Giant lateral-line afferent terminals in the electroreceptive dorsal nucleus of lampreys

In HRP studies of the lateral line nerve in lampreys, the dorsal nucleus of the area octavolateralis received projections mainly from the recurrent branch of the anterior lateral line nerve. Furthermore, the recurrent branch projected exclusively to the dorsal nucleus. Besides the common type (1-3 micron) of nerve terminals, a hitherto unreported type of giant (10-30 micron) nerve terminal was found aggregated at the rostral and caudal ends of the nucleus. Since the dorsal nucleus mediates electroreception in lampreys, we conclude that the giant terminals are very probably the terminals of the electroreceptive primary fibers.