A case of visuo-auditory sensory substitution in rats.

Sensory substitution refers to a process whereby an agent, by means of a removable specialized instrumentation, becomes capable of exploiting an available sensory modality in order to perceive properties of the environment which are normally accessible by means of a different modality. We describe a situation of visual-auditory sensory substitution in the rat. Rats were placed in complete darkness, and trained to follow a virtual path whose position was signalled by a sound activated by a video-tracking device.

Fear-like behavioral responses in mice in different odorant environments: Trigeminal versus olfactory mediation under low doses.

Odors can have repulsive effects on rodents based on two complementary adaptive behaviors: the avoidance of predator odors (potentially dangerous) and the avoidance of trigeminal stimulants (potentially noxious). The present study aimed to compare the behavioral effects on mice of odors according to their trigeminal properties and ecological significance. We used three different odors: 2,4,5-trimethylthiazoline (TMT: a fox feces odor frequently used to elicit fear-induced behaviors), toluene (a strong stimulant of the trigeminal system) and phenyl ethyl alcohol (PEA: a selective stimulant of the olfactory system).

Comparative Fear-Related Behaviors to Predator Odors (TMT and Natural Fox Feces) before and after Intranasal ZnSO(4) Treatment in Mice.

The possibility that synthetic 2,4,5-trimethylthiazoline (TMT), frequently used to induce unconditioned fear in rodents, could be more a pungent odor activating intranasal trigeminal nerve fibers rather than a predator odor index is currently discussed. In order to explore this question, the present study compared fear-related behaviors to predator odors (synthetic 10% TMT and natural fox feces) and toluene (as an irritant compound without ecological significance) before and after intranasal ZnSO(4) perfusion which is known to provoke transient anosmia. Results show that natural fox feces could be consider as a pure olfactory (CN I) nerve stimulant while 10% TMT appeared to be a mixed olfactory (CN I) and trigeminal (CN V) nerves stimulant with a great olfactory power and a low trigeminal power.

Effects of CO2 inhalation exposure on mice vomeronasal epithelium.

Nasal epitheliums are the first sites of the respiratory tract in contact with the external environment and may therefore be susceptible to damage from exposure to many toxic volatile substances (i.e., volatile organic components, vapors, and gases).

Comparative behavioral effects between synthetic 2,4,5-trimethylthiazoline (TMT) and the odor of natural fox (Vulpes vulpes) feces in mice.

Synthetic 2,4,5-trimethylthiazoline (TMT)--a component of red fox (Vulpes vulpes) feces--is frequently used to induce unconditioned fear in rodents. Surprisingly, direct comparison between TMT and natural fox feces odor is almost nonexistent. In this study, Experiment 1 compared the avoidance in relation to TMT concentration, natural fox feces, and gender of fox and mice.