UNIT RESPONSIVITY IN VARIOUS HIPPOCAMPAL LAYERS AND DEPRESSIVE EFFECTS OF ETHANOL | Academic Article individual record
abstract

This research was a study, using acutely prepared rabbits, of neuronal responsivity in 7 hippocampal layers to electrical stimulation of the 3 primary input structures (entorhinal cortex, septum, and midbrain reticular formation). For each stimulus/response site, we determined the minimal stimulus intensity required to evoke a threshold response ({less-than or greater-than} X ̄ ± 2 SD of the discharge rate immediately prior to stimulation). For all stimulus/response site combinations, the threshold voltage was low (range of 0.17 to 0.45 volts), and a threshold response was easily obtained (range of 60 to 100% of the trials). The predominant response was excitatory, but depression sometimes occurred (up to 20% incidence). Areas that never showed depression were the hippocampal and dentate molecular layers and the subiculum. The high incidence of low threshold, excitatory responses in all layers to all 3 kinds of input indicates that the hippocampus is very sensitive to diverse inputs and that excitatory input is readily distributed throughout all layers. A second phase of the research was a test of ethanol (0.8 gm/kg) influence on the evoked unit responses. Ethanol elevated threshold for all pairings. Regional differences were clearly established with brainstem reticular formation stimulation, in which threshold after ethanol was elevated more in the hippocampal molecular layer and, to a lesser extent, in the dentate granule cell layer. © 1978.

author list (cited authors)
FOLGER, W. R., & KLEMM, W. R.
publication date
1978
publisher
Elsevier bv Publisher
published in
keywords
  • Depression, Chemical
  • Evoked Potentials
  • Electric Stimulation
  • Hippocampus
  • Rabbits
  • Neurons
  • Animals
  • Ethanol
citation count

6