Abstract
Feedback inhibition is generally believed to be a ubiquitous feature of brain circuitry, but few specific instances have been documented. An example in cats is the supposed feedback circuit involving relay cells of the lateral geniculate nucleus and cells of the perigeniculate nucleus (a part of the thalamic reticular nucleus): geniculate relay cells innervate the perigeniculate nucleus, which, in turn, provides an inhibitory, GABAergic projection back to the lateral geniculate nucleus. However, feedback inhibition at the single-cell level requires that a given perigeniculate cell project back onto the same geniculate relay cell that innervates it. We probed for this in an in vitro slice preparation of the cat's lateral geniculate nucleus. We evoked a single action potential in a geniculate cell via a brief, depolarizing pulse delivered through an intracellular recording electrode and looked for any evoked hyperpolarizations. For 6 of the 36 geniculate cells tested, we observed a long-lasting hyperpolarization after the action potential, and much of this was eliminated by application of bicuculline, suggesting synaptically activated inhibitory postsynaptic potentials. We interpreted this to be clear evidence that a given neuron may inhibit itself via circuitry mediating feedback inhibition in the cat's lateral geniculate nucleus.
Similar content being viewed by others
References
Aghajanian GK, Rasmussen K (1989) Intracellular studies in the facial nucleus illustrating a simple new methods for obtaining viable motoneurons in adult rat brain slices. Synapse 3:331–338
Bloomfield SA, Sherman SM (1988) Postsynaptic potentials recorded in neurons of the cat's lateral geniculate nucleus following electrical stimulation of the optic chiasm. J Neurophysiol 60:1924–1945
Burke W, Cole AM (1978) Extraretinal influence on the lateral geniculate nucleus. Rev Physiol Biochem Pharmacol 80:105–166
Burke W, Sefton AJ (1966) Inhibitory mechanisms in lateral geniculate nucleus of rat. J Physiol (Lond) 187:231–246
Crunelli V, Leresche N (1991) A role for GABAB receptors in excitation and inhibition of thalamocortical cells. Trends Neurosci 14:16–21
Crunelli V, Haby M, Jassik-Gerschenfeld D, Leresche N, Pirchio M (1988) C1-- and K+-dependent inhibitory postsynaptic potentials evoked by interneurones of the rat lateral geniculate nucleus. J Physiol (Lond) 399:153–176
Friedlander MJ, Lin C-S, Stanford LR, Sherman SM (1981) Morphology of functionally identified neurons in the lateral geniculate nucleus of the cat. J Neurophysiol 46:80–129
Jahnsen H, Llinás R (1984a) Electrophysiological properties of guinea-pig thalamic neurones: an in vitro study. J Physiol (Lond) 349:205–226
Jahnsen H, Llinás R (1984 b) Ionic basis for the electroresponsiveness and oscillatory properties of guinea-pig thalamic neurones in vitro. J Physiol (Lond) 349:227–247
Lindström S (1982) Synaptic organization of inhibitory pathways to principal cells in the lateral geniculate nucleus of the cat. Brain Res 234:447–453
Scharfman HE, Lu S-M, Guido W, Adams PR, Sherman SM (1990) N-methyl-d-aspartate (NMDA) receptors contribute to excitatory postsynaptic potentials of cat lateral geniculate neurons recorded in thalamic slices. Proc Natl Acad Sci USA 87:4548–4552
Sherman SM (1993) Dynamic gating of retinal transmission to the visual cortex by the lateral geniculate nucleus. In: Minciacchi D, Molinari M, Macchi G, Jones EG (eds) Thalamic networks for relay and modulation. Pergamon, Oxford, pp 61–79
Sherman SM, Koch C (1986) The control of retinogeniculate transmission in the mammalian lateral geniculate nucleus. Exp Brain Res 63:1–20
Sherman SM, Koch C (1990) Thalamus. In: Shepherd GM (eds) The synaptic organization of the brain, 3rd edn. Oxford University Press, New York, pp 246–278
Singer W (1977) Control of thalamic transmission by corticofugal and ascending reticular pathways in the visual system. Physiol Rev 57:386–420
Soltesz I, Lightowler S, Leresche N, Crunelli V (1989) On the properties and origin of the GABAB inhibitory postsynaptic potential recorded in morphologically identified projection cells of the cat dorsal lateral geniculate nucleus. Neuroscience 33:23–33
Steriade M, Llinás R (1988) The functional states of the thalamus and the associated neuronal interplay. Physiol Rev 68:649–742
Uhlrich DJ, Cucchiaro JB, Humphrey AL, Sherman SM (1991) Morphology and axonal projection patterns of individual neurons in the cat perigeniculate nucleus. J Neurophysiol 65:1528–1541
Author information
Authors and Affiliations
Additional information
Shanghai Brain Research Institute, Shanghai, People's Republic of China 200031
Rights and permissions
About this article
Cite this article
Lo, F.S., Murray Sherman, S. Feedback inhibition in the cat's lateral geniculate nucleus. Exp Brain Res 100, 365–368 (1994). https://doi.org/10.1007/BF00227207
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00227207