Hering's law of equal innervation is used to explain the conjugacy of saccadiceye movement in stereoptic animals. The law proposes that conjugacy of saccades is due to innate connections in which the eye muscles responsible for each eye's movements are innervated equally. The law also states that apparent monocular eye movements are actually the summation of conjugate version and disjunctive (or vergence) eye movements. The law was put forward by Ewald Hering in the 19th century,[1] though the underlying principles of the law date back considerably. Aristotle had commented upon this phenomenon and Ptolemy put forward a theory of why such a physiological law might be useful.[2][3] The 11th century scholar Ibn al-Haytham stated that eyes move together and equally so that the visual axes converge on an object of interest in his Book of Optics.[4]
Depiction of predictions for refoveating Muller's stimulus with eyes moving independently or eyes following Hering's law of equal innervation
Hering's law of equal innervation is best understood with Johannes Peter Müller's stimulus where an observer refoveates a point that moved in one eye only. The least-effort way to refoveate is to move the misaligned eye only. Instead Hering's law predicts that because both eyes must move by equal amounts, a combination of conjunctive and disjunctive eye movements is required to refoveate the target point. Yarbus[5] showed experimentally that binocular eyes movements are indeed composed mostly of combinations of saccades and vergence. However, it is now known that clear deviations from Hering's law also occur.[6][7][8]
This theory is in contrast to the theory proposed by Hermann von Helmholtz[9] which states that conjugacy is a learned, coordinated response and that the movements of the eyes are individually controlled. Helmholtz's point of view is today often caricatured as a chameleon-like, independent, control of the eyes although Helmholtz never defended that theory. Their disagreement concerned the innate vs. learned aspect of binocularly coordinated eye movements. Helmholtz's arguments were mainly related to Listing's law and can be simplified as the fact that there exist positions of the eyes where muscles will have different effects on the two eyes. Thus Hering's law, in its original formulation, simply cannot be correct as it would lead to situations where the eyes would move by different amounts, something on which both agreed never happens. Hering subsequently modified his law to state that the eyes behave as if they received equal innervation.
The extent to which Hering's law is correct, or not, remains in debate today, as the exact physiological underpinnings of vergence eye movements remain to be found.[10]
Notesedit
^Hering, Ewald (1977). The theory of binocular vision. New York: Plenum Press. ISBN0-306-31016-3.
^Wade, N. J. (1998). A Natural History of Vision. Cambridge, MA: MIT Press. ISBN0-262-23194-8.
^Howard, I. P.; Wade, N. J. (1996). "Ptolemy's contributions to the geometry of binocular vision". Perception. 25 (10): 1189–201. doi:10.1068/p251189. PMID 9027922. S2CID 34431898.
^Howard, Ian P. (1996). "Alhazen's neglected discoveries of visual phenomena". Perception. 25 (10): 1203–17. doi:10.1068/p251203. PMID 9027923. S2CID 20880413.
^Yarbus, A. L. (1967). Eye Movements and Vision. New York: Plenum Press.
^Pickwell LD (September 1972). "Hering's law of equal innervation and the position of the binoculus". Vision Res. 12 (9): 1499–507. doi:10.1016/0042-6989(72)90175-7. PMID 5073145.
^Bahill AT, Ciuffreda KJ, Kenyon R, Stark L (December 1976). "Dynamic and static violations of Hering's law of equal innervation". Am J Optom Physiol Opt. 53 (12): 786–96. doi:10.1097/00006324-197612000-00005. PMID 1015527. S2CID 11881312.
^Enright J. T. (1984). "Changes in vergence mediated by saccades". J Physiol. 350: 9–31. doi:10.1113/jphysiol.1984.sp015186. PMC1199254. PMID 6747862.
^Helmholtz, H. (1910). Treatise on Physiological Optics. New York: Dover. ISBN1-85506-831-1.
^Michael J. Aminoff, Robert B. Daroff, ed. (2014). "Hering, Ewald". Encyclopedia of the Neurological Sciences, Volume 1. Elsevier Science. p. 552. ISBN9780123851581.
Sourcesedit
Hering, Ewald (1977). Stark, Lawrence; Bridgeman, Bruce (eds.). The theory of binocular vision. Bridgeman, Bruce. New York: Plenum Press. ISBN0-306-31016-3.
Helmholtz, H. (1910). Treatise on Physiological Optics. New York: Dover. ISBN1-85506-831-1.
Yarbus, A. L. (1967). Eye Movements and Vision. New York: Plenum Press.
Pickwell LD (September 1972). "Hering's law of equal innervation and the position of the binoculus". Vision Res. 12 (9): 1499–507. doi:10.1016/0042-6989(72)90175-7. PMID 5073145.
Bahill AT, Ciuffreda KJ, Kenyon R, Stark L (December 1976). "Dynamic and static violations of Hering's law of equal innervation". Am J Optom Physiol Opt. 53 (12): 786–96. doi:10.1097/00006324-197612000-00005. PMID 1015527. S2CID 11881312.
Enright J.T. (1984). "Changes in vergence mediated by saccades". J Physiol. 350: 9–31. doi:10.1113/jphysiol.1984.sp015186. PMC1199254. PMID 6747862.
hering, equal, innervation, used, explain, conjugacy, saccadic, movement, stereoptic, animals, proposes, that, conjugacy, saccades, innate, connections, which, muscles, responsible, each, movements, innervated, equally, also, states, that, apparent, monocular,. Hering s law of equal innervation is used to explain the conjugacy of saccadic eye movement in stereoptic animals The law proposes that conjugacy of saccades is due to innate connections in which the eye muscles responsible for each eye s movements are innervated equally The law also states that apparent monocular eye movements are actually the summation of conjugate version and disjunctive or vergence eye movements The law was put forward by Ewald Hering in the 19th century 1 though the underlying principles of the law date back considerably Aristotle had commented upon this phenomenon and Ptolemy put forward a theory of why such a physiological law might be useful 2 3 The 11th century scholar Ibn al Haytham stated that eyes move together and equally so that the visual axes converge on an object of interest in his Book of Optics 4 Depiction of predictions for refoveating Muller s stimulus with eyes moving independently or eyes following Hering s law of equal innervationHering s law of equal innervation is best understood with Johannes Peter Muller s stimulus where an observer refoveates a point that moved in one eye only The least effort way to refoveate is to move the misaligned eye only Instead Hering s law predicts that because both eyes must move by equal amounts a combination of conjunctive and disjunctive eye movements is required to refoveate the target point Yarbus 5 showed experimentally that binocular eyes movements are indeed composed mostly of combinations of saccades and vergence However it is now known that clear deviations from Hering s law also occur 6 7 8 This theory is in contrast to the theory proposed by Hermann von Helmholtz 9 which states that conjugacy is a learned coordinated response and that the movements of the eyes are individually controlled Helmholtz s point of view is today often caricatured as a chameleon like independent control of the eyes although Helmholtz never defended that theory Their disagreement concerned the innate vs learned aspect of binocularly coordinated eye movements Helmholtz s arguments were mainly related to Listing s law and can be simplified as the fact that there exist positions of the eyes where muscles will have different effects on the two eyes Thus Hering s law in its original formulation simply cannot be correct as it would lead to situations where the eyes would move by different amounts something on which both agreed never happens Hering subsequently modified his law to state that the eyes behave as if they received equal innervation The extent to which Hering s law is correct or not remains in debate today as the exact physiological underpinnings of vergence eye movements remain to be found 10 Notes edit Hering Ewald 1977 The theory of binocular vision New York Plenum Press ISBN 0 306 31016 3 Wade N J 1998 A Natural History of Vision Cambridge MA MIT Press ISBN 0 262 23194 8 Howard I P Wade N J 1996 Ptolemy s contributions to the geometry of binocular vision Perception 25 10 1189 201 doi 10 1068 p251189 PMID 9027922 S2CID 34431898 Howard Ian P 1996 Alhazen s neglected discoveries of visual phenomena Perception 25 10 1203 17 doi 10 1068 p251203 PMID 9027923 S2CID 20880413 Yarbus A L 1967 Eye Movements and Vision New York Plenum Press Pickwell LD September 1972 Hering s law of equal innervation and the position of the binoculus Vision Res 12 9 1499 507 doi 10 1016 0042 6989 72 90175 7 PMID 5073145 Bahill AT Ciuffreda KJ Kenyon R Stark L December 1976 Dynamic and static violations of Hering s law of equal innervation Am J Optom Physiol Opt 53 12 786 96 doi 10 1097 00006324 197612000 00005 PMID 1015527 S2CID 11881312 Enright J T 1984 Changes in vergence mediated by saccades J Physiol 350 9 31 doi 10 1113 jphysiol 1984 sp015186 PMC 1199254 PMID 6747862 Helmholtz H 1910 Treatise on Physiological Optics New York Dover ISBN 1 85506 831 1 Michael J Aminoff Robert B Daroff ed 2014 Hering Ewald Encyclopedia of the Neurological Sciences Volume 1 Elsevier Science p 552 ISBN 9780123851581 Sources editHering Ewald 1977 Stark Lawrence Bridgeman Bruce eds The theory of binocular vision Bridgeman Bruce New York Plenum Press ISBN 0 306 31016 3 Helmholtz H 1910 Treatise on Physiological Optics New York Dover ISBN 1 85506 831 1 Yarbus A L 1967 Eye Movements and Vision New York Plenum Press Pickwell LD September 1972 Hering s law of equal innervation and the position of the binoculus Vision Res 12 9 1499 507 doi 10 1016 0042 6989 72 90175 7 PMID 5073145 Bahill AT Ciuffreda KJ Kenyon R Stark L December 1976 Dynamic and static violations of Hering s law of equal innervation Am J Optom Physiol Opt 53 12 786 96 doi 10 1097 00006324 197612000 00005 PMID 1015527 S2CID 11881312 Enright J T 1984 Changes in vergence mediated by saccades J Physiol 350 9 31 doi 10 1113 jphysiol 1984 sp015186 PMC 1199254 PMID 6747862 See also editSherrington s law of reciprocal innervation Dissociated vertical deviation Orthoptics Retrieved from https en wikipedia org w index php title Hering 27s law of equal innervation amp oldid 1148102705, wikipedia, wiki, book, books, library,
