BEHAVIORAL LATERALIZATION OF THE TETRAPOD TYPE IN THE ZEBRAFISH (BRACHYDANIO-RERIO)

Visual lateralisation resembling that found in a bird (domestic chick) is here demonstrated in a teleost (zebrafish, Brachydanio rerio). Zeb rafish predominantly view objects with the body axis close to facing t he object (0-20 degrees on either side of facing). Strange objects wer e viewed at first exposure chiefly with the right frontal field; so wa s a complex and unfamiliar scene made up of familiar components. In a second trial, using the same stimulus or scene, left frontal viewing t ended to be used instead. A familiar partner (a fish of another specie s) was viewed left frontally. The domestic chick also uses the left ey e to view familiar stimuli, shifting to the right when it has to decid e what response is appropriate to the object at which it is looking. A n empty scene in which nothing could be concealed (and so no response was called for) was viewed by zebrafish with the left eye from the sta rt. In zebrafish and the chick, the right eye is used when it is neces sary to inhibit premature response, in order to sustain viewing until a decision is reached, and the left is used when it is necessary to ke ep an eye on a familiar or clearly empty scene. The findings suggest h omology of cerebral lateralisation in teleost fish and tetrapods. (C) 1998 Elsevier Science Inc.