Electrical stimulation of chemical blockade of vestibular nuclei can serve as the unconditioned stimulus in the conditioned taste aversion paradigm.

Nausea of vestibular origin can be used instead of poisoning in the conditioned taste aversion (CTA) paradigm. In an attempt to establish the forms of vestibular stimulation best suited for inducing CTA in rats, effectiveness of 2 h rotation (Exp. 1) was compared with tonal asymmetry elicited by unilateral microinjection of 5.0 microliters of 25% KCl into the vestibular complex (Exp. 2), by unilateral electrical stimulation of vestibular nuclei (100 Hz, 1 ms, 100-200 microA, 15 min--Exp. 3) or by 10 min polarization of labyrinth through electrodes inserted in the external auditory meati (Exp. 4). Nystagmus, deviation of the head and leaning towards the blocked and away from the stimulated side were typical symptoms. When the above stimuli were applied within 10 min after saccharin drinking, galvanic stimulation was ineffective, but electrical stimulation or chemical blockade of vestibular nuclei elicited marked CTA to saccharin, considerably stronger than CTA induced by rotation. It is concluded that direct interference with the activity of vestibular nuclei elicits CTA more effectively than the stimulation of the labyrinth and is, therefore, well suited for the analytical research into the mechanisms of CTA.