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: 98/4/2074    most recent 00210.2007v1 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 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 Google Scholar Google Scholar Articles by Lepora, N. F. Articles by Dean, P. Search for Related Content PubMed PubMed Citation Articles by Lepora, N. F. Articles by Dean, P.

Evidence From Retractor Bulbi EMG for Linearized Motor Control of Conditioned Nictitating Membrane Responses

¹Department of Psychology, University of Sheffield, Sheffield, United Kingdom; ²School of Psychology, University of Birmingham, Edgbaston, Birmingham; and ³Department of Anatomy and Developmental Biology, University College London, London, United Kingdom; and ⁴Department of Neurobiology and Behavior, State University of New York, Stony Brook, New York

Submitted 27 February 2007; accepted in final form 3 July 2007

Classical conditioning of nictitating membrane (NM) responses in rabbits is a robust model learning system, and experimental evidence indicates that conditioned responses (CRs) are controlled by the cerebellum. It is unknown whether cerebellar control signals deal directly with the complex nonlinearities of the plant (blink-related muscles and peripheral tissues) or whether the plant is linearized to ensure a simple relation between cerebellar neuronal firing and CR profile. To study this question, the retractor bulbi muscle EMG was recorded with implanted electrodes during NM conditioning. Pooled activity in accessory abducens motoneurons was estimated from spike trains extracted from the EMG traces, and its temporal profile was found to have an approximately Gaussian shape with peak amplitude linearly related to CR amplitude. The relation between motoneuron activity and CR profiles was accurately fitted by a first-order linear filter, with each spike input producing an exponentially decaying impulse response with time constant of order 0.1 s. Application of this first-order plant model to CR data from other laboratories suggested that, in these cases also, motoneuron activity had a Gaussian profile, with time-of-peak close to unconditioned stimulus (US) onset and SD proportional to the interval between conditioned stimulus and US onsets. These results suggest that for conditioned NM responses the cerebellum is presented with a simplified "virtual" plant that is a linearized version of the underlying nonlinear biological system. Analysis of a detailed plant model suggests that one method for linearising the plant would be appropriate recruitment of motor units.

This article has been cited by other articles:

				N. F. Lepora, J. Porrill, C. H. Yeo, C. Evinger, and P. Dean Recruitment in Retractor Bulbi Muscle During Eyeblink Conditioning: EMG Analysis and Common-Drive Model J Neurophysiol, October 1, 2009; 102(4): 2498 - 2513. [Abstract] [Full Text] [PDF]

				S. R. Anderson, J. Porrill, S. Sklavos, N. J. Gandhi, D. L. Sparks, and P. Dean Dynamics of Primate Oculomotor Plant Revealed by Effects of Abducens Microstimulation J Neurophysiol, June 1, 2009; 101(6): 2907 - 2923. [Abstract] [Full Text] [PDF]