SLEEPUltradian rhythmic neuronal oscillation in the intergeniculate leafletLewandowski, Marian H.1,2; Błasiak, Tomasz1; Domosławski, Jacek1; Wołkowska, Anna1Author Information 1Department of Animal Physiology, Institute of Zoology, Jagiellonian University, R. Ingardena St. 6, 30-060 Cracow, Poland 2Corresponding Author: Marian H. Lewandowski Received 21 October 1999; accepted 14 November 1999 Acknowledgements: This work was supported by the Committee for Scientific Research, KBN grant no PB418/PO4/96/10 (awarded to M.H. Lewandowski). We dedicate this work to Professor Józef Surowiak on the occasion of his 75th birthday. NeuroReport: February 7, 2000 - Volume 11 - Issue 2 - p 317-321 Buy Abstract Our paper is the first to describe ultradian rhythmic neuronal oscillation in the intergeniculate leaflet (IGL) of the rat. We recorded a multiple-unit neuronal activity (MUA) from dorsal to ventral parts of the lateral geniculate nucleus (LGN) in anaesthetized rats. In all the subdivisions of the lateral geniculate complex we observed spontaneous irregular firing rates of cells. However only at the anatomical localisation of the IGL, after the light was on, those responses exhibited burst firing with a constant interburst interval, which lasted several hours until the light was off. The duration of that rhythmic oscillation obtained by means of Fourier's analysis was ∼124 s. To date we have not had sufficient data to discuss possible mechanisms of this neuronal rhythmicity. We can only conclude that light is the most important stimulus not only for suprachiasmatic nuclei (SCN), but also for the IGL. On the other hand, we can neither exclude nor confirm that in order to evoke ultradian rhythmical oscillation in the IGL, in addition to light also non-photic information is necessary. © 2000 Lippincott Williams & Wilkins, Inc.