Fiber connections of the periventricular pretectal nucleus were studied by a tract-tracing method in a teleost
tilapia. After tracer injections into the periventricular pretectal nucleus
labeled neurons were observed ipsilaterally in the area pretectalis pars ventralis
area pretectalis pars dorsalis
optic tectum and ventrolateral nucleus of semicircular torus
bilaterally in the ventromedial thalamic nucleus
principal sensory trigeminal nucleus and descending trigeminal nucleus
and contralaterally in the periventricular pretectal nucleus and corpus cerebelli. Two types of tectal neurons were labeled in the stratum album centrale and the stratum periventriculare. The somata in the stratum album centrale were large and oval or multipolar. The somata in the stratum periventriculare were pyriform with an apical dendrite that ramified at the boundary zone between the stratum griseum centrale and stratum fibrosum et griseum superficiale. Anterogradely labeled terminals were present in the ipsilateral area pretectalis pars dorsalis
optic tectum and corpus cerebelli
the bilateral ventromedial thalamic nucleus
lateral valvular nucleus
oculomotor nucleus and inferior olive
and the contralateral periventricular pretectal nucleus. The present study suggests that the periventricular pretectal nucleus conveys somatosensory and mechanosensory lateral line inputs in addition to the visual information to the cerebellum. c 2006 Elsevier Ireland Ltd and the Japan Neuroscience Society.
