title: Tectal afferents in Rana pipiens. A reassessment questioning the comparability of HRP-results.
abstract: Studying afferents to the optic tectum in Rana pipiens by means of retrograde HRP transport, results were obtained, that cast doubt on the reliability of this neuronal tract tracing technique. The tectum was found to receive afferents from e.g. lateral mesencephalic tegmentum, torus semicircularis, contralateral large-celled pretectal nucleus, and ipsilateral thalamic nuclei, which have not previously been demonstrated. In addition, the data obtained lack evidence of projections reported earlier. We suggest, that neuronal projections may be subject to hormone and/or activity dependent changes, that alter the probability of accumulating sufficient amounts of the tracer to become labeled.
authors.affiliation: Department of Anatomy, School of Medicine, University of Goettingen, Federal Republic of Germany.
authors.forename: M H
authors.initials: MH
authors.lastname: Hofmann
authors.forename: S O
authors.initials: SO
authors.lastname: Ebbesson
authors.forename: D L
authors.initials: DL
authors.lastname: Meyer
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D006735:Horseradish Peroxidase; D009475:Neurons, Afferent / Q000648:ultrastructure*; D011894:Rana pipiens; D013477:Superior Colliculi / Q000033:anatomy & histology; D013787:Thalamic Nuclei / Q000033:anatomy & histology
chemical_list: D006735:Horseradish Peroxidase