The hippocampal lamella hypothesis revisited.
We have re-examined the hippocampal lamellar organization of the CA3-to-CA1 connection. Based on a new technique with electrophysiological quantification of Schaffer collateral density, and a review of recent literature, we conclude that the lamellar organization remains a useful concept for understanding hippocampal connectivity. Using a sheet-like hippocampal preparation, containing the whole CA1 region, we mapped the distribution of Schaffer collaterals by two procedures. First, we recorded the amplitude of the Schaffer compound action potential in various parts of CA1 after stimulation of a point in CA3. Second, we charted the CA1 positions from which we could antidromically excite individual CA3 neurones. Although the Schaffer collaterals radiated from their CA3 cells of origin within a wide, fan-shaped area, covering a large part of the septo-temporal extent of CA1, the amplitude of the compound action potential was largest in a slightly oblique, transverse band across the CA1 towards the subicular region.
Andersen
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P
Department of Neurophysiology, Institute for Basic Medical Sciences, University of Oslo, Pb. 1104 Blindern, 0317, Oslo, Norway. andersen@basalmed.uio.no
Soleng
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AF
Raastad
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M
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001369:Axons / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D009431:Neural Conduction / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D051381:Rats; D011930:Reaction Time / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists