Input and output characteristics of collision avoidance behavior in the bullfrog were examined using computer graphics to model a looming stimulus. The means of time-to-collision of avoidance behavior in response to looming visual stimuli approaching at a velocity of either 2 or 4 m/s were significantly different (t(141) = 7.93, p < 0.05). On the other hand, mean threshold sizes of visual stimuli triggering avoidance behavior were not significantly different in either case (t(201) = 0.54, p > 0.05). Furthermore, we showed that the mean threshold sizes changed in a predictable manner depending on the distance between the displayed stimulus and the animal. These results strongly suggest that the frog displays collision avoidance behavior when the visual angle of a looming object reaches a constant value (about 20°). The mean maximum velocities of the avoidance behavior in response to the two visual stimuli were not significantly different (t(198) = 1.44, p > 0.05). However, we found that the frog could control the velocity depending on the location of an approaching object in its dorsal visual field. Finally, we demonstrated that habituation significantly affected the mean probability of avoidance behavior occurrence (ANOVA, at 2 m/s, F(2,15) = 14.25; at 4 m/s, F(2,15) = 13.35, p < 0.05), but not those of time-to-collision, threshold size and maximum velocity (ANOVA, at 2 m/s, F(2,13) = 0.07, F(2,14) = 0.46 and F(2,14) = 0.70, respectively; at 4 m/s, F(2,15) = 0.50, F(2,14) = 0.68 and F(2,14) = 0.41, respectively, p > 0.05). Thus, frog collision avoidance behavior seems to have an all or none – like property.

1.
Ball W, Tronick E (1971) Infant responses to impending collision: Optical and real. Science 171:818–820.
2.
Ewert JP (1971) Single unit response of the toad’s (Bufo americanus) caudal thalamus to visual objects. Z Vergl Physiol 74:81–102.
3.
Ewert JP (1984) Tectal mechanisms that underlie prey-catching and avoidance behaviors in toads. In: Comparative Neurology of the Optic Tectum (Vanegas H, ed), pp 247–416. New York, London: Plenum Press.
4.
Ewert JP, Burghagen H (1979) Ontogenetic aspects on visual ‘size-constancy’ phenomena in the midwife toad Alytes obstetricans (Laur.). Brain Behav Evol 16:99–112.
5.
Gabbiani F, Krapp HG, Laurent G (1999) Computation of object approach by a wide-field, motion-sensitive neuron. J Neurosci 19:1122–1141.
6.
Gabbiani F, Mo C, Laurent G (2001) Invariance of angular threshold computation in a wide-field looming-sensitive neuron. J Neurosci 21:314–329.
7.
Gaze RM (1958) The representation of the retina on the optic lobe of the frog. Q J Exp Physiol 43:209–214.
8.
Gaze RM, Jacobson M (1962) The projection of the binocular visual field on the optic tecta of the frog. Q J Exp Physiol 47:273–280.
9.
Gibson JJ (1979) The Ecological Approach to Visual Perception. Boston MA: Houghton Mifflin.
10.
Grant AC, Lettvin JY (1991) Sources of electrical transients in tectal neuropil of the frog. Brain Res 560:106–121.
11.
Grüsser OJ, Grüsser-Cornehls U (1976) Neurophysiology of the anuran visual system. In: Frog Neurobiology (Llinás R, Precht W, eds), pp 297–385. Berlin, Heidelberg, New York: Springer Verlag.
12.
Hatsopoulos N, Gabbiani F, Laurent G (1995) Elementary computation of object approach by a wide-field visual neuron. Science 270:1000–1003.
13.
Hayes WN, Saiff EI (1967) Visual alarm reactions in turtles. Anim Behav 15:102–106.
14.
Holmqvist MH, Srinivasan MV (1991) A visually evoked escape response of the housefly. J Comp Physiol A 169:451–459.
15.
Ingle D (1973) Two visual systems in the frog. Science 181:1053–1055.
16.
Ingle D (1977) Detection of stationary objects by frogs following optic tectum ablation. J Comp Physiol Psychol 91:1359–1364.
17.
Ingle D (1991) Control of frog evasive direction: triggering and biasing systems. In: Visual Structures and Integrated Functions (Arbib MA, Ewert JP, eds), pp 181–189. Berlin, Heidelberg: Springer Verlag.
18.
Ingle DJ, Hoff K vS (1990) Visually elicited evasive behavior in frogs. Bioscience 40:284–291.
19.
Judge SJ, Rind FC (1997) The locust DCMD, a movement-detecting neurone tightly tuned to collision trajectories. J Exp Biol 200:2209–2216.
20.
King JR, Comer CM (1996) Visually elicited turning behavior in Rana pipiens: Comparative organization and neural control of escape and prey capture. J Comp Physiol A 178:293–305.
21.
King JG, Lettvin JY, Gruberg ER (1999) Selective, unilateral, reversible loss of behavioral responses to looming stimuli after injection of tetrodotoxin or cadmium chloride into the frog optic nerve. Brain Res 841:20–26.
22.
Kostyk SK, Grobstein P (1982) Visual orienting deficits in frogs with various unilateral lesions. Behav Brain Res 6:379–388.
23.
Kostyk SK, Grobstein P (1987a) Neuronal organization underlying visually elicited prey orienting in the frog – I. Effects of various unilateral lesions. Neuroscience 21:41–55.
24.
Kostyk SK, Grobstein P (1987b) Neuronal organization underlying visually elicited prey orienting in the frog – II. Anatomical studies on the laterality of central projections. Neuroscience 21:57–82.
25.
Kostyk SK, Grobstein P (1987c) Neuronal organization underlying visually elicited prey orienting in the frog – III. Evidence for the existence of an uncrossed descending tectofugal pathway. Neuroscience 21:83–96.
26.
Lee DN (1976) A theory of visual control of braking based on information about time-to-collision. Perception 5:437–459.
27.
Lee DN, Reddish PE (1981) Plummeting gannets: A paradigm of ecological optics. Nature 293:293–294.
28.
Lee DN, Young DS (1985) Visual timing of interceptive action. In: Brain Mechanisms and Spatial Vision (Ingle DJ, Jeannerod M, Lee DN, eds), pp 1–30. Dordrecht: Martinus Nijhoff.
29.
Lee DN, Davies MNO, Green PR, Weel FRVD (1993) Visual control of velocity of approach by pigeons when landing. J Exp Biol 180:85–104.
30.
Lettvin JY, Maturana HR, McCulloch WS, Pitts WH (1959) What the frog’s eye tells the frog’s brain. Proc I R E 47:1940–1951.
31.
Liaw J, Arbib MA (1991) A neural network model for response to looming objects by frog and toad. In: Visual Structures and Integrated Functions (Arbib MA, Ewert JP, eds), pp 167–180. Berlin, Heidelberg: Springer Verlag.
32.
Masino T, Grobstein P (1989a) The organization of descending tectofugal pathways underlying orienting in the frog, Rana pipiens. I. Lateralization, parcellation, and an intermediate spatial representation. Exp Brain Res 75:227–244.
33.
Masino T, Grobstein P (1989b) The organization of descending tectofugal pathways underlying orienting in the frog, Rana pipiens. II. Evidence for the involvement of a tecto-tegmento-spinal pathway. Exp Brain Res 75:245–264.
34.
Nakagawa H, Matsumoto N (2001) Spatiotemporal pattern of presynaptic terminal activity across the retinotopic map of the frog optic tectum in response to expansion of retinal image. 6th International Congress of Neuroethology Abstracts: 82.
35.
Potter HD (1969) Structural characteristics of cell and fiber populations in the optic tectum of the frog (Rana catesbeiana). J Comp Neurol 136:203–232.
36.
Regan D, Beverley KI (1978) Looming detectors in the human visual pathway. Vision Res 18:415–421.
37.
Regan D, Beverley KI (1979) Binocular and monocular stimuli for motion in depth: Changing-disparity and changing-size feed the same motion-in-depth stage. Vision Res 19:1331–1342.
38.
Regan D, Cynader M (1979) Neurons in area 18 of cat visual cortex selectively sensitive to changing size: Nonlinear interactions between responses to two edges. Vision Res 19:699–711.
39.
Regan D, Hamstra SJ (1993) Dissociation of discrimination thresholds for time to contact and for rate of angular expansion. Vision Res 4:447–462.
40.
Rind FC, Simmons PJ (1992) Orthopteran DCMD neuron: A reevaluation of responses to moving objects. I. Selective responses to approaching objects. J Neurophysiol 68:1654–1666.
41.
Rind FC, Simmons PJ (1997) Signaling of object approach by the DCMD neuron of the locust. J Neurophysiol 77:1029–1033.
42.
Robertson RM, Johnson AG (1993) Retinal image size triggers obstacle avoidance in flying locusts. Naturwissenschaften 80:176–178.
43.
Schiff W (1965) Perception of impending collision: A study of visually directed avoidant behavior. Psychol Monogr 79:1–26.
44.
Schiff W, Caviness JA, Gibson JJ (1962) Persistent fear responses in rhesus monkeys to the optical stimulus of ‘looming’. Science 136:982–983.
45.
Simmons PJ, Rind FC (1992) Orthopteran DCMD neuron: A reevaluation of responses to moving objects. II. Critical cues for detecting approaching objects. J Neurophysiol 68:1667–1682.
46.
Spreckelsen C, Schürg-Pfeiffer E, Ewert JP (1995) Responses of retinal and tectal neurons in non-paralyzed toads Bufo bufo and B. marinus to the real size versus angular size of objects moved at variable distance. Neurosci Lett 184:105–108.
47.
Sun H, Frost BJ (1998) Computation of different optical variables of looming objects in pigeon nucleus rotundus neurons. Nature Neurosci 1:296–303.
48.
Székely G, Lázár G (1976) Cellular and synaptic architecture of the optic tectum. In: Frog Neurobiolgy (Llinás R, Precht W, eds), pp 407–434. Berlin, Heidelberg, New York: Springer Verlag.
49.
Tanaka K, Fukada Y, Saito H (1989) Underlying mechanisms of the response specificity of expansion/contraction and rotation cells in the dorsal part of the medial superior temporal area of the macaque monkey. J Neurphysiol 62:642–656.
50.
Vanegas H (ed) (1984) Comparative Neurology of the Optic Tectum. New York: Plenum Press.
51.
Wagner H (1982) Flow-field variables trigger landing in flies. Nature 297:147–148.
52.
Waldeck RF, Gruberg ER (1995) Studies on the optic chiasm of the leopard frog. I. Selective loss of visually elicited avoidance behavior after optic chiasm hemisection. Brain Behav Evol 46:84–94.
53.
Wang Y, Frost BJ (1992) Time to collision is signaled by neurons in the nucleus rotundus of pigeons. Nature 356:236–238.
54.
Wang Y, Jiang S, Frost BJ (1993) Visual processing in pigeon nucleus rotundus: Luminance, color, motion, and looming subdivisions. Vis Neurosci 10:21–30.
55.
Wicklein M, Strausfeld NJ (2000) Organization and significance of neurons that detect change of visual depth in the hawk moth Manduca sexta. J Comp Neurol 424:356–376.
56.
Zeki SM (1974) Cells responding to changing image size and disparity in the cortex of the rhesus monkey. J Physiol 242:827–841.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.