In vivo recording of postsynaptic potentials and low threshold spikes in W cells of the cat's lateral geniculate nucleus

Exp Brain Res. 1990;81(2):438-42. doi: 10.1007/BF00228138.

Abstract

We obtained good intracellular recording from 5 W cells in the C-laminae of the cat's lateral geniculate nucleus. The recordings were made from an anesthetized and paralyzed in vivo preparation. We found a consistent pattern for the postsynaptic potentials evoked from activation of the optic chiasm: first was an IPSP followed by an EPSP. This is very different from the pattern seen in X and Y cells, for which an EPSP always appears first and is then followed by an IPSP. We interpret the pattern for W cells as follows. The initial IPSP is disynaptic; this involves retinogeniculate conduction over very fast Y axons and a relay through an interneuron. The EPSP is monosynaptic, reflecting retinogeniculate conduction over very slow W axons. A possible implication for this is that activity over the Y pathway may generally inhibit geniculate W cells before these W cells can be excited by their retinal afferents. Finally, we elicited from each of these W cells voltage-dependent, low threshold spikes, which are very similar to those displayed by X and Y cells. These spikes can interrupt normal retinogeniculate transmission, and they are prevented by maintaining relatively depolarized membrane potentials.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cats
  • Electric Stimulation / methods
  • Electrophysiology / methods
  • Evoked Potentials
  • Geniculate Bodies / cytology
  • Geniculate Bodies / physiology*
  • Models, Neurological
  • Optic Chiasm / physiology
  • Synapses / physiology*