Autismus und Sehen « Le Syndrome de Schorderet- Munier ... - ophta

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ORIGINALIA For pigeons to maximally benefit from the information-processing «biases» of both hemispheres, logic would dictate for them to alternate the eye performing primary, information-gathering. A moreforward-oriented observation period of 7 to 8 seconds per view would seem reasonbeing of the divergence-excess (excessive innervation of the lateral rectus muscle) or convergence-weakness (diminished innervation of the medial rectus muscle) types. With advancing age, the tendency to diverge increases, and the deviation becomes constant and permanent. An alternating divergence tends to result. 7 This condition has been reported to manifest itself through corporal or emotional stress, including insomnia due to shock, mental duress, or illnesses with high fever, such as mumps, measles, etc. Once the illness or stress has passed, the strabismus has become an acquired habit. 8 In many cases, one eye becomes dominant, 9 but, when both eyes remain about equally «competitive», alternation can result. 10 Thus, exophoria is often accompanied in humans by binocular alternation: Thus, they gaze at their listener first with one eye, then, with the other. Individually, each eye has normal function, but only alternately (Figure 11a-b). Morphometrical Review – Animal Studies Eye-head coordination occurs in monkeys and cats «when a visual target cannot be foveated by an eye-and-head movement because it is too eccentric...the body is turned». 13 According to Walls, granivorous birds never have over 25° of binocularity, and many have less than 10°. It seems that «most birds have little or no spontaneous (eye) mobility, relying upon the flexibility of the neck». 14 Even the shape of pigeon eyes hinders more than modest mobility (cf. Figures 12a,b). Close observation revealed that «birds in flight are commonly observed to tilt the head on one side to look down to the ground monocularly». 15 The homing pigeon, for instance, has been found to have a 24° binocular field upon full convergence (Figure 12c), with a total field of 340° – 342°. 16 In discussing «eye-mindedness», Walls implies that granivorous birds do not «need» binocularity to perceive their food with sufficient accuracy to feed. 17 What advantage could homing pigeons possibly gain from combining left- and right-eye information garnered from gaze alternation during flight? In studies on lateralization of information-processing in pigeon brains, a remarkably distinct asymmetry has been noted. 18–20 Ulrich et al. determined a pronounced left hemispheric superiority for visuospatial orientation in homing pigeons. The opposite is true in the right hemisphere, where higher resolution seems to predominate. The right eye provides the left hemisphere with information; the left eye does so for the right hemisphere. a b b a c Fig. 12a–c Schematic of proportional eye cross-sections and shapes in human (a) and pigeons (b); schematic of juxtaposition of pigeon eyes in the skull (c). Fig. 11a–b Schematic of human exophoric alternation of right- and left-eye gaze. Clinical alternating exophoria and «sidedness» Visual field temporal characteristics in binocular rivalry were observed to conform to handedness in humans. In righthanded persons, responses were faster when visual stimuli were presented to the right visual field, in left-handed persons, the opposite held true. 11 Asymmetries in binocular coordination were also seen in alternating exophoria. 12 Fig. 13a–b Schematic of a visual-mechanical explanation of head-turning alternation contributing to regular undulations in flight-path. ably adequate. Pigeon flight is just that, not gliding; most of the time they flap their wings continually. Thus, by turning their heads from side-to-side to fully exploit their «exophoric» and «visual lateralization» maximally, pigeons could inadvertently impart rhythmic asymmetry to their flight exertions, and, thus, to their flightpath (Figure 13). Try walking straight with your head and hips turned to one side. 270 ophta • 4|2008
ORIGINALIA Fig. 14 Tracing of group-released flock of five pigeons. Pigeon 827 broke away. Pigeons are social creatures, hence, usually fly in groups. In another set of GPStracked group-flying pigeon flocks, individual alternating behavior seemed subordinated to that of the flock, at least until an individual pigeon – for whatever reason – breaks away from the flock to pursue independent flight. Flight-tracks of group-flying flocks show smooth, «disciplined», and efficient curves (Figure 14), compared to the track of an individual pigeon which has just abandoned the group, immediately reverting to undulations (and far less «discipline»). Dedication Dedicated to the fond memory of Professor Roland Brückner, who kindly and patiently taught the first author (ph) to be alert to visual aspects of avian behavior. Fig. 15 Pigeon 904, safely landed at its home loft at Testa di Lepre, ca 25 km NW of Rome, after another experimental homing flight from 20 km out at sea. References 1 Gagliardo A, Ioalè P, Savini M, Lipp HP, Dell’Omo G. Finding home: the final step of the pigeon’s homing process studied with a GPS data logger. J Exp Biol 2007 Apr;210(pt7): 1132–8. 2 Lipp HP, Vyssotski AL, Wolfer DP, Renaudineau S, Savini M, Tröster G, Dell’Omo G. Pigeon homing along highways and exits. Curr Biol 2004 Jul 27; 14(14):1239–49. 3 Lage A, Vyssotski AL, Wolfer DP, Marionneau R, Dell’Omo G, Lipp HP. GPS and EEG analysis of pigeon homing over water and land (in preparation 2009). 4 Steiner I, Bürgi C, Werffeli S, Dell’Omo G, Valenti P, Tröster G, Wolfer DP, Lipp HP. A GPS logger and software for analysis of homing in pigeons and small animals. Physiol Behav 2000 Dec; 71(5): 589–96. 5 Vyssotski AL, Serkov AN, Itskov PM, Dell’Omo G, Latanov AV, Wolfer DP, Lipp HP. Miniature neurologgers for flying pigeons: multichannel EEG and action and field potentials in combination with GPS recording. J Neurophysiol 2006 Feb; 95(2): 1263–73. 6 Kaufmann H. Strabismus, p.200, Ferdinand Enke Publishers, Stuttgart, 1995. 7 Duke-Elder S. System of Ophthalmology, V.6: Ocular Motility and Strabismus, p.620–5, Henry Kimpton Publishers, London, 1973. 8 Brückner R. Das schielende Kind, p.24, Schwabe & Co, Publishers, Basel/Stuttgart, 1976. 9 Ibid, p.25. 10 Ibid, p.29. 11 Chen X, He S. Temporal characterization of binocular rivalry: visual field asymmetries. Vision Res. 2003 Sep; 43(21):2207–12. 12 van Leeuwen AF, Collewijn H, de Faber JT, van der Stehen J. Saccadic binocular coordination in alternating exophoria. Vision Res. 2001; 41(25–26): 3425–35. 13 Berthoz, A. Adaptive mechanisms in eye-head coordination. in Adaptive Mechanisms in Gaze Control. p.184 Elsevier Publishers, Amsterdam, New York, London, 1985. 14 Walls, GL: The Vertebrate Eye and its Adaptive Radiations. p.307, Hafner Publishers, New York, 1963. 15 Ibid, p. 310. 16 Ibid, p. 295. 17 Ibid, p. 323. 18 Diekamp B, Prior H, Ioalè P, Güntürkün O, Gagliardo A. Effects of monocular viewing on orientation in an arena at the release site and homing performance in pigeons. Behav Brain Res 2002 Oct 17; 136(1): 103–11. 19 Prior H, Wiltschko R, Stapput K, Güntürkün O, Wiltschko W. Visual lateralization and homing in pigeons. Behav Brain Res 2004 Oct 5; 154(2): 301–10. 20 Ulrich C, Prior H, Duka T, Leschchins’ka I, Valenti P, Güntürkün O, Lipp HP. Left hemispheric superiority for visuospatial orientation in homing pigeons. Behav Brain Res. 1999 Oct; 104(1–2):169–78. Correspondence: Priv. Doz. Dr. phil. II Phillip Hendrickson Sierenzerstrasse 21, 4055 Basel Tel. 079 764 1135 oroswiss@gmail.com ophta • 4|2008 271
Seite 1 und 2: ISSN 1420-6838 Schweizerische Fach
Seite 3 und 4: EDITORIAL New Concept C’est deven
Seite 5 und 6: ORIGINALIA Autismus und Sehen Doris
Seite 7 und 8: ORIGINALIA R.N. Zu Beginn litt ich
Seite 9 und 10: ORIGINALIA Die Sakkade führt die N
Seite 11 und 12: ORIGINALIA Folgerung Ein grosser T
Seite 13: ORIGINALIA a b c d e f Fig. 6a
Seite 17 und 18: EPILOGUE nous retrouvons également
Seite 19 und 20: KONGRESSE /CONGRES Die Zentren benu
Seite 21 und 22: KONGRESSE /CONGRES Behandlung Zwei
Seite 23 und 24: KONGRESSE /CONGRES Moorfields Inter
Seite 25 und 26: KONGRESSE /CONGRES Tableau 1 Applic
Seite 27 und 28: KONGRESSE /CONGRES Welche Keratopla
Seite 29 und 30: HISTOIRE A. Franceschetti (1896 -19
Seite 31 und 32: HISTOIRE Fig. 3 Franceschetti peint
Seite 33 und 34: ophtaSZENE Ein gutes Jahr für die
Seite 35: ophtART Dr. Faried Esmail Vita Dr.

Autismus und Sehen « Le Syndrome de Schorderet- Munier ... - ophta

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