Journal of Neurophysiology, Vol 65, Issue 6 1528-1541, Copyright © 1991 by APS

ARTICLES

Morphology and axonal projection patterns of individual neurons in the cat perigeniculate nucleus

D. J. Uhlrich, J. B. Cucchiaro, A. L. Humphrey and S. M. Sherman
Department of Neurobiology, State University of New York, Stony Brook 11794-5230.

1. The lateral geniculate nucleus is the primary thalamic relay through which retinal signals pass en route to cortex. This relay is gated and can be suppressed by activity among local inhibitory neurons that use gamma-aminobutyric acid (GABA) as a neurotransmitter. In the cat, a major source of this GABAergic inhibition seems to arise from cells of the perigeniculate nucleus, which lies just dorsal to the A-laminae of the lateral geniculate nucleus. However, the morphological characteristics of perigeniculate cells, and particularly the projection patterns of their axons, have never been fully characterized. We thus examined the morphology of these cells: individually by intracellular injection of horseradish peroxidase (HRP) and en masse with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHAL). 2. We recorded from 12 perigeniculate cells that we impaled and successfully labeled with HRP. These cells exhibited response properties generally consistent with those described previously. They had long response latencies to stimulation of the optic chiasm and relatively large, often diffuse, receptive fields. The visually evoked responses of most of the cells were dominated by one eye. Compared with cells of the lateral geniculate nucleus, perigeniculate cells had large somata (517 +/- 136 microns 2 in cross-sectional area, mean +/- SD), which were fusiform or multipolar in shape, and dendritic arbors that extended a considerable distance (1,095 +/- 167 microns) parallel to the border between the perigeniculate and lateral geniculate nuclei. Terminal arbors of some dendrites were quite complex and beaded. 3. The axons of six perigeniculate cells were labeled sufficiently well to trace and reconstruct over a considerable distance. Each of these axons formed branches that descended to innervate the lateral geniculate nucleus, and this geniculate innervation was exclusively limited to the A-laminae. Terminal boutons within the A-laminae were nearly all en passant, which gave the axons a beaded appearance. Furthermore, branches of five of these six axons provided local innervation of the perigeniculate nucleus, generally within each labeled cell's own dendritic arbor. Three of the cells also exhibited an axon branch that extended medially and caudally away from the soma, but we were unable to trace these axon branches to their targets. 4. Within the lateral geniculate nucleus, each arbor of perigeniculate axons derived from two main components. One was a narrow, sparse medial component that innervated laminae A and A1.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				L. Sirovich Populations of Tightly Coupled Neurons: The RGC/LGN System Neural Comput., May 1, 2008; 20(5): 1179 - 1210. [Abstract] [Full Text] [PDF]

				C. Deleuze and J. R. Huguenard Distinct Electrical and Chemical Connectivity Maps in the Thalamic Reticular Nucleus: Potential Roles in Synchronization and Sensation. J. Neurosci., August 15, 2006; 26(33): 8633 - 8645. [Abstract] [Full Text] [PDF]

				K. L. Blethyn, S. W. Hughes, T. I. Toth, D. W. Cope, and V. Crunelli Neuronal Basis of the Slow (<1 Hz) Oscillation in Neurons of the Nucleus Reticularis Thalami In Vitro J. Neurosci., March 1, 2006; 26(9): 2474 - 2486. [Abstract] [Full Text] [PDF]

				V. Bonin, V. Mante, and M. Carandini The Suppressive Field of Neurons in Lateral Geniculate Nucleus J. Neurosci., November 23, 2005; 25(47): 10844 - 10856. [Abstract] [Full Text] [PDF]

				Y.-W. Lam and S. M. Sherman Mapping by Laser Photostimulation of Connections Between the Thalamic Reticular and Ventral Posterior Lateral Nuclei in the Rat J Neurophysiol, October 1, 2005; 94(4): 2472 - 2483. [Abstract] [Full Text] [PDF]

				C. Broberger and D. A. McCormick Excitatory Effects of Thyrotropin-Releasing Hormone in the Thalamus J. Neurosci., February 16, 2005; 25(7): 1664 - 1673. [Abstract] [Full Text] [PDF]

				P. Lavallee and M. Deschenes Dendroarchitecture and Lateral Inhibition in Thalamic Barreloids J. Neurosci., July 7, 2004; 24(27): 6098 - 6105. [Abstract] [Full Text] [PDF]

				N. Higo, T. Oishi, A. Yamashita, K. Matsuda, and M. Hayashi Expression of GAP-43 and SCG10 mRNAs in Lateral Geniculate Nucleus of Normal and Monocularly Deprived Macaque Monkeys J. Neurosci., August 15, 2000; 20(16): 6030 - 6038. [Abstract] [Full Text] [PDF]

				J. A. Hartings, S. Temereanca, and D. J. Simons High Responsiveness and Direction Sensitivity of Neurons in the Rat Thalamic Reticular Nucleus to Vibrissa Deflections J Neurophysiol, May 1, 2000; 83(5): 2791 - 2801. [Abstract] [Full Text] [PDF]

				U. Kim and D. A. McCormick The Functional Influence of Burst and Tonic Firing Mode on Synaptic Interactions in the Thalamus J. Neurosci., November 15, 1998; 18(22): 9500 - 9516. [Abstract] [Full Text] [PDF]

				U. Kim and D. A. Mccormick Functional and Ionic Properties of a Slow Afterhyperpolarization in Ferret Perigeniculate Neurons In Vitro J Neurophysiol, September 1, 1998; 80(3): 1222 - 1235. [Abstract] [Full Text] [PDF]

				M. V. Sanchez-Vives, T. Bal, and D. A. McCormick Inhibitory Interactions between Perigeniculate GABAergic Neurons J. Neurosci., November 15, 1997; 17(22): 8894 - 8908. [Abstract] [Full Text] [PDF]

				U. Kim, M. V. Sanchez-Vives, and D. A. McCormick Functional Dynamics of GABAergic Inhibition in the Thalamus Science, October 3, 1997; 278(5335): 130 - 134. [Abstract] [Full Text]

				C. L. Cox, J. R. Huguenard, and D. A. Prince Nucleus reticularis neurons mediate diverse inhibitory effects in thalamus PNAS, August 5, 1997; 94(16): 8854 - 8859. [Abstract] [Full Text] [PDF]

				D. Pinault, Y. Smith, and M. Deschenes Dendrodendritic and Axoaxonic Synapses in the Thalamic Reticular Nucleus of the Adult Rat J. Neurosci., May 1, 1997; 17(9): 3215 - 3233. [Abstract] [Full Text] [PDF]

				M. V. Sanchez-Vives, T. Bal, U. Kim, M. von Krosigk, and D. A. McCormick Are the Interlaminar Zones of the Ferret Dorsal Lateral Geniculate Nucleus Actually Part of the Perigeniculate Nucleus? J. Neurosci., October 1, 1996; 16(19): 5923 - 5941. [Abstract] [Full Text] [PDF]