Preferences, odor

It was thought previously that there were no inborn odor preferences that these are learned from experience. However, studies at the MoneU Center have indicated that flavors consumed by a mother and transmitted into the milk influence the feeding behavior of her infant. When mothers consume gadic, their infants feed longer than when no gadic is consumed (7). 

Drickamer L.C. and Brown P.L. (1998). Age-related changes in odor preferences by house mice living in semi-natural enclosures. J Chem Ecol 24, 1745-1756. 

Mossman C.A. and Drickamer L.C. (1996). Odor preferences of female house mice (Mus domesticus) in seminatural enclosures. J Comp Psychol 110, 131-138. 

Petrulis A., Peng M. and Johnston R.E. (1999). Effects of vomeronasal organ removal on individual odor discrimination, sex-odor preference, and scent marking by female hamsters. Physiol Behav 66, 73-83. 

Rawleigh J.M., Kemble E.D. and Ostrem J. (1993) Differential effects of prior dominance or subordination experience on conspecific odor preferences in mice. Physiol Behav 54, 35-39. 

Pierce, A.A. and Ferkin, M.H. (2005) Re-feeding and the restoration of odor attractivity, odor preference, and sexual receptivity in food-deprived female meadow voles. Physiol. Behav. 84, 553-561. 

Fig. 23.1 Results of the odor preference test in a Y-maze (A). Female mice carrying lesions in either the MOE (B) or VNO (C) were given a choice between volatile odors derived from an intact or a gonadectomized male...

Woodley, S.K., Cloe, A.L., Waters, P. and Baum, M.J. (2004) Effects of vomeronasal organ removal on olfactory sex discrimination and odor preferences of female ferrets. Chem. Senses 29, 659-669. 

The Role of Early Olfactory Experience in the Development of Adult Odor Preferences in Rodents... 

Abstract Mate recognition is an essential component of successful reproductive behavior, and in rodent species, is primarily guided by the perception of social odors in the environment. Importantly, there is substantial evidence that species or sexual odor preferences may be regulated by early olfactory experience, although considerable variability in the plasticity of these behaviors has been observed. The current chapter summarizes what is known regarding the role of early olfactory experience in the development of adult odor preferences, synthesizing data across species, sex, and behavioral paradigms. 

If adult odor preferences are in fact influenced by early olfactory experience, then chemosensory processing must be functional early in rodent development. Indeed, the chemosensory systems develop very early in rodents (Alberts 1976 Astic and Saucier 1981), and chemosensory processing appears to be functional both prena-tally (Pedersen and Blass 1982 Stickrod, Kimble and Smotherman 1982) and peri-natally, as evidenced by behavioral responses to odors (Devor and Schneider 1974 Gregory and Bishop 1975 Leon and Moltz 1971 Porter and Etscorn 1974). For example, Syrian hamster pups display behavioral preferences for different types of artificial odorants as early as postnatal day 4 (Devor and Schneider 1974). These data suggest that young rodents are able to both process and respond to odors present in their early environment. 

Much of the previous research on the role of early olfactory experience on adult odor preferences has used the approach of cross-fostering young pups to a lactating dam of a different species (D Udine 1983). Thus, a shift in preference toward odor of the foster parent indicates that species-specific odors are learned via the early experience with the foster parent. Several important themes have emerged from this literature that shed light on the degree to which species preference is learned during early life. 

In general, rodents that have been exposed to an artificial odor during early life show an increased attraction to stimulus animals scented with that odor as adults. Increased odor preference following early exposure has been observed in female mice (Mainardi, Marsan and Pasquali 1965) and male rats (Marr and Gardner 1965). In some cases, this odor preference translates into increases in mating efficiency with females of the familiar scent. Specifically, male rats reared with citral-scented dams ejaculate faster when mating with citral-scented females compared to normal-scented females (Fillion and Blass 1986). 

However, some studies report only marginal effects of early odor exposure on adult odor preference. These contradictory findings may be due to differences either in the behavioral measures or species tested. For example, although Moore, Jordan and Wong (1996) observed decreases in ejaculation latencies similar to those observed by Fillion and Blass (1986), the author found no effect of early odor... 

Unlike control females, chemically naive females do not prefer the volatile components of male odors compared to female odors. When these females are allowed contact with the odors, however, they demonstrate robust preferences for the male odors. Critically, initially naive females that receive contact experience with male soiled bedding as adults display sexual odor preferences when subsequently... 

Our laboratory has begun to determine if this phenomenon of experience-dependent attraction to male volatile cues also occurs in female Syrian hamsters, as experiential effects on odor preference may vary according to species. Syrian hamsters provide an ideal model species for studying sexual preference as these behaviors are almost exclusively mediated by chemosensory cues (Johnston 1983). Furthermore, both males and females display robust preferences for opposite-sex volatile odors that are independent of adult sexual experience (Landauer, Banks and Carter 1977 Petrulis and Johnston 1999), suggesting that early olfactory experience may play a critical role in the development of these behaviors. 

Taken together, this body of work demonstrates that adult behavioral responses to social odors are shaped by early olfactory experience. Indeed, heterospecific or artificial odor cues associated with the rearing environment acquire attractive properties that can last into adulthood in many rodent species. Furthermore, early experience with opposite-sex odors appears to be critical for the normal development of appropriate behavioral responses to sexual odors in mice and hamsters. Importantly, the behavioral plasticity observed using these different experimental approaches may all be mediated by a classical conditioning model of olfactory learning. The experience-dependent development of odor preference in rodents therefore provides a powerful model for understanding how the olfactory system recognizes and learns the salience of social odors, a function that is critical for the appropriate expression of reproductive behavior. 

Rangel, S. and Leon, M. (1995) Early odor preference training increases olfactory bulb norepinephrine. Brain Res. Dev. Brain Res. 85, 187-191. 

Solomon, N.G. and Rumbaugh, T. (1997) Odor preferences of weanling and mature male and female pine voles. J. Chem. Ecol. 23, 2133-2143. 

Learning of the parental odor may be important for odor preferences (Jemiolo etah, 1991). Estrous white-footed mice prefer males of intermediate relatedness, or their odors. The levels of reproductive success (i.e. litter size at weaning and offspring weight at weaning) indicated inbreeding depression. Non-estrous females showed no preferences (Keane, 1990). 

Both social and dietary odor preferences may be acquired in utero. Rat pups at 8 hours of age orient more toward the amniotic fluid of their mother than to that of an unrelated female rat. This preference must be acquired prenatally, as Caesarean-born pups also prefer the mother s amniotic fluid. At birth, rats already know the odor of their kin (Hepper, 1987). The vomeronasal organ probably monitors the chemical quality of the intrauterine environment (Pedersen etal., 1983). 

Infants are able to acquire odor preferences on the first day of life. In one experiment, 12 male and 12 female white, healthy, full-term neonates were exposed to the odors of cherry or ginger on a pad taped to the inside of their crib for 24 hours. After this exposure, they were tested for preferences during active sleep (stage II). The behavior was videotaped and the duration of time oriented to each odor measured. Only the female neonates showed a preference for the familiar odor (Balogh and Porter, 1986). Therefore, even on the first day of life, females outperform males, as often described for children and adults (e.g. Yousem etal, 1999). 

Preschool children are reputed to differ from adults in their odor preferences. For instance children aged 3-4 years were as likely to like the odor of amyl acetate (banana) as synthetic sweat or feces odors. By 6 years of age, their preferences resembled adults, liking banana, and disliking sweaty and fecal odors (Stein et al., 1958). At 4-5 years of age, a shift occurs from positive or neutral to negative characterization of odors of sweat, feces, asa foetida, or butyric acid. However, it is increasingly becoming clear that responses by very young children... 

The odor preferences of rat pups aged 3-6 days can be reversed by training. If the initially avoided odor of orange extract is presented together with maternal saliva, the pups will later orient toward orange odor. Thus, conditioning can enhance the value of an unfamiliar odor (Sullivan etal., 1986). 

Woodmice, Apodemus sylvaticus, are able to walk when 11 days old and increase their locomotion between postnatal days 11 and 19. When moving about, they spend more time on home (nest) and male odor than on female odor and clean bedding. This difference is not observed if the woodmice are tested for the first time on day 15, suggesting a critical period for acquiring these odor preferences (Pontet and Schenk, 1988). 

In mammals, early experience with social odors will have lasting effects on odor preferences. We have to distinguishji/w/ (attachment ofyoung... 

Even adults can still develop olfactory preferences that contravene those acquired before sexual maturity. Female laboratory mice imprinted by the odor of one mouse strain will prefer this odor even more if they are exposed to males of this strain as adults. However, if they are exposed to males of a different strain when sexually mature, their original odor preference will be reversed (Albonetti and D Udine, 1986). Naturally occurring sex or body odors may assume their sexual significance after association with sexual activity male mice were aroused by a perfume that they had experienced earlier on scented females they had interacted with (Nyby etal., 1978). Practitioners have known that adult mammals can acquire responses after exposure to certain animals. For instance, bulls of the Asian elephant that had been housed near African elephant bulls respond to temporal gland secretion and its three components phenol, 4-methylphenol, and (E)-farnesol from the latter species. Asian bulls thathad not been associated with African bulls did not respond (Rasmussen, 1988). 

Coopersmith, R. and Leon, M. (1986). Neurobehavioral analysis of odor preference development in rodents. In Ontogeny of Olfaaion Principles of Olfactory Maturation in Vertebrates, ed. W. Breiphol, pp. 237-242. Irvine, CA Department of Psychobiology. 

Doty, R. L. (1972). Odor preferences of female Peromyscus maniculatus bairdii for male mouse odors ofP. m. bairdii and P. leucopus noveboracensis as a function of estrous state. Journal ofComparative and Physiological Psychology 81,191-197. 

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