of
value. Orbitofrontal cortex (OFC) activity for the comparison between the
outcome of the selected gamble and the alternative outcome in the ‘complete
choose’ versus ‘partial choose’ conditions (right). For the ‘complete choose’
condition we modeled the corresponding outcome of the nonselected gamble
as a parametric regressor for each actual outcome (win or loss), whereas in
partial feedback trials, we used the unobtained outcome of the chosen
gamble as a parametric regressor. The counterfactual process between losses
(or wins) and any forgone outcome in the complete condition resulted in
much greater activation (or deactivation) of bilateral regions of medial OFC.
Error bars indicate s.e.m. In the partial feedback condition, we observed only
a relative deactivation of the OFC when actual losses were compared with
unobtained outcome in the chosen gamble. Group data (thresholded at P o
0.001, uncorrected) is plotted on an axial section of a normalized canonical
template brain (left panel). Peak orbitofrontal activity occurred at MNI
coordinates (8, 32, 14).
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expected values (P o 0.001) and minimizing future disappointment
(P ¼ 0.001). Notably, brain activity in motor and premotor cortex,
anterior cingulate cortex and superior parietal cortex related to a pre-
ceding choice of maximal expected value (Table 3a). Choice behavior
that deviates from the maximization of expected values, motivated by
avoidance of future disappointment, produced activity in the substan-
tia nigra, a dopaminergic midbrain area involved in anticipatory
reward (reward prediction, refs. 25,26; Supplementary Figure 1).
This activity is related to the activity at outcome observed when
subjects evaluated wins and loss in terms of prediction error (Fig. 2).
The feeling of regret depends on the comparison between the
obtained and the unobtained outcome across the two gambles, a
comparison possible only in the complete feedback condition. The
greater the difference between the outcome of the unchosen gamble
and the obtained outcome, the more intense the feeling of regret. We
parameterized regret as the absolute value of the difference between the
lowest and the highest outcome across gambles. Thus, the subject can
avoid future regret by choosing a gamble that minimizes this difference
(see equation 3 in Methods). In our analysis of subjects’ behavior in the
complete choose condition, we considered anticipated disappointment,
anticipated regret and maximization of the expected values as the main
components of subjects’ choices. Results from a regression analysis
–50 +50
–50 +50–50 +50–50 +50
Obtained outcomeObtained outcomeObtained outcomeObtained outcome
1
3
5
7
9
Very bad
Very good
Emotional evaluation
–200
+200
–200
+200
Unobtained
outcome
Unobtained
outcome
–0.5
0.0
0.5
Relative % change in
BOLD signal
Relative % change in
BOLD signal
OFC ACC Hippocampus
11223344
Regret →← Relief
–0.4
–0.2
0.0
0.2
0.4
0.6
0.8
Data across subjects
OFC
ab c
Figure 4 Regret and relief. (a) Change in magnitude of fitted response in the medial OFC relative to the degree of regret or relief experienced in the CC
condition. Medial OFC activity (10, 30, 12) correlates with the level of regret experienced. Regret and relief are measured as the positive and negative
differences, respectively, between the outcome of the unselected gamble and the actual outcome. The relative change in BOLD signal between unobtained
and actual outcomes is plotted for each of the four levels of regret (numbered 1–4, from lowest to highest regret). The first value in each pair representsthe
unobtained outcome and the second value represents the actual outcome: 1: [50, 50]; 2: [200, 50], [50, 200]; 3: [200, 50], [50, 200]; and 4:
[200, 200]. The four levels of relief are the result of the following comparisons (numbered 1–4, as for regret): 1: [50, 50]; 2: [200, 50], [50, 200]; 3:
[200, 50], [50, 200]; and 4: [200, 200]. (b) Left plot: medial OFC activity; center: anterior cingulate cortex activity (coordinates 8, 32, 24); and right:
hippocampal activity (30, 10, 12) in processing the comparison between 50 and +50 obtained with a forgone outcome of 200 or + 200 in the CC
condition. Error bars, s.e.m. (c) Mean emotional evaluation (± s.e.m.) measured in the practice session before scanning for two obtained outcomes (50 or 50)
as a function of the outcome of the unchosen gamble (200 or 200) in the complete feedback condition.
Table 2 Regression analysis (panel logit procedure with individual
random effect)
(a) Subjects’ choice behavior as a function of anticipated disappointment (d)and
maximization of the expected value (e) in the ‘partial choose’ condition.
Variable name Coefficient Standard error ZP
Constant 0.22014 0.13002 1.69 0.09
d 0.00259 0.0008 3.23 0.001
e 0.01464 0.00106 13.79 0.000
Number of subjects ¼ 15;numberofobservations¼ 720. Log likelihood ¼331.4631,
Wald w
2
(2) ¼ 193.71, Prob 4w
2
¼ 0.000. The dependent variable ‘choice’ is equal to 1 if
subject chose gamble 1 and equal to 0 if subject chose gamble 2.
(b) Subjects’ choice behavior as a function of anticipated disappointment (d),
maximization of the expected value (e) and anticipated regret (r) in the ‘complete
choose’ condition.
Variable name Coefficient Standard error ZP
Constant 0.06958 0.09706 0.72 0.473
d 0.00211 0.00137 1.62 0.106
r 0.00463 0.00114 4.03 0.000
e 0.00726 0.00184 3.94 0.000
Number of subjects ¼ 15;numberofobservations¼ 720. Log likelihood ¼331.1425;
Wald w
2
(3) ¼ 205.82, Prob 4w
2
¼ 0.000. The dependent variable ‘choice’ is equal to 1
if subject chose gamble 1 and is equal to 0 if subject chose gamble 2.
Table 3 Activity at choice
(a) Activity preceding choice of maximal expected values in the ‘partial choose’
condition
Location Side Coordinates Z-score
Motor cingulate cortex L 12, 10, 46 4.85
Premotor cortex L 34, 20, 62 4.08
Motor/posterior cingulate cortex R 14, 28, 54 4.43
Genual anterior cingulate cortex R 18, 36, 8 4.04
Superior parietal cortex R 42, 52, 52 3.73
(b) Activity preceding choice of maximal expected values in the ‘complete choose’
condition
Lateral occipital cortex L 38, 76, 64.43
Lateral geniculate nucleus L 20, 31, 6 3.89
Somatomotor cortex L 28, 28, 52 3.98
Superior parietal cortex R 24, 56, 50 3.96
Parahippocampus L 32, 2, 26 3.29
Mid cingulate cortex – 6, 4, 32 4.36
(c) Influence of cumulative experience of regret (CR) on choice-related activity
Somatomotor cortex R 68, 12, 20 5.19
Inferior parietal lobule L 38, 42, 40 4.8
Medial OFC L 10, 40, 24 4.24
Amygdala L 8, 4, 24 4.21
(d) Influence of immediately prior experience of regret (t –1)onchoice
Dorsolateral prefrontal cortex R 46, 28, 38 4.99
Lateral OFC R 42, 26, 16 4.72
Inferior parietal lobule R 54, 58, 48 4.62
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(panel logit procedure with individual random effect, Ta ble 2b)show
that subjects chose maximizing expected values (P o 0.001) and
minimizing future regret (P o 0.001).
Anticipating disappointment (as defined in equation 2 in Methods)
would correspond to risk avoidance. The absence of this behavior (as
shown in Ta b l e 2 b for the variable d, P ¼ 0.11) in the complete choose
condition indicates a hierarchical relationship between risk and regret.
Indeed, the subjects chose minimizing regret independently of the risk
component in their choice responses.
How the experience of regret affects decision making
The experience of regret has a powerful influence on subsequent
behavioral choice, leading to a pattern of behavior that can be
characterized as regret-aversive. In our experiment, this was manifest
in two distinct ways. First, we observed a behavioral bias in subjects’
choices over the course of the gambling task away from choices that
mightengenderanemotionofregret(Table 2 b ). Second, regret aversion
was also evident in a bias away from choices that had previously led to
negative outcomes, on the basis of subjects’ own cumulative experience
of regret. The proportion of regret-avoiding choices increased over time
with the cumulative effect of the experience of regret (Fig. 5a).
On the basis of the above data, we determined how these behavioral
biases were expressed in patterns of neural activity at the time of
choice behavior. We found enhanced activity (during the epoch
between trial onset and subject response in the complete choose
condition) in the dorsal anterior cingulate cortex and in the substantia
nigra, when subjects chose minimizing regret over maximizing
expected values (Supplementary Figure 2). Both anterior cingulate
and midbrain activities are related to a reward anticipation process (in
terms of error prediction signal)
25–28
. Activity related to a preceding
choice of maximal expected values in the ‘complete choose’ condition is
shown in Ta bl e 3 b.
We next assessed the effects of cumulative history using a reinforce-
ment-learning model based on past emotional experience (see Meth-
ods). For cumulative regret experience, we observed modulation of
choice-related activity in the medial OFC,
right somatomotor, inferior parietal lobule
and left amygdala (Fig. 5b and Ta ble 3c).
Notably, this expression of cumulative regret
at the time of decision making involved simi-
lar anatomical regions (medial OFC and ante-
rior medial temporal lobe) as that elicited by
regret at the time of outcome feedback. This
suggests that the experience-dependent influ-
ence of regret on decision making may be
supported by reactivation of processes med-
iating regret as a reactive emotion.
The more immediate experience of regret
in the preceding trial also influenced choice-
related activity, enhancing responses in right
dorsolateral prefrontal cortex, particularly
around the border between middle and infer-
ior frontal gyri, perhaps representing an influ-
ence of immediate regret on self-monitoring
at decision making. We also found that
enhanced activity during choice selection in
right inferior parietal lobule and right caudo-
lateral OFC correlated similarly with the mag-
nitude of regret experienced in the preceding
trial (Tabl e 3d and Fig. 5c).
DISCUSSION
Regret is a complex emotion based on a counterfactual process that
juxtaposes the outcome of choices we make with a better outcome for a
rejected alternative. We show that activity in response to this negative
emotion is distinct from activity seen for mere outcome evaluation. In
our brain imaging data, the influence of personal responsibility on the
processing of outcome was evident in contrasting outcome-related
activity for ‘choose’ trials (where the subject selected which gamble to
‘play’) with ‘follow’ trials (where the ‘choice’ was computer-selected).
In accordance with psychological theory
5,11
, we also find a neuroana-
tomical dissociation of regret versus disappointment. Thus, outcome
evaluation is influenced by the level of responsibility in the process of
choice (agency) and by the available information regarding alternative
outcomes (complete or partial feedback). The level of regret, calculated
in terms of the magnitude of the difference between the forgone
outcome and the obtained outcome, was strongly correlated with
activity in the medial OFC.
In a number of studies (including tasks in which outcome is not
dependent on operant action) medial OFC activity reflects reward
attainment
17,18,29,30
. This has been interpreted as suggesting that
medial OFC may support positive emotions (and that lateral OFC
may support emotions with negative valence). Nevertheless, other
neuroimaging studies highlight a more complex role in reinforcement
representations that is also suggested by lesion data. Thus, enhance-
ment of medial OFC activity reflects devaluation in extinction
of conditioned aversive stimuli and inflation of aversive stimuli
12
.
Significant activity with monetary gain and loss has been reported in
both medial and lateral OFC
31
, whereas monetary gain in a probabil-
istic reversal task has been associated with activity in both medial and
lateral OFC. Similarly, lesions of medial OFC do not impair processing
of primary rewards but seem to interfere with relative reward dis-
crimination that includes conditions involving prospective and coun-
terfactual appraisal
19,32
. These findings point to a more complex
relationship in OFC than a simple medial-lateral specialization for
reward or punishment. Our data would suggest that cognitive context,
DLPFC
DLPFC
IPL
OFC
OFC
Amg
FinalMiddleInitial
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Proportion
Anticipated regret
Blocks
ab
c
Figure 5 Activity at choice: learning from the experience of regret. (a) Proportion of choice (± s.e.m.)
related to anticipated regret in ‘complete choose’ trials. Anticipated regret increased over time as the
experiment proceeded. (b) Activity at choice reflecting cumulative regret. We found activity in the medial
left amygdala (Amg; coordinates 8to16, 4, 25) and medial OFC (10, 40, 24). Group data is
plotted on coronal and axial slices of a template brain in normal space at a threshold of P o 0.005,
uncorrected (for illustrative purposes in this figure only). (c) Activity reflecting prior regret at choice.
Individual subject analytic designs modeled the parametric modulation of activity during the epoch
between trial onset and subject response. Experience of regret in the preceding trial profoundly
influenced choice-related activity, enhancing responses in right dorsolateral prefrontal (DLPFC),
right lateral OFC, and inferior parietal lobule (IPL; Table 3c). Group activity is plotted at
P o 0.001, uncorrected.
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exemplified by counterfactual thinking in relation to states of the world,
exerts a modulatory influence on OFC activation to reward and
punishment. On this basis, our neuroimaging data complement and
confirm results from lesion studies
19
that assign a critical role to the
medial OFC in experiencing and anticipating the emotion of regret.
To our knowledge, this is the first demonstration of involvement of
medial OFC and amygdala in choice behavior that reflects regret
avoidance. We suggest that, as a result of cumulative experience of
regret, inputs from these regions to decision-making processes provide
an updated representation of value that incorporates a weighting of the
relative emotional value of different options for choice
12,33
. In addition,
there is enhanced lateral OFC activity in the choice condition that
immediately follows the experience of regret, perhaps reflecting cogni-
tive processes associated with a need (across gamble comparisons) to
avoid future regrettable outcomes. Such processes are analogous to
those normally subsumed under procedures involving reversal learn-
ing, where subjects need to change behavioral strategies that are no
longer advantageous
34
. We also found enhanced activity in the parietal
cortex during choice selection, in accordance with findings in animal
studies related to action desirability
35
. Thus, the experience of regret
has a major impact on the process of choice that is expressed at two
levels, with a net result of biasing subjects to forgo choices that might
lead to future experience of this highly negative emotion.
Regret is also an emotion based on a declarative cognitive process
that requires an ability to assess the consequences of our actions within
conscious awareness. It is not surprising that there is involvement of
brain structures such as the hippocampus and dorsal anterior cingulate
regions that are critical to declarative memory (indicating what we
need to remember) and cognitive-induced arousal responses, respec-
tively
36,37
. Dorsal anterior cingulate activity is related to the experience
of regret at outcome and to regret-aversive decision making at choice.
In the context of decision making, regret involves an appraisal of
potential outcomes and is likely to evoke behavioral adjustments on
subsequent trials. Indeed, choice behavior in our complete task involves
either maximizing expected value in the face of potential regret, or
minimizing regret at a cost to expected value. Thus, the decision
process necessarily involves a degree of conflict. There is substantial
neuroimaging literature that highlights a role for dorsal anterior
cingulate and pre-supplementary motor area in response monitoring
and error detection
38–41
. Notably, dorsal anterior cingulate cortex
activity may also mediate an attentional focus on subjective emotional
states
42,43
and the cognitive and emotional processing engendered in
states of autonomic arousal
44,45
. Our findings would conform to a
unified model of error detection, response conflict and attendant
emotional arousal whereby anterior cingulate activation arises during
appraisal of conflicts (between maximizing expected value and mini-
mizing regret) in decision making that would include a signal for
potential behavioral adjustment.
However, the critical finding in our study concerns the role of OFC,
which we suggest integrates cognitive and emotional mechanisms after
a declarative process in which distinct counterfactual processes engen-
der a high-level emotion of regret. Our data suggest a mechanism by
which comparing a choice with its alternative outcome, along with the
associated feeling of responsibility, promotes behavioral flexibility and
exploratory strategies in dynamic environments so as to minimize the
likelihood of emotionally negative outcomes.
METHODS
Subjects. Fifteen healthy right-handed subjects were recruited to take part in a
study at the Wellcome Department of Imaging Neuroscience. These volunteers
gave fully informed consent for the project which was approved by the Joint
Ethics Committee of the National Hospitals and Institute of Neurology,
London. Each participant was screened to exclude medication and conditions
including psychological or physical illness or history of head injury. Mean age
of participants was 23.3 years.
Experimental design and task. Each participant underwent fMRI scanning
while performing a total of 192 trials of the experimental task illustrated in
Figure 1. During scanning, the subject viewed a projection of a computer
screen and made a two-choice button-press response with the right index or
middle finger. The task was adapted from refs. 5 and 19 and involved stimuli
resembling ‘wheels of fortune’. On each trial, the subject viewed two gambles
where different probabilities of financial gain or loss were represented by the
relative size of colored sectors of a circle.
Half the trials were designated ‘choose’ trials in which the preferred gamble
was indicated by the subject by means of a left or right button press. Once
selected, the chosen gamble was highlighted on the screen by a green square,
and a rotating arrow then appeared in the center of the gamble circle, stopping
after 4 s. The outcome of the selected gamble, indicated by the resting position
of the arrow, resulted in financial gain or loss. There were two kinds of choose
trials: in 48 of the 96 ‘choose’ trials, the outcome (and the spinning arrow)
appeared for the selected gamble alone (‘partial feedback’). In the other 48
‘choose’ trials, the spinning arrow and outcome of both the selected and
unselected gambles were visible to the subject (‘complete feedback’). Complete
feedback trials enabled the subject to judge not only the financial consequence
of their decision, but also the outcome had they selected the other option.
An equal number of trials were designated ‘follow’ trials, which were also
divided into complete and partial feedback trials. In ‘follow’ trials, the subject
was informed that the computer would randomly choose one of the two
gambles. A green square appeared behind one of the two gambles, and the
subject was required to press the corresponding button. The rotating arrow
then appeared, as in the ‘choose’ condition, in the selected gamble circles (or in
both circles, for the complete feedback condition), stopping to indicate the
outcome. The ‘follow’ condition was a control condition, as it eliminated the
responsibility element of decision making but still produced outcomes repre-
senting financial gains and losses.
Partial and complete feedback and ‘choose’ and ‘follow’ conditions were
presented in pseudo-randomized blocks of 12 stimuli. Null events were also in-
cluded in each block to allow estimation of low-level baseline brain activity and
to desynchronize timings of event types. Behavioral responses were logged by
means of a desktop computer running Cogent software on a Matlab platform.
Incentive procedure. Each subject was told that the outcome of both ‘choose’
and ‘follow’ trials would result in financial gain or loss. The subjects were
informed before starting the experiment that they would be paid a show-up fee
of 20 GBP and an additional amount that would depend on their performance
in terms of cumulative points earned during the experiment, in both ‘choose’
and ‘follow’ conditions: 0 GBP, 5 GBP and 10 GBP corresponded to low,
medium and high cumulative earnings, respectively. No quantitative references
about the ranges of the cumulative earnings were provided. The subjects were
informed about their earnings and paid in cash outside the fMRI scanner. No
information about their cumulative outcomes was provided during the
experiment. For ethical reasons, we were not able to pay different amounts
to subjects; thus, in practice we programmed the computer to always assign 5
extra GBP. Every subject ended up with final earnings of 25 GBP.
Parameter structure. Each individual gamble presented paired combinations of
200, 50, 50 and 200 points and represented one of three levels of outcome
probability (0.2, 0.5 and 0.8). Displayed and actual probabilities were identical.
The two gambles always differed in their expected values (that is, probability
times the outcome of each alternative choice) and in the value of their actual
outcomes. There were six possible outcome pairs (outcome obtained in the
chosen gamble and outcome of the unselected gamble, or vice versa): (i) 50
and 200, (ii) 50 and 200, (iii) 50 and 200, (iv) 50 and 200, (v) 50 and 50
and (vi) 200 and 200. The set of pairs of gambles was the same for each
condition. The order of presentation was pseudo-random and differed for each
condition. In the ‘follow’ condition, the predetermined pattern of choices did
not resemble any particular choice strategy. The set of trials and the computer’s
pattern of choice in ‘follow’ conditions can be found in Supplementary Table 1.
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Emotional rating. Before scanning, the subject read a standard description of
the task and was familiarized with the computerized task events. The subject
then performed a practice session covering the four trial types (‘complete
choose’, ‘partial choose’, ‘complete follow’ and ‘partial follow’) and were asked
to rate how they felt about each outcome on a nine-point scale (where 9
signaled a very good outcome and 1 very bad).
Physiological monitoring. Blood volume pressure (BVP) was recorded with a
Nonin 8600 Pulse Oximeter (Nonin Medical) and sampled at 300 Hz at the
same time as task performance and fMRI data acquisition. BVP signal and
fMRI scanning pulses were coregistered by means of an analog-to-digital
converter (CED1901) and Spike 3.3 software (CED). Heart rate was estimated
from BVP inter-beat intervals and resampled at 2 Hz for later analysis. We
considered physiological responses in each trial of two time windows of 3 s
each. The first time window (anticipatory) started when the stimulus was
presented at the beginning of each trial and included the choice (or follow)
event and the period of waiting for the outcome; the second time window
(feedback) corresponded to the feedback presentation.
Analysis of behavioral data. We tested (by regression analysis and the panel
logit procedure with individual random effect; Ta ble 2 ) a model of choice that
incorporates the effects of anticipating disappointment and regret in addition
to maximization of expected values. x
1
and y
1
represent the highest and the
lowest outcome of gamble 1 (g
1
), and x
2
and y
2
represent the highest and the
lowest outcome of gamble 2 (g
2
). The probability of x
1
is p and the probability
of y
1
is 1 – p; the probability of x
2
is q, and the probability of y
2
is 1 – q.The
probability of choosing gamble 1 is
Prðg
1it
Þ¼1 Prðg
2it
Þ¼F½d
it
; r
it
; e
it
ð1Þ
where i ¼ individual and t ¼ time. The function F[y] denotes the function
e
y
/(1 + e
y
). The variables d and r, as described in equations 2 and 3 indicate the
process of minimizing future disappointment and future regret, respectively;
e indicates the result of maximizing expected values.
d ¼ðjy
2
x
2
jð1 qÞÞ ðjy
1
x
1
jð1 pÞÞ ð2Þ
r ¼jy
2
x
1
jjy
1
x
2
jð3Þ
e ¼ EVðg
1
ÞEVðg
2
Þ¼ðpx
1
+ð1 pÞy
1
Þðqx
2
+ð1 qÞy
2
Þð4Þ
Subjects would choose g
1
, minimizing disappointment (equation 2), if the
difference in absolute value between the lowest and the highest possible
outcome in g
2
, weighted by the probability of the lowest outcome, were larger
than the same weighted difference in g
1
. The process of anticipating regret is
described by the minimization of the difference between the lowest and the
highest outcome across gambles (equation 3). Finally, subjects would choose g
1
if its expected value (EV) is higher than that of g
2
(equation 4). A restricted
version of the model, where we considered only the effect of anticipated
disappointment (d) and maximization of expected values (e), was tested with
the data from the ‘partial choose’ condition (Table 2a).
Functional imaging data: acquisition, pre-processing and analysis. Subjects
were scanned at 3 T (Siemens Allegra) performing the experimental task over
two counterbalanced sessions. T2-weighted echoplanar images, optimized for
blood oxygenation level–dependent (BOLD) contrast, were acquired (TE:
30 ms, TR
vol
:2.86s,44slicesangledat301 in anterior-posterior axis). A
preparation pulse (duration 1 ms, amplitude 2 mT/m) was used in the slice
selection direction to compensate for through-plane susceptibility gradients for
enhancement of imaging of orbitofrontal and medial temporal lobe regions
46
.
The efficient imaging of these regions (cross-hairs) is illustrated in Supple-
mentary Figure 3, depicting smoothed normalized EPI images and corre-
sponding locations in a normalized structural template image.
Image pre-processing and subsequent analyses were done using statistical
parametric mapping (SPM2; http://www.fil.ion.ucl.uk/~spm/SPM2.html) on a
Matlab platform. Images were initially realigned and unwarped, correcting for
motion artifacts. Differences in the timing of image slices across each individual
volume were corrected, and each volume was transformed into standard
stereotaxic space and smoothed with a Gaussian filter (full-width half-max-
imum 8 mm). Voxel-wide differences in BOLD contrast within the smoothed
normalized images resulting from the different task conditions and trial types
were examined using SPM. Standard neuroimaging methods using the
general linear model were used with the first level (individual subject
analyses) providing contrasts for group effects analyzed at the second level.
All individual analyses modeled the period of stimulus presentation
up to choice selection as a mini-epoch. Activity at outcome was likewise
modeled as a mini-epoch, segregating complete and partial feedback trials
for ‘choose’ and ‘follow’ conditions. In the fMRI data analysis, the outcomes
of each trial were modeled as 3-s epochs beginning at 1 s before the
outcome display stopped (that is, when the spinning arrow began to slow,
enabling prediction of its end point) and continuing for a further 2 s
while the trial outcome was displayed (and processed). Choice-related neural
activity at the time of choice was studied during the epoch between trial onset
and subject response. To model the hemodynamic lag of the BOLD response
relative to underlying evoked neural activity, regressors for task effects were
obtained by convolving these mini-epochs with a canonical hemodynamic
response function.
We did not jitter timings within trials to discriminate overlapping ‘raw’
evoked hemodynamic BOLD responses related to the choice and outcome
phases (although some temporal variability arose from the time it took the
subject to select between gambles on ‘choose’ conditions). Thus, the temporal
proximity (and lack of jittering) between the decision-making and outcome
components of each trial resulted in overlapping of BOLD responses between
these different phases. However, our principal analyses focused on modulation
of outcome-related activity by parameters not embodied within the decision or
anticipation phases (regret, disappointment, win/loss). Furthermore, contrasts
(Student’s t-tests) within our regression analyses identify activity that is not
otherwise accountable for in the analytic design. Thus, the impact of shared
variance in activity between choice and parametric modulators of outcome is
minimized or excluded in results from first- and second-level analyses by virtue
of this orthogonalization with analyses modeling decision and outcome epochs
independently of their parametric modulation.
Three sets of analyses were performed. In the first, outcome trials were
partitioned according to whether the subject experienced a loss or a win and
additional regressors parametrically modeling the degree of disappointment
and, for complete-feedback trials, regret experienced at the time of outcome. In
two further analyses, activity for win and loss trials were not modeled
separately, and parametrical regressors of activity at choice modeled experience
of regret on the preceding trial and mean regret experienced over the course of
the task prior to the choice, respectively. For group analysis of outcome-related
activity, second-level analyses of contrast for regret and disappointment for
different trial types were computed as ANOVAs with sphericity correction for
repeated measures. Post-hoc exploration of individual data is also reported to
illustrate specific effects as a function of different trial types. For choice-related
activity, contrasts relating to prior experience of regret were modeled for
complete and partial trials in a second-level ANOVA, taking into account group
effects of prior regret experienced. Adjusted activity represents BOLD signal
changes proportionally adjusted for the analytic model. Although general
threshold significance was set at P o 0.05, corrected, we tabulate group effects
at P o 0.001, uncorrected, to highlight regions of interest. For illustrative
purposes, we show Figure 5b at P o 0.005, uncorrected.
Modeling cumulative regret. The regressor to test activity at choice that
reflected cumulative regret (Fig. 5b and Ta bl e 3c) represented the difference
between missed payoff and payoff realized from past choice in the complete
feedback condition (‘complete choose’ condition (CC)) over time, that is,
CR
t
¼ (A
unobtained, t – 1
– A
obtained, t – 1
), where CR is cumulative regret, t is trial,
A
obtained
is the average payoff realized and A
unobtained
is the average payoff of the
unselected gambles.
Note: Supplementary information is available on the Nature Neuroscience website.
ACKNOWLEDGMENTS
This work was supported by grants from the Human Frontier Science Program
(RGP 56/2005), the Action Concerte
´
e Incitative, Systemes Complexes from the
Centre National de la Recherche Scientifique to A.S. and G.C., the Coordenac¸a
˜
o
NATURE NEUROSCIENCE VOLUM E 8
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SEPTEMBER 2005 1261
ARTICLES
© 2005 Nature Publishing Group http://www.nature.com/natureneuroscience
de Aperfeic¸oamento de Pessoal de Nı
´
vel Superior to M.J., a Wellcome Trust
Programme Grant to R.J.D. and a Wellcome Senior Fellowship in Clinical Science
to H.D.C.
COMPETING INTERESTS STATEMENT
The authors declare that they have no competing financial interests.
Received 29 April; accepted 11 July 2005
Published online at http://www.nature.com/natureneuroscience/
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