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Fear fosters flight: A mechanism for fear contagion
when perceiving emotion expressed by a whole body
Beatrice de Gelder*
†‡
, Josh Snyder*, Doug Greve*, George Gerard*, and Nouchine Hadjikhani*
*Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, First Street Building 36, Charlestown, MA 02129; and
†
Cognitive and Affective Neurosciences Laboratory, Tilburg University, P.O. Box 90153, 5000 LE, Tilburg, The Netherlands
Communicated by Richard M. Held, Massachusetts Institute of Technology, Cambridge, MA, September 27, 2004 (received for review May 16, 2004)
Darwin regarded emotions as predispositions to act adaptively,
thereby suggesting that characteristic body movements are asso-
ciated with each emotional state. To this date, investigations of
emotional cognition have predominantly concentrated on pro-
cesses associated with viewing facial expressions. However, ex-
pressive body movements may be just as important for under-
standing the neurobiology of emotional behavior. Here, we used
functional MRI to clarify how the brain recognizes happiness or
fear expressed by a whole body. Our results indicate that observ-
ing fearful body expressions produces increased activity in brain
areas narrowly associated with emotional processes and that this
emotion-related activity occurs together with activation of areas
linked with representation of action and movement. The mecha-
nism of fear contagion hereby suggested may automatically pre-
pare the brain for action.
emotion communication 兩 body movement 兩 action 兩 social cognition 兩
amygdala
W
hen danger lurks, fear spreads through a crowd as body
postures alter in rapid cascade from one individual to the
next. A nimal ethologists have described situations in which
emotions are c ommunicated behav iorally through rapidly chang-
ing behavior as can be observed in the flight of a flock of birds
when a source of danger appears at the horizon (1). The notion
of emotional contagion is sometimes used to refer to similar
automatic posture adjustments in humans (2). From Darwin’s
evolutionary perspective, commun ication of emotion by body
movements occupies a privileged position as emotions embody
action schemes that have evolved in the service of survival (3).
However, at present, little is known about the possible mecha-
n isms in the human brain sustaining bodily communication of
emotion in the service of adaptive action. The present study
begins to explores this issue.
To date, most investigations of the perception of emotion have
c oncentrated on brain activity generated by the recognition of
still images of facial expressions, and virtually all that is known
about perception of emotion in humans is based on such data.
Major insights concern the role of the amygdala in c oncert with
that of the fusiform c ortex, prefontal c ortex, orbitofrontal cortex
(OFC), medial f rontal cortex, superior temporal sulcus, and
somatosensory cortex (4, 5). Interestingly, however, some of
these same areas also seem to play a role in processing biological
movement. For example, viewing biological movement patterns,
which are experienced as pleasant, activates subcortical str uc-
tures, including the amygdala (6), and visual perception of
biological motion activates two areas in the occipit al and fusi-
for m cortex (7). Recent findings in non-human primates have
drawn attention to the brain’s abilit y to represent actions through
canon ical neurons (similarly active when viewing an object and
grasping it) and mirror neurons (similarly active when observing
an action and performing the action) (8, 9). However, to date,
it is not known whether these brain areas play a role when
humans view body movements expressing emotion.
Studies on neutral body postures and movements have already
revealed some intriguing similarities between visual perception
of faces and of bodies. For example, faces and bodies both have
c onfigural properties as indexed by the inversion effect (10), and
the global structure of the whole body is also an important factor
in the perception of biological motion (11). Evidence from
single-cell recordings suggests a degree of specialization for
either face or body images (9). Neurons reacting selectively to
body posture have been found in rec ordings from monkey
superior temporal sulcus. Similarly, a functional MR I study
ex ploring the contrast between objects and neutral body postures
revealed activity in lateral occipitotemporal c ortex (12). On the
other hand, there appear to be similarities between emotional
body expressions and faces. A striking finding (13) is that
observing bodily expressions activates two well k nown face areas
(inferior oc cipital gyr us and middle fusifor m gyrus) predomi-
nantly associated w ith processing faces but also linked with
biological movement (6). These activations in face-related areas
may result from mental imagery (14), or alternatively, and more
probably, from c ontext driven high-level perceptual mechanisms
filling in the face information missing in the input. However, this
is unlikely to be the only explanation for similarities between
facial and bodily expressions of fear. In a direct comparison of
facial expressions and bodily expressions, we obser ved that the
N170 waveform is obtained for faces and bodies alike, but not for
objects (15). The time window of the N170 waveform suggests
that there is similarity in visual encoding bet ween faces and
bodies. A further indication is provided by the fact that fusiform
gyrus activity is specifically related to present ation of fearful
bodily expressions. This finding suggests a mechanism whereby
amygdala modulates activation in visual areas, including fusi-
for m face cortex as previously found for facial expressions
(16, 17).
The present study investigated the perception of fear ful and
happy bodily expressions by using functional MRI. We used a
t wo-condition paradigm, in which images of bodily ex pressions
of fear and happiness alternated with images of meaningful but
emotionally neutral body movements. These whole-body actions
provide an appropriate control condition because, similar to
emotional body movements, they cont ain biological movement,
they have semantic properties (unlike abstract movement pat-
terns), and they are familiar. Selecting meaningful neutral body
movements allowed us to create comparable conditions with
respect to implicit movement perception, which is a process we
ex pected to take place when participants viewed still images of
body actions. To focus specifically on whole-body expressions, in
all images the faces were blanked out. To avoid task interference,
we used a passive viewing situation and participants were not
given instructions that might have prompted imitation or ment al
imagery of the actions shown. Our main hypothesis was that
viewing bodily expressions of emotions (either fear or happiness)
would specifically activate areas known to be involved in pro-
Freely available online through the PNAS open access option.
Abbreviations: OFC, orbitofrontal cortex; SMA, supplementary motor area; IFG, inferior
frontal gyrus.
‡
To whom correspondence should be addressed. E-mail: degelder@nmr.mgh.harvard.edu.
© 2004 by The National Academy of Sciences of the USA
www.pnas.org兾cgi兾doi兾10.1073兾pnas.0407042101 PNAS
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PSYCHOLOGY
cessing emotional signals, as well as areas dedicated to action
representation and motor areas.
Methods
Participants. Functional magnetic resonance images of brain
activit y of seven participants (four males) were collected in a 3-T
high-speed echoplanar imaging device (Siemens, Erlangen, Ger-
many) by using a quadrature head coil. Infor med written consent
was obtained for each participant before the scanning session,
and the Massachusetts General Hospital Human Studies Com-
mittee approved all procedures under Protocol no. 2002P-
000228. Image volumes consisted of 45 contiguous 3-mm-thick
slices covering the entire brain (repetition time of 3,000 ms,
3.125 ⫻ 3.125 mm in-plane resolution, 128 images per slice; echo
time of 30 ms, flip angle of 90°; 20 ⫻ 20 cm field of view, 64 ⫻
64 matrix).
Materials. Video recordings of 16 semiprofessional actors (eight
women, 22–35 years of age) were used for stimulus c onstruction.
Actors performed with their whole body meaningful but emo-
tionally neutral actions (pouring water into a glass, c ombing
one’s hair, putting on trousers, or opening a door) or expressive
gestures (happy, fearful, sad, or angry). In each case, before the
rec ordings they were briefed with a set of standardized instruc-
tions. For the neutral body actions, instr uctions specified the
action to be performed. For emotional body actions, instructions
specified a familiar scenario (for example, opening a door and
finding an armed robber in front of you). Still images were
obt ained f rom the videos by selecting manually the most infor-
mative frames from the video file and converting them to
grayscale pictures. Four-choice identification tests were admin-
istered to a group of participants (n ⫽ 18, nine women, 22–35
years of age), one with 64 pictures of the ex pressive gestures (16
actors ⫻ 4 emotions) and one with 64 pictures of emotionally
neutral gestures (16 actors ⫻ 4 t ypes of gestures). Average
identification ac curacy was 75% for emotional and 94% for
neutral gestures. On the basis of these results, the eight best-
rec ognized images of happy and fearful gestures were retained
f rom the emotion category for subsequent testing. For the
neutral gestures, the eight best-recognized picture were equally
ret ained. Mean percent correct four-choice identification for the
ret ained pictures was 85% for the emotional and 95% for the
neutral gestures.
A second pilot experiment was run with a different group of
subjects (n ⫽ 10, six women, 24–33 years of age) to obtain data
on intensity of evoked movement impression. The 24 images
ret ained for the main experiment were presented one by one in
random order and subjects were instructed to rate the movement
infor mation on a five-point scale (from 1 for the weakest
impression to 5 for the strongest). The mean ratings for the three
categories were nearly identical (neutral, 3.5; fearful 3.5; and
happy, 3.3). The possibility that the obtained differences in
activation level were artifacts of differences in evoked movement
can safely be discarded.
In the scanner, the 24 selected images (8 fearful, 8 happy, and
8 neutral) were used in two separate r uns by using an AB-
blocked design (fearful vs. neutral; happy vs. neutral). Each
block lasted 24 s, during which the pictures were randomly
presented for 300 ms followed for 1,700 ms by a blank interval
during which only a fixation cross was present.
Data Analysis. The techniques used in our analysis are similar to
those described in ref. 18. Each functional run was first motion-
c orrected with
AFN I sof tware (19) and spatially smoothed by
using a three-dimensional Gaussian filter with full width at half
maximum of 6 mm. The mean offset and linear drift were
estimated and removed from each voxel. The spectrum of the
remain ing signal was c omputed by using the fast Fourier trans-
for m at each voxel. The task-related component was estimated
as the spectral component at the task fundament al f requency.
The noise was estimated by summing the remaining spectral
c omponents after removing the task harmonics and those com-
ponents immediately adjacent to the fundament al. The phase at
the fundamental was used to deter mine whether the blood
oxygenation level-dependent (BOLD) signal was increasing in
response to the first stimulus (positive phase) or the second
stimulus (negative phase).
Each participant’s functional MRI scan was registered to a
high-resolution T1. The real and imaginary components of the
Fourier transfor m of each participant’s signal were resampled
f rom locations in the c ortex onto the sur face of a template sphere
to bring them into a standard space. The techniques for mapping
bet ween an individual volume and this spherical space are
det ailed by Fischl et al . (20). The T1 volume was also registered
to the MNI305 Talairach brain (21). Functional data were
registered to the T1 volume. This procedure allowed the results
of the individual per-voxel analysis to be resampled into both
volume-based Talairach space and the sur face-based spherical
space to perform group random effects analysis. Group-average
sign ificance maps for the cortical surface and for the volume
were computed, by using General Linear Model analyses to
perform random-effects averages of the real and imaginary
c omponents of the signal across subjects on a per-vertex and
per-voxel basis. Cross-subject variance was computed as the
variance pooled across the real and imaginary c omponents.
Sign ificance of the average activation was deter mined by using
an F st atistic and mapped from the standard sphere to a target
individual’s cortical surface (20). Maps were visualized on this
individual’s surface geometry, overlaying a group curvature
pattern averaged in spherically morphed space (20, 22).
On the cortical surfaces, clusters of contiguous vertices with a
sign ificance of P ⬍ 0.05 and covering an area of at least 185 mm
3
were identified. Talairach coordinates and the c orresponding
str ucture of the center of each cluster, identified by visual
inspection of the target individual’s anatomy, are given in Table
1. To c orrect these clusters for multiple comparisons, 5,000
Monte Carlo simulations of the averaging and clustering proce-
dure were r un, by using as input volumes synthesized white
Gaussian noise, smoothed and resampled into spherical space.
Clusters were found in 187 cases, yielding a significance of P ⫽
0.0374 for the clusters. We similarly identified clusters in the
Talairach space average, by using P ⬍ 0.05 and volume of ⬎135
mm
3
as constraints.
Results
Observed activities for the fear vs. neutral comparison were
grouped in functionally related clusters: areas related to emo-
tional stimulus detection and orientation, areas related to visual
processing, areas associated with emotional evaluation, areas
associated with action representation, and motor response areas
(Figs. 1–4 and Table 1).
Discussion
Our major finding is that v iewing fearful whole-body ex pressions
produces higher activ ity in areas specifically known to process
emotional information (amygdala, orbitofront al cortex, poste-
rior cingulate, anterior insula, retrospenial cortex, and nucleus
ac cumbens) than viewing images of meaningful but emotionally
neutral body actions. In contrast, a similar c omparison of happy
bodily expressions with neutral ones only yielded increased
activit y in visual areas. Besides activity in emotion-related areas,
we also observed significant fear-related activation in areas
dedicated to action representation and in motor areas. The
integrated activity of these groups of areas may constitute a
mechan ism for fear contagion and for preparation of action in
response to seeing fear, which presumably operates in a direct,
16702
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www.pnas.org兾cgi兾doi兾10.1073兾pnas.0407042101 de Gelder et al.
automatic, and noninferential fashion, similar to what has so far
been argued for automatic rec ognition of fear in facial expres-
sions (4, 23).
Observing fearful body expressions modulates cortical and
subc ortical visual areas. Previous studies (24) have shown that
the emotional component of a stimulus is reflected in higher
activation in visual cortices as we find here for both the contrast
bet ween fear vs. neutral and happy vs. neutral body represen-
t ations. The activity related to stimulus detection兾orientation
and v isual processes in superior colliculus and pulvinar is
c ompatible with models in which a rapid automatic route for fear
detection is envisaged (5, 25, 26). A major function of this route
is to sustain rapid orientation and detection of potentially
dangerous signals based on coarse visual analysis, as can be
performed by the superior colliculus. This subcortical motor
activit y may be part of a broader subcortical pathway for
processing fear signals and involving projection from retina to
superior colliculus and to pulvinar, as previously argued for faces
(26–28). The pathway allows processing within a limited range of
spatial frequencies that is still sufficient for facial expressions as
illustrated by residual visual abilities of patients with striate
c ortex lesions (28). This same nonstriate subcortical-based route
can also sustain recogn ition of bodily ex pression of emotion in
patients with striate cortex damage (B.d.G., L. Weiskrantz, and
N.H., unpublished data).
Our results indicate that viewing bodily expression of emotion
influences activit y in visual cortical areas that have shown
modulation of activity as a function of emotional valence of the
stimuli (striate and extrastriate cortex, fusiform gyrus, inferior
oc cipital gyr us, and middle occipital cortex) (16, 17, 29). In
c ontrast, in the happy vs. neutral condition, the only areas that
were sign ificantly more activated for the happy condition were
located in the left and the right visual cortices (see Table 2).
Emotional modulation of visual processes has so far only been
observed when facial expressions were used as stimuli.
The present finding of amygdala activation for fear expressed
in the whole body contrasts with neuropsychological reports
suggesting that amygdala damage only impairs emotion recog-
Table 1. Areas of activation observed in the comparison of
fearful bodily expressions with neutral ones
Areas of activation Side xy z
Detection and orientation
Superior colliculus L ⫺5 ⫺31 ⫺2
R4⫺31 ⫺3
Pulvinar L ⫺7 ⫺25 5
R6⫺25 7
Visual areas
Striate cortex L ⫺8 ⫺82 5
L ⫺20 ⫺100 8
R14⫺100 10
Fusiform gyrus L ⫺32 ⫺51 ⫺14
R35⫺60 ⫺12
Inferior occipital gyrus L ⫺9 ⫺68 40
Precuneus R 43 ⫺78 ⫺7
Emotional evaluation
OFC R 38 30 ⫺12
Posterior cingulate cortex L ⫺8 ⫺49 27
Anterior insula L ⫺31 10 10
R3116⫺4
Retrosplenial cortex R 13 ⫺45 0
Nucleus accumbens L ⫺510⫺6
R410⫺3
Amygdala R 24 0 ⫺16
Action representation兾premotor areas
IFG, BA 44 L ⫺43 14 10
R441723
IFG, BA 45 L ⫺51 25 1
R4328⫺2
IFG, BA 47 L ⫺42 22 ⫺9
Precentral gyrus, BA 6 L ⫺44 12 36
R50 30
R45 238
SMA L ⫺5 ⫺159
R 8 10 45
R11⫺766
Inferior parietal lobule L ⫺39 ⫺55 50
Intraparietal sulcus, posterior part R 27 ⫺83 21
Motor areas
Precentral gyrus, BA 4 L ⫺33 ⫺654
L ⫺44 ⫺344
R54⫺335
Caudate nucleus R 15 6 15
L ⫺10 3 13
Putamen R 24 1 9
L ⫺25 ⫺15
Other areas
Parahippocampal gyrus L ⫺13 ⫺41 ⫺3
R24⫺31 ⫺8
Subheadings represent presumptive functional groupings. All clusters re-
ported here are ⬍0.05 corrected and have a minimal size of 128 mm
2
(see
Methods). L, left; R, right; BA, Brodmann’s area.
Fig. 1. Areas of activation corresponding to viewing body expression of fear
vs. neutrality are represented on the cortical surface. Data were obtained by
random-groups average of the subjects and are corrected for multiple com-
parisons (see Table 1). L, left; R, right.
Fig. 2. Activity in subcortical structures. Random-group average of fearful
vs. neutral body images. Data are rendered on one template brain, in a
common Talaraich space (radiological conventions). Data presented are at a
threshold of P ⬍ 0.01 uncorrected. Areas are color-coded according to the Fig.
3 legend.
de Gelder et al. PNAS
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November 23, 2004
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PSYCHOLOGY
n ition for faces, but not for scenes in which facial ex pressions
were erased and has led to the notion that amygdala might be
specialized only for facial expression of fear (30). The present
results clearly indicate otherwise. As our design maximized
similarit y bet ween conditions for all stimulus aspects, except
those related to emotion, we did not predict condition-specific
activit y in visual areas associated with viewing human bodies in
lateral occipitotemporal cortex (12). Our results raise the pos-
sibilit y that the similarity in neural activity for the perception of
bodily expressions and facial expressions may be due to synergies
bet ween the mechanisms underlying recognition of facial ex-
pressions and body expressions, and to common str uctures
involved on the one hand in action representation, and on the
other in rapid detection of salient information like a fearful
bodily expressions.
Of special interest, given the use of body images, is the activity
in OFC, which influences response to stimuli at multiple levels
of processing (31). Signals arising in OFC control regulatory
processes in emotions and feelings in the body but also in the
brain’s representation of the body (32). OFC acts in concert with
the amygdala and somatosensory兾insular cortices, both activated
here. Observed activ ity in anterior insula is consistent with the
role of this structure in connecting prefrontal cortex and the
limbic system and w ith the role of insula in interoception (33).
Activit y in posterior cingulate cortex is consistent with earlier
findings of a role for this structure in studies of emotional
salience (34). Interestingly, besides their role in emotional
processes, posterior cingulate and retrosplenial cortex are asso-
ciated w ith spatial coding (35). Also of interest is the finding that
nucleus acccumbens figures among the emotion-specific activa-
tions, indicating that this structure plays a role not only in reward
(36) but also, more generally, in processing affective stimuli,
including negative ones.
A n important area of research in the last decade concerns the
way in which the brain recogn izes actions. In studies of non-
human primates, both canonical and mirror neurons have been
observed (8, 9, 37). Findings f rom cell recordings in monkeys, as
well as from neuroimaging studies in humans (9, 38–40), provide
increasing insight for a network of structures dedicated to action
representation. The superior temporal sulcus, the parietal cor-
tex, and the premotor cortex are activated during the perception
of simple finger movements (41), pantomimes (42–44), and
object-directed actions (9, 43–45). Areas that are reported to be
active under conditions of imit ation and imagined action or
motor imagery are the dorsolateral prefrontal cortex, precentral
gyrus, supplementary motor area (SMA), inferior pariet al lobe,
cingulate, subcortical nuclei, and cerebellum (44). Now, our
results indicate that viewing images of bodily expressions of fear
activates central str uctures in the net work of areas previously
associated w ith the observation of action (44): the premotor
c ortex, SMA, inferior frontal gyrus (IFG), middle f rontal gyrus,
and parietal cortex. In the present case, the activations are not
ex plained by the presence of object-directed movements or even
of movement per se. Passive viewing of still images of bodily
ex pressions activates areas in the occipitoparietal pathway reach-
ing the SMA, cingulate gyrus, and middle frontal gyrus, which
has been detected during the observation of actions with the
intent to imitate later and voluntary action (42, 44), and suggests
that passive viewing can initiate motor preparation. Activit y in
caudate nucleus was also observed for motion stimuli (46).
Interestingly, the present activations may follow from a process
Fig. 3. Schematic representation of areas activated in the processing of
bodily expression of fear. Areas of activation selective for viewing fearful
expressive bodies are represented in presumptive functional groupings. Five
different functional functionally grouped areas are activated: areas involved
in stimulus detection and orientation (yellow), visual processing (purple),
emotional processing (red), action representation (orange), and motor re-
sponse (green). Arrows indicate interactions between these different groups
of areas.
Fig. 4. Examples of stimuli used in this experiment. (a) Fearful. (b) Neutral.
(c) Happy.
Table 2. Areas of activation observed in the comparison of
happy bodily expressions with neutral ones
Area of activation Side xyz
Visual areas
Striate cortex Left ⫺10 ⫺95 20
Left ⫺13 ⫺84 ⫺2
Right 13 ⫺98 18
Right 11 ⫺86 3
All clusters reported here are ⬍ 0.05 corrected and have a minimal size of
128 mm
2
(see Methods).
16704
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www.pnas.org兾cgi兾doi兾10.1073兾pnas.0407042101 de Gelder et al.
whereby the brain fills in the missing dynamic information (47).
Yet, the important point here is that this process is specific for
fear, as indicated by the fact that the fear images produce
increased activation in well known emotional areas. It is also
unlikely that the activity in these emotion-related areas would be
produced by the presence of more implicit motion cues in the
fear than in the neutral body images. As indicated by the results
of the sec ond pilot experiment, there is no difference between
the images in this respect. So far, activation of emotion-related
brain areas for movement per se has not been reported in the
literature. In the happy-neutral blocks, the only activity related
to the emotion as compared with the neutral condition c oncerns
visual areas. This finding suggests that seeing happy bodily
ex pressions evokes considerably less condition-specific activity
in areas related to action representation and in motor areas.
Presumably, action representation and motor imagery are also
present in the happy-neutral condition without being specific for
perceiving either happy or neutral bodily expressions.
Of particular interest is the activity in SMA. Our central
prediction was that v iewing bodily expressions would activate
areas related to processing emotion and generate activity in
motor areas through cingulate and prefrontal areas with a cr ucial
role to be played by SM A, given the connections of SMA to M1.
Activit y in the pre-SMA face area is consistent with previous
reports (43, 48) on its role in preparation to act more than in
action observation. In this case, pre-SMA activity may reflect
preparation to act upon perceiv ing fear in others. SMA itself may
also play a role in movement control in case of emotion-inducing
stimuli. The present results are consistent with findings on
reciprocal interactions bet ween the amygdala and subcortical
and c ortical str uctures involving the striatum and OFC (49). The
present finding of the role of body represent ations in emotional
st ates evokes the findings on spontaneous and automatic imita-
tion of facial expression observed earlier (50). As been argued
in the latter case, such imitative reflexes are nonintentional and
cannot be observed with the eye but they stand out clearly in
electromyography measurements. At the conceptual level, such
emotional resonance or cont agion effects may correspond to
minor functional changes in the threshold of bodily st ates in the
service of automatic action preparation. Processes responsible
for contextual integration with real-world knowledge presum-
ably regulate and suppress these emotional body reflexes when
they are not adaptive.
Whole-body expressions of emotion have not been used
previously to study emotional processes in the brain. Our
findings are consistent with the notion that the amygdala is a
critical substrate in the neural system necessary for triggering
somatic states from primary inducers (51), among which the
sight of a fearful body expression figures. The observed coupling
of the strong emotion-related activity with structures involved in
canon ical action represent ation (predominantly the parietomo-
tor circuit) and the mirror neurons circuit (predominantly the
intrapariet al sulcus, dorsal premotor cortex, superior temporal
sulcus, and right parietal operculum) suggests that the two
str uctures play a role in social communication (52). Further
research is needed to clarify these issues. Finally, the present
results indicate a role of the putamen and caudate nucleus in
viewing bodily expressions of fear. Interestingly, the caudate
nucleus and putamen are predominantly known for their in-
volvement in motor tasks but have also been associated with
motivational-emotional task components. The caudate nucleus
and putamen are damaged in Parkinson’s disease (53) and
Huntington’s disease (54), which are both characterized by
motor disorders as well as by emotion deficits.
Our study shows that present ation of stimuli expressing fear
produces, besides activation of centers associated with emotion,
activations of circuits mediating actions. This finding clearly
suggests an intrinsic link between emotion and action. Yet, it
does not imply that neutral stimuli or stimuli expressing happi-
ness do not activate these circuits, which we know they do (55).
As a matter of fact, we capitalized on the findings that still images
of neutral actions elicit action representation and are thus
appropriate to use as controls for investigating emotional body
ex pressions, which, as we predicted, also elicit action represen-
t ation.
A central issue to consider in future research c oncerns the
relation between emotion and movement. However, at present,
we do not know whether the dynamics and kinematics of fearful
body movements are quantitatively and qualitatively different
f rom those of neutral actions and from movements expressing
emotions other than fear. For example, it is not yet k nown
whether actions and body expressions of emotions are all built
f rom the same basic set of motor primitives. In that perspective,
the movement properties of emotional body expressions are best
seen as modulations of a basic set of all-purpose motor primi-
tives, or a general motor syntax. Alternatively, emotional body
ex pressions represent a domain of sui generis motor compe-
tence.
We thank M. Balsters for assist ance with preparation of the materials.
This work was supported by a grant from Tilburg Universit y and National
Institutes of Health Grant RO1 NS44824-01 (to N.H.).
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