Physiological identification and analysis of dentate granule cell responses to stimulation of the medial and lateral perforant pathways in the rat

B. L. McNaughton, C. A. Barnes

Research output: Contribution to journalArticlepeer-review

216 Scopus citations

Abstract

Stimulation of the dorsomedial or ventrolateral perforant pathways resulted in quantitatively different extracellularly recorded EPSPs in the fascia dentata of the rat. The two potential differed in latency to peak and in width at half amplitude in a manner consistent with the different locus of termination of the two pathways on the granule cell dendrites. Both potentials were able to follow brief stimulus trains of 100 Hz, which suggests that they are monosynaptic. Medially elicited responses had their peak negativity approximately 100 to 180 μm deeper in the molecular layer than laterally elicited responses. Stimulation at short intervals along a dorsomedial to ventrolateral track in the angular bundle yielded a step function rather than a continuum of EPSP peak latency and half‐width, in agreement with Hjorth‐Simonsen's ('72) evidence for the separateness of the two pathways. Both pathways were able to induce granule cell discharge. Laterally elicited spikes, however, were delayed. Stimulation at intermediate locations frequently elicited double spikes from granule cell population. Population spikes elicited by either pathway were inhibited for as long as 100 msec after a single discharge. Both pathways showed facilitation with double stimuli at short intervals, and both showed post‐tetanic potentiation lasting at least 30 minutes. Under conditins where it could be shown that the two pathways at least partially converged onto the same granule cells, the response of one pathway did not increase when long lasting potentiation was induced on the other.

Original languageEnglish (US)
Pages (from-to)439-453
Number of pages15
JournalJournal of Comparative Neurology
Volume175
Issue number4
DOIs
StatePublished - Oct 15 1977
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)

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