The design and application of three speaker-based stimulating devices for cutaneous stimulation in anesthetized and awake animals

Those wishing to study neuronal plasticity in sensory systems are confronte d by the need to deliver equivalent stimuli to the organism at time interva ls separated by hours, days or months. This problem is particularly acute i n the somatosensory system where delivering all equivalent stimulus general ly requires a second physical contact with the same point on a geometricall y complex surface. This requirement is difficult to fulfill. We have design ed two stimulators that avoid or minimize the importance of this requiremen t by obviating the need for the stimulator to be at a fixed distance from t he skin. As well, we have redesigned a system for whisker stimulation origi nally proposed by Simons. The first stimulator is appropriate for experimen ts in anesthetized animals; the surface to be stimulated is immersed in wat er warmed to body temperature and the tactile stimulus is generated as an h ydraulic pulse. The second uses a high velocity pulse of air shaped so that it can be transmitted significant distances without attenuation. The redes ign of the Simons' vibrissa stimulator provides larger amplitude displaceme nts and lower controlling voltages more readily generated by equipment norm ally found in laboratories. We also described the design of a chamber for r estricting the awake rat during chronic study and the electrodes used for r ecording and for delivery of drugs in awake animals held in such a chamber. (C) 2000 Elsevier Science B.V. All rights reserved.