Altered visual experience and acute visual deprivation affect predatory targeting by infrared-imaging Boid snakes

Ms. Grace et Om. Woodward, Altered visual experience and acute visual deprivation affect predatory targeting by infrared-imaging Boid snakes, BRAIN RES, 919(2), 2001, pp. 250-258
Citations number
Categorie Soggetti
Neurosciences & Behavoir
Journal title
ISSN journal
0006-8993 → ACNP
Year of publication
250 - 258
SICI code
Boid and Crotaline snakes use both their eyes and infrared-imaging facial p it organs to target homeothermic prey. These snakes can target in complete darkness, but the eyes can also effectively direct predatory strikes. We in vestigated the behavioral correlates of boid snakes' simultaneous use of tw o imaging systems by testing whether congenital unilateral visual deprivati on affects targeting performance. Normally sighted Burmese pythons exhibite d average targeting angle of zero (on the midline axis of the head), but th ree unilaterally anophthalmic Burmese pythons targeted preferentially on th e sighted side. A unilaterally anophthalmic amethystine python also targete d on the sighted side, and a unilaterally anophthalmic Brazilian rainbow bo a tended to target on the sighted side, though its mean targeting angle was not significantly different from zero. When unilaterally anophthalmic Burm ese pythons were temporarily blinded, mean strike angle changed to that of normally sighted snakes. These results show that while infrared-imaging sna kes can shift between visual and infrared information under acute experimen tal conditions, loss of part of the visual field during development results in abnormal predatory targeting behavior. In contrast, normally sighted sn akes subjected to temporary unilateral blinding do not target preferentiall y on the sighted side. Therefore, while loss of part of the visual field ma y be compensated for by infrared input in normal snakes, partial absence of visual input during development may alter central organization of visual i nformation. Conversely, absence of half the visual field during development does not alter targeting performance based upon infrared input alone, sugg esting that organization of the central infrared map does not depend upon n ormal organization of visual input. (C) 2001 Elsevier Science B.V. All righ ts reserved.