DEVELOPMENTAL PROCESS OF VISUAL-PATTERN DISCRIMINATION IN THE FLY

It has been found that the development of visual pattern discrimination in the fly is strongly influenced by visual experience in the early stage of post-emergence. Behavioral experiments were performed to determine the details of the temporal conditions of the visual experience and to obtain a lead to the determination of the molecular mechanism underlying the developmental process. By anesthetizing the flies with chilling at various periods post-emergence, it was demonstrated that visual experience during 5 h post-emergence must be followed by normal neuronal activity within a very short time of 15 min for the normal development of visual pattern discrimination to occur. The subsequent development of normal pattern discrimination required the maintenance of normal neuronal activity for at least 5 h. Injection of some protein synthesis inhibitors to the fly head before or immediately after visual experience resulted in impairment of the development of visual pattern discrimination, thus supporting the developmental process revealed by the chilling experiment. Moreover, both the chilling experiment and injection of inhibitors of protein synthesis showed that the neuronal mechanisms were different for phototaxis and for protein discrimination, suggesting that the former is a natural function while the latter is an acquired function after emergence. © 1990.