Results obtained from our work on phantom auditory perception, using behavioral and electrophysiological methods, strongly suggest that animals are able to perceive phantom auditory sensation and that it is possible to detect this state in animals. The behavioral procedure is based on Pavlovian suppression of trained licking, employing offset of a continuous sensory signal as the conditioned stimulus. Experiments involving more complex auditory and visual stimuli further support our approach. Recent experiments showed that it is possible to induce changes in animal behavior using random visual stimuli,l and these results are in full agreement with previous data obtained using the auditory modality, further confirming the validity of our strategy. Encouraged by these results, expansion of this work is proposed to include hallucinatory-type phantom perception in auditory and visual modalities. This would allow for development of animal models of auditory and visual phantom perception and hallucination, as well as additionally testing our approach by cross-examining this behavioral paradigm by using a drug affecting one sensory modality while performing conditioned training with another. The expectation is that while changes should be observed in the performance of animals when the drug used is expected to evoke sensation from the same modality as used for conditional training, it should be without effect when training is done with external stimuli belonging to a different modality. Accordingly, the proposed work will be divided into three stages: i) refinement of the procedure involving phantom auditory perception in the direction of increasing its sensitivity and widening its generalization; ii) on the basis of results obtained in the first stage, to develop a behavioral model which would allow for detection of drug-induced auditory hallucinations in animals; iii) to develop a behavioral model which would allow for detection of drug-induced visual hallucinations in animals and to use the auditory procedure as a control for visual and vice versa. Therefore, a foundation may be created for future research projects related to basic questions of the relationship between external physical properties of environmental events and internal subjective perception, as well as may have clinical implications by creating animal models for disorders presently outside the realm of experimental work.
