RESUMO
Newborn rabbits, like other altricial mammals, demonstrate thermotaxis and when placed on a thermal gradient locate and come to rest at physiologically appropriate temperatures. Little is known, however, about the sensory-motor components contributing to the in energetic terms important decision of the young to cease locomotion and come to rest. We investigated the behavior of newborn rabbits on two thermal gradients; linear in which pups could use tactile cues from the arena wall, and concentric in which pups were unable to use such cues. On both gradients pups located the warm, thermal-neutral area within the 200-s test time, thereby demonstrating their ability to orient appropriately using thermal cues alone. Unexpectedly, however, pups on the concentric gradient failed, or took significantly longer, to come to rest than pups on the linear gradient. Since the speed of locomotion of pups on the linear gradient was significantly slowed when they were in contact with the arena wall, and in most cases they came to rest in contact with it, we suggest that not only thermal but also tactile cues may be important in bringing young mammals to rest in a thermally appropriate environment.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Sinais (Psicologia) , Temperatura Alta , Tato/fisiologia , Animais , Animais Recém-Nascidos , Comportamento Animal , Locomoção , Privação Materna , Atividade Motora , CoelhosRESUMO
In this study, 40 Japanese, 44 German and 39 Mexican women were presented with 18 everyday odorants. They were asked to rate them for intensity on a six-point scale from not detectable to very strong, for pleasantness on an 11-point scale from -5, to neutral at 0, to +5, and for familiarity on a six-point scale from completely unknown to extremely familiar. Consistent positive correlations were found between paired rating scores for the three measures, and although they were not particularly strong (r(s) range, 0.19-0.60), for most odorants all three correlations were significant. Similar results were obtained whether the data were analyzed on an individual or a national basis. Most notable were the consistent positive correlations between perceived intensity and ratings of familiarity and hedonic strength. It is suggested that the perceived intensity of the odorants depended not only on stimulus concentration but probably also on experience-dependent factors.
Assuntos
Memória , Odorantes , Olfato , Adulto , Etnicidade , Feminino , Alemanha , Humanos , Japão , México , Pessoa de Meia-Idade , Estatística como AssuntoRESUMO
Despite the importance of chemosensation in the regulation of ingestive behavior, we still know surprisingly little about the development of the olfactory, trigeminal and gustatory systems. All three, however, are functional to some degree prenatally, and by birth infants are able to respond to a wide range of odors and can clearly distinguish between the tastes of sweet, sour and bitter. Based on findings from our work in the rabbit, we report that learning of odors associated with the mother's diet can occur very early in development, even prenatally, that it can have a long-term influence on later food choice, and may even lead to enhanced, stimulus-specific sensitivity of the basic sensory apparatus. Whether comparable phenomena exist in human infants is not known, although our recent findings that nationalities differ in judgements of the pleasantness of food odors depending on whether these are recognized as representing familiar, culture-typical foods, suggests that it might. A cross-cultural study is currently in progress examining the influence of culture-specific childhood eating experiences on adult preferences for food-associated odors.
Assuntos
Preferências Alimentares/psicologia , Odorantes , Olfato , Paladar , Adulto , Animais , Comparação Transcultural , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal , CoelhosRESUMO
The high dimensionality and unpredictability of the chemical world makes it difficult for the olfactory system to anticipate relevant stimuli and construct neural filters accordingly. A developmental solution to this problem would be to alter the sensory surface according to environmental conditions so as to enhance sensitivity to molecules of particular relevance. Evidence for this has been obtained in the rabbit. By feeding pregnant does aromatic juniper berries, it could be shown that newborn, weanling and even adult animals demonstrate a preference for juniper odor without subsequent postnatal experience, and that this is associated with enhanced peripheral sensitivity for juniper odor as measured by electro-olfactogram (EOG). This is consistent with the report that in young salmon olfactory imprinting is associated with enhanced, odor-specific sensitivity of receptor cells as measured by patch clamp. The mechanisms underlying such changes are unknown, including the extent to which they are a particular feature of developing systems.