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Neuroanatomy, hemisphericity and facial asymmetry
Neuropsychologia, Vol. 20, No. 6, PP. 699-701, hinted in Great Bntain.
0028-3932/82/06069943$03.00/0 cs 1982 Pergamon Press Ltd.
1982.
NOTE NEUROANATOMY,
HEMISPHERICITY
AND FACIAL
ASYMMETRY
J. KEVIN THWPSON* School of Medicine/Department
of Psychiatry,
University
(Accepted
13 July 1982)
of Alabama
in Birmingham,
U.S.A
Abstract-A recent paper in this journal (ALFORD and ALFORD, Neuropsychologia, 19,605, 1981) [l] assessed two measures of facial expression (eye winking and eyebrow raising) in the determination of lateralized hemispheric control of emotion. A review of the neuroanatomical basis for the use of these measures determined that the examination of asymmetrical expressions in the assessment of cerebral dominance should be limited to the lower facial musculature.
IN A RECENT
paper in this journal on “Sex differences in asymmetry in the facial expression of emotion,” ALFOKD and ALF~RD [l] utilized two behavioral measures in the assessment of asymmetrical expression of emotion: “preferred eye winking and eyebrow raising facility” (p. 605). They hypothesized, based on previous research indicating (a) a dominant role for the right hemisphere in the perception and expression of emotion, and (b) differences in lateralization of cerebral functions across sex and handedness groups, that the following should be found: “(la) males should exhibit more winking with their left eyes than females; (1 b) this effect should be enhanced if non-right-handers are eliminated from the sample; (2a) males should be more able to wink with their nonpreferred eye than females; (2b) this effect should be enhanced if non-right-handers are eliminated from the sample; (3a) males should show more facility raising their left eyebrows than females; (b) this effect should be enhanced if non-right-handers are eliminated from the sample” [l] p. 606). Unfortunately, the report by ALFORD and ALFORD [l] utilized two measures which do not reflect unilateral hemispheric control of voluntary emotional expressions (subjects were asked by the experimenters to perform the tasks). The control of voluntary facial expressions has generally been accepted to be through corticobulbar pathways beginning in the motor cortex, descending in the internal capsule, and connecting to the nucleus of the facial cranial nerve [Z-4]. Thus, asymmetries ofexpression, indicating accentuation of muscle responses on one side of the face, have been taken to implicate the opposite hemisphere in the control of a particular emotton. However, as pointed out by CARPENTER [S] and others [6-81 there are limitations to this neat neuroanatomical arrangement: “Corticobulbar tibers projecting to cell groups of the facial nucleus innervating muscles in the upper part of the face and forehead are distributed bilaterally; those projecting to cell groups which innervate the lower part of the face are predominately crossed. Thus a lesion interruptingcorticobulbar pathways results in paralysis only of the lower facial muscles contralaterally” [2] p. 128). B~oo~t. [9] has also recently discussed this topic with reference to corticobulbar connections: “From clinical findings it appears that these fibers are crossed, except some of those going to the nuclear division supplying the muscles above and around the eye (see above), since lesions of the corticobulbar tracts, e.g., in hemiplegia result in paralysis of the lower part of the facial muscles only” ([9] p. 498). Therefore, judgments of hemisphericity and facial asymmetry can only be made with accuracy when the lower facial
*Requests for reprints should be sent to: J. Kevin Thompson, Consultation and Liaison Service, Department Psychiatry, University Station/School of Medicine, Birmingham, Al 35294, U.S.A.
of
NOTE
700
muscles are evaluated.* These observations are especially pertinent given the muscles required for the tasks in the and ALF~RD [l] investigation, i.e., the orbicularis oculi (used to close the eyelids), the epicranius (used to raise the eyebrows) and, possibly, the corrugator and procerus (used to draw eyebrows downward) [lo]. The conclusions reached by AI.F~R~ and AI FORD [l] would follow only if these muscles received only contralateral projections from the seventh cranial nerve. Research on hemisphericity and facial expression is an important area of investigation. The significant findings of the ALFORI) and AI.FORD [l] study, although not reflective of cerebral laterality, nevertheless indicate facial dominance in the projection ofexpressions around the eyes. It would be interesting to assess the degree of asymmetry present for spontaneous winking. ALFORD
REFERENCES 1. ALFORD, R. and ALFORD, K. F. Sex differences in asymmetry in the expression of emotion. Nrurops~choloyiu 19, 605-608, 1981. 2. KAHN, E. A. On facial expression. C/in. Neuro.wr,y. 12, 9922, 1966. 3. MIEHLE, A. Surgery of the Facial Nerae. Saunders, Philadelphia, 1973. 4. MYERS, R. E. Comparative neurology of vocalization and speech: proof of a dichotomy. Ann. N. Y. Acnd. Sci. 280, 745p757., 1976. CARPENTER, M. B. Core Texr q/ Neuroanatomy (2nd edn). Williams & Wilkins, Baltimore, 197X. 2: KUYPERS. H. G. J. M. Corticobulbar connections to the pons and lower brainstem in man. An anatomical study. Bruin 81, 364388, 1958. 1. COURVII.LE, H. The nucleus of the facial nerve: The relation between cellular groups and peripheral branches of the nerve. Bruin Res. 1, 338.-354, 1966. 8. SNELL, R. S. Clinical neuroanafomy. Little, Brown, Boston, 1980. 9. BRODAL, A. Neurological anatomy ;n relation to clinical medicine (3rd Edn). Oxford University Press. Oxford, 1981. 1967. IO. QJIRING,Il. P. and WARFEL, J. H. The head, neck. and rrunk (3rd Edn). Lea & Febiger, Philadelphia, of voluntary and emotional innervation in facial paresis of Il. MOVRAD-KROHN, G. H. On the dissociation central origin. Brain 47, 22-35, 1924. 12. MONRAD-KROHN, G. H. On facial dissociation. Acru Psychiut. Neural. &and. 14, 557 566, 1939. 13. IRONSIDE, R. Disorders of laughter due to brain lesions. Bruin 79, 589 -609, 1956.
RESUME
Un article r¢ rians cette Revue wait Ptabli dew parametres de l'expression faciale (clin d'oeil et 61.&ation du sourcil) pour Gterminer l'h6misphCre impliqu6 dans le contr6le des Qmotions. Une revue des bases neuro-anatomiques pour l'utilisation de ces parametres fait apparaitre que l'examen des mimioues asvm&trioues dans 1'6tablissement de la dominance c6rGbral'e deviait P&e limit6 2 la rmsculatlue faciale inf6rieure.
*The situation becomes even more complicated when one considers involuntary (spontaneous) emotions. Available evidence suggests that motor pathways responsible for the mediation of these facial expressions arc different from those discussed previously for voluntary expressions. These differences were first noted systematically by MONRAI)-KROIIU 111, 121 who observed that patients with central facial hemiparesis (loss of voluntary movement on one side of the central portion of the face) could produce a smile of equal intensity on both sides of the face m response to a joke. However, when voluntary facial movement was required (i.e., directly asking the patient to smile) contraction offacial muscles opposite the side of the brain damage was impossible or weakened. Interestingly, he observed the reverse for cases of post-encephalitic Parkinsonism. In these cases, spontaneous expression was impaired while the performance of voluntary expression was intact. As noted, the control of voluntary expression has generally been accepted to be through corticobulbar pathways beginning in the motor cortex, however, various other pathways have been proposed to mediate spontaneous expression such as a pallidobulbar system or corticobulbar pathways of unknown course or direction [Z, 3, 131.
701
NOTE
Zusammenfassung: Eine
kiirzllch
Parameter brauen),
Zeitschrift
\-erdffentlichte
Gesichtsausdruckes
(Augenzwinkern
urn die Laterallsierung
zu bestimmen. Parameter druck
in dicser des
fiir
muskulatur
Ein ze igte,
ijberblick dafl eine
die Feststellung beschrankt
der iiber
Kontrolle
die neuro-anatomischen
der der
Grundlagell
auf Asymmetrien
HemispQirendominanz
sollte.
(1) erfaflte
und Anheben
hemisphXrischen
Untersuchung der
sein
Arbeit
zwei AugenEmotionen dieser
im Gesichtsaus-
auf die untere
Gesichts-
0028-3932/82/06069943$03.00/0 cs 1982 Pergamon Press Ltd.
1982.
NOTE NEUROANATOMY,
HEMISPHERICITY
AND FACIAL
ASYMMETRY
J. KEVIN THWPSON* School of Medicine/Department
of Psychiatry,
University
(Accepted
13 July 1982)
of Alabama
in Birmingham,
U.S.A
Abstract-A recent paper in this journal (ALFORD and ALFORD, Neuropsychologia, 19,605, 1981) [l] assessed two measures of facial expression (eye winking and eyebrow raising) in the determination of lateralized hemispheric control of emotion. A review of the neuroanatomical basis for the use of these measures determined that the examination of asymmetrical expressions in the assessment of cerebral dominance should be limited to the lower facial musculature.
IN A RECENT
paper in this journal on “Sex differences in asymmetry in the facial expression of emotion,” ALFOKD and ALF~RD [l] utilized two behavioral measures in the assessment of asymmetrical expression of emotion: “preferred eye winking and eyebrow raising facility” (p. 605). They hypothesized, based on previous research indicating (a) a dominant role for the right hemisphere in the perception and expression of emotion, and (b) differences in lateralization of cerebral functions across sex and handedness groups, that the following should be found: “(la) males should exhibit more winking with their left eyes than females; (1 b) this effect should be enhanced if non-right-handers are eliminated from the sample; (2a) males should be more able to wink with their nonpreferred eye than females; (2b) this effect should be enhanced if non-right-handers are eliminated from the sample; (3a) males should show more facility raising their left eyebrows than females; (b) this effect should be enhanced if non-right-handers are eliminated from the sample” [l] p. 606). Unfortunately, the report by ALFORD and ALFORD [l] utilized two measures which do not reflect unilateral hemispheric control of voluntary emotional expressions (subjects were asked by the experimenters to perform the tasks). The control of voluntary facial expressions has generally been accepted to be through corticobulbar pathways beginning in the motor cortex, descending in the internal capsule, and connecting to the nucleus of the facial cranial nerve [Z-4]. Thus, asymmetries ofexpression, indicating accentuation of muscle responses on one side of the face, have been taken to implicate the opposite hemisphere in the control of a particular emotton. However, as pointed out by CARPENTER [S] and others [6-81 there are limitations to this neat neuroanatomical arrangement: “Corticobulbar tibers projecting to cell groups of the facial nucleus innervating muscles in the upper part of the face and forehead are distributed bilaterally; those projecting to cell groups which innervate the lower part of the face are predominately crossed. Thus a lesion interruptingcorticobulbar pathways results in paralysis only of the lower facial muscles contralaterally” [2] p. 128). B~oo~t. [9] has also recently discussed this topic with reference to corticobulbar connections: “From clinical findings it appears that these fibers are crossed, except some of those going to the nuclear division supplying the muscles above and around the eye (see above), since lesions of the corticobulbar tracts, e.g., in hemiplegia result in paralysis of the lower part of the facial muscles only” ([9] p. 498). Therefore, judgments of hemisphericity and facial asymmetry can only be made with accuracy when the lower facial
*Requests for reprints should be sent to: J. Kevin Thompson, Consultation and Liaison Service, Department Psychiatry, University Station/School of Medicine, Birmingham, Al 35294, U.S.A.
of
NOTE
700
muscles are evaluated.* These observations are especially pertinent given the muscles required for the tasks in the and ALF~RD [l] investigation, i.e., the orbicularis oculi (used to close the eyelids), the epicranius (used to raise the eyebrows) and, possibly, the corrugator and procerus (used to draw eyebrows downward) [lo]. The conclusions reached by AI.F~R~ and AI FORD [l] would follow only if these muscles received only contralateral projections from the seventh cranial nerve. Research on hemisphericity and facial expression is an important area of investigation. The significant findings of the ALFORI) and AI.FORD [l] study, although not reflective of cerebral laterality, nevertheless indicate facial dominance in the projection ofexpressions around the eyes. It would be interesting to assess the degree of asymmetry present for spontaneous winking. ALFORD
REFERENCES 1. ALFORD, R. and ALFORD, K. F. Sex differences in asymmetry in the expression of emotion. Nrurops~choloyiu 19, 605-608, 1981. 2. KAHN, E. A. On facial expression. C/in. Neuro.wr,y. 12, 9922, 1966. 3. MIEHLE, A. Surgery of the Facial Nerae. Saunders, Philadelphia, 1973. 4. MYERS, R. E. Comparative neurology of vocalization and speech: proof of a dichotomy. Ann. N. Y. Acnd. Sci. 280, 745p757., 1976. CARPENTER, M. B. Core Texr q/ Neuroanatomy (2nd edn). Williams & Wilkins, Baltimore, 197X. 2: KUYPERS. H. G. J. M. Corticobulbar connections to the pons and lower brainstem in man. An anatomical study. Bruin 81, 364388, 1958. 1. COURVII.LE, H. The nucleus of the facial nerve: The relation between cellular groups and peripheral branches of the nerve. Bruin Res. 1, 338.-354, 1966. 8. SNELL, R. S. Clinical neuroanafomy. Little, Brown, Boston, 1980. 9. BRODAL, A. Neurological anatomy ;n relation to clinical medicine (3rd Edn). Oxford University Press. Oxford, 1981. 1967. IO. QJIRING,Il. P. and WARFEL, J. H. The head, neck. and rrunk (3rd Edn). Lea & Febiger, Philadelphia, of voluntary and emotional innervation in facial paresis of Il. MOVRAD-KROHN, G. H. On the dissociation central origin. Brain 47, 22-35, 1924. 12. MONRAD-KROHN, G. H. On facial dissociation. Acru Psychiut. Neural. &and. 14, 557 566, 1939. 13. IRONSIDE, R. Disorders of laughter due to brain lesions. Bruin 79, 589 -609, 1956.
RESUME
Un article r¢ rians cette Revue wait Ptabli dew parametres de l'expression faciale (clin d'oeil et 61.&ation du sourcil) pour Gterminer l'h6misphCre impliqu6 dans le contr6le des Qmotions. Une revue des bases neuro-anatomiques pour l'utilisation de ces parametres fait apparaitre que l'examen des mimioues asvm&trioues dans 1'6tablissement de la dominance c6rGbral'e deviait P&e limit6 2 la rmsculatlue faciale inf6rieure.
*The situation becomes even more complicated when one considers involuntary (spontaneous) emotions. Available evidence suggests that motor pathways responsible for the mediation of these facial expressions arc different from those discussed previously for voluntary expressions. These differences were first noted systematically by MONRAI)-KROIIU 111, 121 who observed that patients with central facial hemiparesis (loss of voluntary movement on one side of the central portion of the face) could produce a smile of equal intensity on both sides of the face m response to a joke. However, when voluntary facial movement was required (i.e., directly asking the patient to smile) contraction offacial muscles opposite the side of the brain damage was impossible or weakened. Interestingly, he observed the reverse for cases of post-encephalitic Parkinsonism. In these cases, spontaneous expression was impaired while the performance of voluntary expression was intact. As noted, the control of voluntary expression has generally been accepted to be through corticobulbar pathways beginning in the motor cortex, however, various other pathways have been proposed to mediate spontaneous expression such as a pallidobulbar system or corticobulbar pathways of unknown course or direction [Z, 3, 131.
701
NOTE
Zusammenfassung: Eine
kiirzllch
Parameter brauen),
Zeitschrift
\-erdffentlichte
Gesichtsausdruckes
(Augenzwinkern
urn die Laterallsierung
zu bestimmen. Parameter druck
in dicser des
fiir
muskulatur
Ein ze igte,
ijberblick dafl eine
die Feststellung beschrankt
der iiber
Kontrolle
die neuro-anatomischen
der der
Grundlagell
auf Asymmetrien
HemispQirendominanz
sollte.
(1) erfaflte
und Anheben
hemisphXrischen
Untersuchung der
sein
Arbeit
zwei AugenEmotionen dieser
im Gesichtsaus-
auf die untere
Gesichts-