title: Connections between the central posterior/prepacemaker nucleus and hypothalamic areas in the weakly electric fish Apteronotus leptorhynchus: evidence for an indirect, but not a direct, link.
abstract: The central posterior/prepacemaker nucleus (CP/PPn) of the weakly electric fish Apteronotus leptorhynchus consists of a few thousands of neurons in the dorsal thalamus. Subpopulations of this complex play a crucial role in neural control of transient modulations of the otherwise extremely constant electric organ discharges. Because both the propensity to execute these modulations and the type of modulations produced may vary enormously with the behavioral situation, it has been hypothesized that this behavioral plasticity is, partially, mediated by peptidergic neuromodulators originating from hypothalamic areas. To define the structural basis of this proposed modulatory input, we have in the present study examined the connections between the CP/PPn proper and hypothalamic areas by employing an in vitro tract-tracing technique. Neither anterograde nor retrograde tracing experiments could provide evidence for the existence of a direct link between the CP/PPn proper and hypothalamic areas. However, the results of our investigation suggest an indirect connection between the CP/PPn proper and two hypothalamic regions, the hypothalamus ventralis and the hypothalamus lateralis, with the preglomerular nucleus serving as a relay station.
authors.affiliation: School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom.
authors.forename: Sônia A L
authors.initials: SA
authors.lastname: Corrêa
authors.forename: Günther K H
authors.initials: GK
authors.lastname: Zupanc
mesh_terms: D000818:Animals; D001370:Axonal Transport / Q000187:drug effects / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology*; D003911:Dextrans; D004557:Electric Organ / Q000502:physiology*; D005456:Fluorescent Dyes; D023702:Gymnotiformes / Q000033:anatomy & histology* / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology* / Q000378:metabolism; D007150:Immunohistochemistry; D008239:Lysine / Q000031:analogs & derivatives*; D009415:Nerve Net / Q000166:cytology* / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology* / Q000378:metabolism; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D012235:Rhodamines; D013788:Thalamus / Q000166:cytology* / Q000378:metabolism
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes; C067661:Fluoro-Ruby; D012235:Rhodamines; C013411:biocytin; D008239:Lysine