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Computational Intelligence and Neuroscience
Volume 2010, Article ID 340541, 10 pages
http://dx.doi.org/10.1155/2010/340541
Research Article

Stability of Neural Firing in the Trigeminal Nuclei under Mechanical Whisker Stimulation

1Departamento de Matemática Aplicada, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
2Radiophysics and Nonlinear Dynamics Chair, Physics Department, Saratov State University, Astrakhanskaya Str. 83, Saratov 410026, Russia
3Neurocomputing and Neurorobotics Group, Universidad Complutense de Madrid, Avenida Arcos de Jalón s/n, 28037 Madrid, Spain

Received 27 February 2009; Revised 22 June 2009; Accepted 12 October 2009

Academic Editor: Rodrigo Quian Quiroga

Copyright © 2010 Valeri A. Makarov et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Sensory information handling is an essentially nonstationary process even under a periodic stimulation. We show how the time evolution of ridges in the wavelet spectrum of spike trains can be used for quantification of the dynamical stability of the neuronal responses to a stimulus. We employ this method to study neuronal responses in trigeminal nuclei of the rat provoked by tactile whisker stimulation. Neurons from principalis (Pr5) and interpolaris (Sp5i) show the maximal stability at the intermediate (50 ms) stimulus duration, whereas Sp5o cells “prefer” shorter (10 ms) stimulation. We also show that neurons in all three nuclei can perform as stimulus frequency filters. The response stability of about 33% of cells exhibits low-pass frequency dynamics. About 57% of cells have band-pass dynamics with the optimal frequency at 5 Hz for Pr5 and Sp5i, and 4 Hz for Sp5o, and the remaining 10% show no prominent dependence on the stimulus frequency. This suggests that the neural coding scheme in trigeminal nuclei is not fixed, but instead it adapts to the stimulus characteristics.