HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free A correction has been published Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Koos, B. J. Articles by Kruger, L. Search for Related Content PubMed PubMed Citation Articles by Koos, B. J. Articles by Kruger, L.

Electrical stimulation of the posteromedial thalamus modulates breathing in unanesthetized fetal sheep

Departments of Obstetrics and Gynecology, and Neurobiology, Nicholas S. Assali Perinatal Research Laboratory, Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, California 90095-1740

Submitted 15 May 2003 ; accepted in final form 5 September 2003

Having previously shown that lesions in the posteromedial group of thalamic nuclei abolish hypoxic inhibition of fetal breathing, we devised this study to identify thalamic loci that depress breathing by focal stimulation of specific sectors of the caudal thalamus and adjacent structures. Multipolar electrode arrays consisting of a series of eight stimulation contacts at 1.25-mm intervals were implanted vertically through guide cannulae into the caudal diencephalon of 12 chronically catheterized fetal sheep (>0.8 term), and central neural tissue was stimulated between adjacent contacts. Each site was stimulated repeatedly with increasing current searching for spatial and stimulus strength parameters for a reliable alteration in respiratory rate. Respiratory period increased when stimulation involved areas of the parafascicular nuclear complex (Pf), which more than doubled the mean period compared with the baseline of 0.90 ± 0.19 s. The change in respiratory period was due to an increase in expiratory time, whereas inspiratory time and breath amplitude were not significantly affected. Breathing period and expiratory time were also increased when the stimulations involved the intralaminar wing surrounding the mediodorsal nucleus, the rostral central gray, zona incerta, and ventral tegmental area. Reductions in respiratory frequency occurred less consistently, with stimulation involving surrounding zones including the sub-Pf, ventromedial nucleus, and ventrobasal nuclear complex. These findings support the hypothesis that a restricted area of the posteromedial thalamus (principally Pf) constitutes part of a neuronal circuitry that modulates respiratory motoneurons.

brain; fetus; hypoxia; respiration

This article has been cited by other articles:

				B. J. Koos, Y. Kawasaki, Y.-H. Kim, and F. Bohorquez Adenosine A2A-receptor blockade abolishes the roll-off respiratory response to hypoxia in awake lambs Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1185 - R1194. [Abstract] [Full Text] [PDF]

				P. M. Macey, M. A. Woo, K. E. Macey, T. G. Keens, M. M. Saeed, J. R. Alger, and R. M. Harper Hypoxia reveals posterior thalamic, cerebellar, midbrain, and limbic deficits in congenital central hypoventilation syndrome J Appl Physiol, March 1, 2005; 98(3): 958 - 969. [Abstract] [Full Text] [PDF]