Ciencia y Tecnologías Físicas >
Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC) >
(IFISC) Artículos >
Closed Access item Stochastic Resonance in the Motor System: Effects of Noise on the Monosynaptic Reflex Pathway of the Cat Spinal Cord
Mirasso, Claudio R.
|Keywords:||Stochastic resonance, Noise (statistical physics), Nonlinear dynamical systems, Neuroscience, Biological/Medical Physics|
|Publisher:||American Physiological Society|
|Citation:||Journal of Neurophysiology 97, 4007-4016 (2007)|
|Abstract:||In sensory systems the presence of a particular non-zero level of noise may significantly
enhance the ability of an individual to detect weak sensory stimuli through a phenomenon known as stochastic resonance (SR). The aim of this study was to demonstrate if such phenomenon is also exhibited by the motor system; in particular, in the Ia-motoneuron synapse of the cat spinal cord. Monosynaptic reflexes elicited by periodic electrical stimulation to the medial gastrocnemius nerve were recorded in the L7 ventral root (or in single motoneurons) of decerebrated cats. Random stretches (mechanical noise) were applied to the lateral gastrocnemius plus soleus muscle by means of a closed-loop mechanical stimulator-transducer. In all cats we observed the SR phenomenon. The amplitude of the monosynaptic reflexes (or number of action
potentials recorded in the motoneurons) evoked by the weak electrical stimuli applied to the medial gastrocnemius nerve were an inverted U-like function of the mechanical noise applied to the lateral gastrocnemius plus soleus muscle. A significant maximum value in the amplitude of the monosynaptic responses was reached with a particular noise amplitude value. Numerical simulations on a model of the monosynaptic reflex
pathway qualitatively reproduce this stochastic resonance behavior. We conclude that the monosynaptic reflex response elicited by Ia afferents is optimized by the noisy stretching of a synergistic muscle. Our study provides the first direct demonstration that the motor system, and not only the sensory systems, exhibits the SR phenomenon.|
|Description:||10 pages, 4 figures.-- PMID: 17428901 [PubMed].|
|Publisher version (URL):||http://dx.doi.org/10.1152/jn.01164.2006|
|Appears in Collections:||(IFISC) Artículos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.