Sorry the PET scans didn't come through
but this is easily found on the web.
Where'd you git 'cher spell checka? It
tells me that there are precisely 100
misspelled words in the following article.
I'm sure it will up the total after this edit.
Neural activation to facial and vocal
emotion
Neuropsychological findings of selective
deficits of emotion recognition (see
Neuropsychological case studies) have
led to functional imaging studies of
responses to signals of emotion in the
neurologically normal brain.
Further studies are being conducted in
collaboration with Mary Phillips and
Jeffrey Gray.
Right: Image from Philips et al. (1997).
The difference image demonstrating
significant (P < 0004) differences in
activation for perception of faces depicting
150% intensity of disgust (versus a
neutral expression) and faces depicting
75% intensity of disgust (versus a neutral
expression). The largest region of
activation was in the right anterior insula
(Talairach coordinates 38, 17, 9), with
twice the number of activated voxels
compared with other regions of the
difference image. Transverse (z = 9) and
coronal (y = 17) sections are shown
depicting this activation in the right insula.
Published work on this topic includes:
Morris, J.S., Frith, C.D., Perrett, D.I.,
Rowland, D., Young, A.W., Calder, A.J.
and Dolan, R.J. (1996). A differential
neural response in the human amygdala
to fearful and happy facial expressions.
Nature, 383, 812-815.
Morris, J.S., Friston, K.J., Büchel, C., Frith,
C.D., Young, A.W., Calder, A.J. and Dolan,
R.J. (1998). A neuromodulatory role for
the human amygdala in processing
emotional facial expressions. Brain, 121,
47-57.
Phillips, M.L., Young, A.W., Senior, C.,
Brammer, M., Andrew, C., Calder, A.J.,
Bullmore, E.T., Perrett, D.I., Rowland, D.,
Williams, S.C.R., Gray, J.A. and David,
A.S. (1997). A specific neural substrate for
perceiving facial expressions of disgust.
Nature, 389, 495-498.
Phillips, M.L., Young, A.W., Scott, S.K.,
Calder, A.J., Andrew, C., Giampetro, V.,
Williams, S.C.R., Bullmore, E.T.,
Brammer, M. and Gray, J.A. (1998).
Neural responses to facial and vocal
expressions of fear and disgust.
Proceedings of the Royal Society:
Biological Sciences, B265, 1809-1817.
Abstracts:
Morris, J.S., Frith, C.D., Perrett, D.I.,
Rowland, D., Young, A.W., Calder, A.J.
and Dolan, R.J. (1996). A differential
neural response in the human amygdala
to fearful and happy facial expressions.
Nature, 383, 812-815.
The amygdala is thought to play a crucial
role in emotional and social behaviour.
Animal studies implicate the amygdala in
both fear conditioning and face
perception. In humans, lesions of the
amygdala can lead to selective deficits in
the recognition of fearful facial
expressions and impaired fear
conditioning, and direct electrical
stimulation evokes fearful emotional
responses. Here we report direct in vivo
evidence of a differential neural response
in the human amygdala to facial
expressions of fear and happiness.
Positron-emission tomography (PET)
measures of neural activity were acquired
while subjects viewed photographs of
fearful or happy faces, varying
systematically in emotional intensity. The
neuronal response in the left amygdala
was significantly greater to fearful as
opposed to happy expressions.
Furthermore, this response showed a
significant interaction with the intensity of
emotion (increasing with increasing
fearfulness, decreasing with increasing
happiness). The findings provide direct
evidence that the human amygdala is
engaged in processing the emotional
salience of faces, with a specificity of
response to fearful facial expressions.
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Morris, J.S., Friston, K.J., Büchel, C., Frith,
C.D., Young, A.W., Calder, A.J. and Dolan,
R.J. (1998). A neuromodulatory role for
the human amygdala in processing
emotional facial expressions. Brain, 121,
47-57.
Localized amygdalar lesions in humans
produce deficits in the recognition of
fearful facial expressions. We used
functional neuroimaging to test two
hypotheses: (i) that the amygdala and
some of its functionally connected
structures mediate specific neural
responses to fearful expressions; (ii) that
the early visual processing of emotional
faces can be influenced by amygdalar
activity. Normal subjects were scanned
using PET while they performed a gender
discrimination task involving static
grey-scale images of faces expressing
varying degrees of fear or happiness. In
support of the first hypothesis, enhanced
activity in the left amygdala, left pulvinar,
left anterior insula and bilateral anterior
cingulate gyri was observed during the
processing of fearful faces. Evidence
consistent with the second hypothesis
was obtained by a demonstration that
amygdalar responses predict
expression-specific neural activity in
extrastriate cortex.
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Phillips, M.L., Young, A.W., Senior, C.,
Brammer, M., Andrew, C., Calder, A.J.,
Bullmore, E.T., Perrett, D.I., Rowland, D.,
Williams, S.C.R., Gray, J.A. and David,
A.S. (1997). A specific neural substrate for
perceiving facial expressions of disgust.
Nature, 389, 495-498.
Recognition of facial expressions is
critical to our appreciation of the social
and physical environment, with separate
emotions having distinct facial
expressions. Perception of fearful facial
expressions has been extensively
studied, appearing to depend upon the
amygdala. Disgust-literally 'bad taste'-is
another important emotion, with a distinct
evolutionary history, and is conveyed by a
characteristic facial expression. We have
used functional magnetic resonance
imaging (fMRI) to examine the neural
substrate for perceiving disgust
expressions. Normal volunteers were
presented with faces showing mild or
strong disgust or fear. Cerebral activation
in response to these stimuli was
contrasted with that for neutral faces.
Results for fear generally confirmed
previous positron emission tomography
findings of amygdala involvement. Both
strong and mild expressions of disgust
activated anterior insular cortex but not
the amygdala; strong disgust also
activated structures linked to a limbic
cortico-striatal-thalamic circuit. The
anterior insula is known to be involved in
responses to offensive tastes. The neural
response to facial expressions of disgust
in others is thus closely related to
appraisal of distasteful stimuli.
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Phillips, M.L., Young, A.W., Scott, S.K.,
Calder, A.J., Andrew, C., Giampetro, V.,
Williams, S.C.R., Bullmore, E.T.,
Brammer, M. and Gray, J.A. (1998).
Neural responses to facial and vocal
expressions of fear and disgust.
Proceedings of the Royal Society:
Biological Sciences, B265, 1809-1817.
Neuropsychological studies report more
impaired responses to facial expressions
of fear than disgust in people with
amygdala lesions, and vice versa in
people with Huntington's disease.
Experiments using functional magnetic
resonance imaging (fMRI) have
confirmed the role of the amygdala in the
response to fearful faces and have
implicated the anterior insula in the
response to facial expressions of
disgust. We used fMRI to extend these
studies to the perception of fear and
disgust from both facial and vocal
expressions. Consistent with
neuropsychological findings, both types
of fearful stimuli activated the amygdala.
Facial expressions of disgust activated
the anterior insula and the
caudate-putamen; vocal expressions of
disgust did not significantly activate either
of these regions. All four types of stimuli
activated the superior temporal gyrus. Our
findings therefore (i) support the
differential localization of the neural
substrates of fear and disgust; (ii) confirm
the involvement of the amygdala in the
emotion of fear, whether evoked by facial
or vocal expressions; (iii) confirm the
involvement of the anterior insula and the
striatum in reactions to facial expressions
of disgust; and (iv) suggest a possible
general role for the perception of
emotional expressions for the superior
temporal gyrus.
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