[Changes of the ventral dendrite of a goldfish Mauthner neurons induced by optokinetic stimulation]

It was recently demonstrated that following the optomotor drum, rotating contralaterally to the turn side, spontaneously preferred by the goldfish fry, inverted their motor asymmetry. The study of Mauthner neuron (MN) structure using the histological method of 3D reconstruction, and the measurements of right and left MN in these fishes, has detected the 3-fold decrease of the volume of the ventral dendrite (VD) of ipsilateral MN, which was reciprocally related to MN functional activity. At the same time, total volume of contralateral MN remained larger than that of ipsilateral one by one quarter, which was the case in intact fishes. It is suggested that the decrease in the size of VD, which receives the afferentation from the contralateral eye, that follows the moving stripes of the optomotor drum, is the result of a specific contralateral visual stimulation and is the first evidence of the possibility of MN natural stimulation through VD.