Projections of the optic tectum in two teleost species.

摘要: The efferent pathways of the optic tectum have been investigated in percomorph Eugerres and berycomorph Holocentrus. A portion dorsal-dorsolateral region was unilaterally resected by suction. animals were perfused 6–30 days thereafter, brains processed according to a modification (Method 7 Ebbesson, '70) Fink-Heimer ('67) technique for selective silver impregnation degenerating axons terminals. Three groups fibers emerge from lesioned region: (a) medial group, which runs towards midline terminates ipsilateral torus longitudinalis contralateral tectum; (b) an ascending enters dorsocaudal diencephalon pretectal cell groups, dorsomedial thalamic nucleus, nucleus rotundus or prethalamicus; (c) descending funnels down into midbrain tegmentum. Here abundant terminals are given dorsolateral isthmi. recurrent fascicle leaves mainstream ascends terminate scattered diencephalic geniculatus posterior pars ventralis, prethalamicus. bulk then forms bundle, gives lateral reticular formation mesencephalon rhombencephalon, (i.e., predorsal) rhombencephalon.