Summary
Hippocampo-septal fibers, labeled by anterograde degeneration following transection of the fimbriafornix, were found to establish asymmetric synaptic contacts on spines of identified (Golgi-impregnated and gold-toned) multipolar neurons in the dorsolateral nucleus of the septal region. Evidence from the literature suggests that these cells project onto medial septal neurons, which in turn project back to the hippocampal formation. The present study thus establishes a missing link in this circuitry, viz., one group of target cells of the hippocampal fibers.
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Alonso JR, Frotscher M (1989) The organization of the septal region in the rat brain: a Golgi/EM study of lateral septal neurons. J Comp Neurol (in press)
Amaral DG, Kurz J (1985) An analysis of the origins of the cholinergic and non-cholinergic septal projections to the hippocampal formation of the rat. J Comp Neurol 240:37–59
Bialowas J, Frotscher M (1987) Choline acetyltransferase-immunoreactive neurons and terminals in the rat septal complex: a combined light and electron microscopic study. J Comp Neurol 259:298–307
DeFrance JF, Shimono T, Kitai ST (1971) Anatomical distribution of the hippocampal fibers afferent to the lateral septal nucleus. Brain Res 34:176–180
Fairén A, Peters A, Saldanha J (1977) A new procedure for examining Golgi impregnated neurons by light and electron microscopy. J Neurocytol 6:311–337
Freund TF, Antal M (1988) GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus. Naure 366:170–173
Frotscher M (1985) Mossy fibres form synapses with identified pyramidal basket cells in the CA3 region of the guinea-pig hippocampus: a combined Golgi-electron microscope study. J Neurocytol 14:245–259
Frotscher M, Zimmer J (1986) Intracerebral transplants of the rat fascia dentata: a Golgi/electron microscope study of dentate granule cells. J Comp Neurol 246:181–190
Gall C, Moore RY (1984) Distribution of enkephalin, substance P, tyrosine hydroxylase, and 5-hydroxytryptamine immunoreactivity in the septal region of the rat. J Comp Neurol 225:212–227
Leranth C, Frotscher M (1989) The organization of the septal region in the rat brain: cholinergic-GABAergic interconnections and the termination of hippocampo-septal fibers. J Comp Neurol (in press)
Raisman G (1966) The connexions of the septum. Brain 89:317–348
Raisman G (1969) Neuronal plasticity in the septal nuclei of the adult rat. Brain Res 14:25–48
Raisman G, Field PM (1973) A quantitative investigation of the development of collateral reinnervation after partial deafferentation of the septal nuclei. Brain Res 50:241–264
Stevens DR, Cotman CW (1986) Excitatory amino acid antagonists depress transmission in hippocampal projections to the lateral septum. Brain Res 382:437–440
Swanson LW (1978) The anatomical organization of septo-hippocampal projections. In: Gray A (ed) Functions of the septohippocampal system. Ciba Foundation Symposium Series, Vol. 58, Elsevier, Amsterdam, pp 25–48
Swanson LW, Cowan WM (1979) The connections of the septal region in the rat. J Comp Neurol 186:621–656
Swanson LW, Sawchenko PE, Cowan WM (1980) Evidence that the commissural, associational and septal projections of the regio inferior of the hippocampus arise from the same neurons. Brain Res 197:207–212
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J.R. Alonso is on leave of absence from the Department of Cytology and Histology, Faculty of Biology, University of Salamanca, 37008 Salamanca, Spain
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Alonso, J.R., Frotscher, M. Hippocampo-septal fibers terminate on identified spiny neurons in the lateral septum: A combined Golgi/electron-microscopic and degeneration study in the rat. Cell Tissue Res. 258, 243–246 (1989). https://doi.org/10.1007/BF00239444
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DOI: https://doi.org/10.1007/BF00239444