The Journal of Neurophysiology Vol. 77 No. 4 April 1997, pp. 1747-1758
Copyright ©1997 The American Physiological Society

Association Between Dendritic Lamellar Bodies and Complex Spike Synchrony in the Olivocerebellar System

C. I. De Zeeuw^{1, 2}, S.K.E. Koekkoek^{1, 2}, D.R.W. Wylie^{2, 3}, and J. I. Simpson²

¹ Department of Anatomy, Erasmus University Rotterdam, 3000 DR Rotterdam, The Netherlands; ² Department of Physiology and Neuroscience, New York University Medical Center, New York, New York 10016; and ³ Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2EQ, Canada

De Zeeuw, C. I., S.K.E. Koekkoek, D.R.W. Wylie, and J. I. Simpson. Association between dendritic lamellar bodies and complex spike synchrony in the olivocerebellar system. J. Neurophysiol. 77: 1747-1758, 1997. Dendritic lamellar bodies have been reported to be associated with dendrodendritic gap junctions. In the present study we investigated this association at both the morphological and electrophysiological level in the olivocerebellar system. Because cerebellar GABAergic terminals are apposed to olivary dendrites coupled by gap junctions, and because lesions of cerebellar nuclei influence the coupling between neurons in the inferior olive, we postulated that if lamellar bodies and gap junctions are related, then the densities of both structures will change together when the cerebellar input is removed. Lesions of the cerebellar nuclei in rats and rabbits resulted in a reduction of the density of lamellar bodies, the number of lamellae per lamellar body, and the density of gap junctions in the inferior olive, whereas the number of olivary neurons was not significantly reduced. The association between lamellar bodies and electrotonic coupling was evaluated electrophysiologically in alert rabbits by comparing the occurrence of complex spike synchrony in different Purkinje cell zones of the flocculus that receive their climbing fibers from olivary subnuclei with different densities of lamellar bodies. The complex spike synchrony of Purkinje cell pairs, that receive their climbing fibers from an olivary subnucleus with a high density of lamellar bodies, was significantly higher than that of Purkinje cells, that receive their climbing fibers from a subnucleus with a low density of lamellar bodies. To investigate whether the complex spike synchrony is related to a possible synchrony between simple spikes, we recorded simultaneously the complex spike and simple spike responses of Purkinje cell pairs during natural visual stimulation. Synchronous simple spike responses did occur, and this synchrony tended to increase as the synchrony between the complex spikes increased. This relation raises the possibility that synchronously activated climbing fibers evoke their effects in part via the simple spike response of Purkinje cells. The present results indicate that dendritic lamellar bodies and dendrodendritic gap junctions can be downregulated concomitantly, and that the density of lamellar bodies in different olivary subdivisions is correlated with the degree of synchrony of their climbing fiber activity. Therefore these data support the hypothesis that dendritic lamellar bodies can be associated with dendrodendritic gap junctions. Considering that the density of dedritic lamellar bodies in the inferior olive is higher than in any other area of the brain, this conclusion implies that electrotonic coupling is important for the function of the olivocerebellar system.

This article has been cited by other articles:

				J. F. Medina and S. G. Lisberger Variation, Signal, and Noise in Cerebellar Sensory-Motor Processing for Smooth-Pursuit Eye Movements J. Neurosci., June 20, 2007; 27(25): 6832 - 6842. [Abstract] [Full Text] [PDF]

				S.-L. Shin and E. De Schutter Dynamic Synchronization of Purkinje Cell Simple Spikes J Neurophysiol, December 1, 2006; 96(6): 3485 - 3491. [Abstract] [Full Text] [PDF]

				F. J. Urbano, J. I. Simpson, and R. R. Llinas Somatomotor and oculomotor inferior olivary neurons have distinct electrophysiological phenotypes PNAS, October 31, 2006; 103(44): 16550 - 16555. [Abstract] [Full Text] [PDF]

				E. J. Lang, R. Llinas, and I. Sugihara Isochrony in the olivocerebellar system underlies complex spike synchrony J. Physiol., May 15, 2006; 573(1): 277 - 279. [Full Text] [PDF]

				T. A. Blenkinsop and E. J. Lang Block of Inferior Olive Gap Junctional Coupling Decreases Purkinje Cell Complex Spike Synchrony and Rhythmicity J. Neurosci., February 8, 2006; 26(6): 1739 - 1748. [Abstract] [Full Text] [PDF]

				E. J. Lang GABAergic and Glutamatergic Modulation of Spontaneous and Motor-Cortex-Evoked Complex Spike Activity J Neurophysiol, April 1, 2002; 87(4): 1993 - 2008. [Abstract] [Full Text] [PDF]

				M. P. Arts, C. I. De Zeeuw, J. Lips, E. Rosbak, and J. I. Simpson Effects of Nucleus Prepositus Hypoglossi Lesions on Visual Climbing Fiber Activity in the Rabbit Flocculus J Neurophysiol, November 1, 2000; 84(5): 2552 - 2563. [Abstract] [Full Text] [PDF]

				Y. Kobayashi, K. Kawano, A. Takemura, Y. Inoue, T. Kitama, H. Gomi, and M. Kawato Temporal Firing Patterns of Purkinje Cells in the Cerebellar Ventral Paraflocculus During Ocular Following Responses in Monkeys II. Complex Spikes J Neurophysiol, August 1, 1998; 80(2): 832 - 848. [Abstract] [Full Text] [PDF]