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

This Article Full Text Full Text (PDF) All Versions of this Article: 90/4/2240    most recent 00402.2003v1 Alert me when this article is cited 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 Pastor, A. M. Articles by González-Forero, D. Search for Related Content PubMed PubMed Citation Articles by Pastor, A. M. Articles by González-Forero, D.

Recruitment Order of Cat Abducens Motoneurons and Internuclear Neurons

Departamento de Fisiología y Zoología, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain

Submitted 22 April 2003; accepted in final form 6 June 2003

Abducens neurons undergo a dose-dependent synaptic blockade (either disinhibition or complete blockade) when tetanus neurotoxin (TeNT) is injected into the lateral rectus muscle at either a low (0.5) or a high dose (5 ng/kg). We studied the firing pattern and recruitment order in abducens neurons both in control and after TeNT injection. The eye position threshold for recruitment of control abducens neurons was exponentially related to the eye position and velocity sensitivities. We also found a constancy of recruitment threshold for different eye movement modalities (spontaneous, optokinetic, and vestibular). Exponential relationships were found, as well, for eye velocity sensitivity during saccades and for position and velocity sensitivities during the vestibulo-ocular reflex. Likewise, inverse relationships were found between recruitment threshold or position sensitivity with the antidromic latency in control abducens neurons. These relationships, however, did not apply following TeNT treatment. Neuronal firing after TeNT appeared either disinhibited (low dose) or depressed (high dose), but the relationships between neuronal sensitivities and recruitment still applied. However, the pattern of recruitment shifted toward the treated side as more inputs were blocked by the low- and high-dose treatments, respectively. Nonetheless, although the recruitment-to-sensitivity relationships persisted under the TeNT synaptic blockade, we conclude that synaptic inputs are determinant for establishing the recruitment threshold and recruitment spacing of abducens motoneurons and internuclear neurons.

This article has been cited by other articles:

				M. S. Jones and M. Ariel Morphology, Intrinsic Membrane Properties, and Rotation-Evoked Responses of Trochlear Motoneurons in the Turtle J Neurophysiol, March 1, 2008; 99(3): 1187 - 1200. [Abstract] [Full Text] [PDF]

				D. Gonzalez-Forero, S. Morcuende, F. J. Alvarez, R. R. de la Cruz, and A. M. Pastor Transynaptic effects of tetanus neurotoxin in the oculomotor system Brain, September 1, 2005; 128(9): 2175 - 2188. [Abstract] [Full Text] [PDF]

				D. Gonzalez-Forero, F. Portillo, C. R. Sunico, and B. Moreno-Lopez Nerve injury reduces responses of hypoglossal motoneurones to baseline and chemoreceptor-modulated inspiratory drive in the adult rat J. Physiol., June 15, 2004; 557(3): 991 - 1011. [Abstract] [Full Text] [PDF]