Olfactory, thermal, and tactual influences on infantile ultrasonic vocalization in rats

Abstract

The amount of time infant rats 3-13 days old spent emitting ultrasounds was greater when pups were placed in an empty dish than when placed in a dish containing clean bedding or soiled bedding from the nest. Pups from 5-13 days of age vocalized more when on the clean bedding than when on the soiled bedding. When placed on cloth covered dishes, pups vocalized most to the empty dish and least to the dish containing soiled bedding. The odor of clean bedding elicited less ultrasonic vocalization than the odor of the empty dish only when less than 7 days old. Pups vocalized more to room temperature than to heated conditions. The results indicate that olfactory, tactual, and thermal nest cues influence infantile ultrasonic vocalization in the rat.

Acquisition and expression of a socially mediated separation response

“…That it does has been known since the very earliest studies [1,80,82]. But the results do show that the function of USV as frequently tested, e.g., during brief isolations at room temperature, is not part of a thermogenic response.…”

“…The effects of an infant's formation of early life relationships and its social interactions with caretakers are known to last well in to adulthood with both beneficial and harmful effects [28,35,70]. In our laboratory, we study the development of social relationships between infant rats and their dams, sires, and littermates using an isolation, reunion, and re-isolation test paradigm.Infant rats emit ultrasonic vocalizations (USV) in a variety of situations, including as a response to isolation, physical manipulation, and thermal and olfactory challenge [1][2][3]6,19,25,46,79,80,82,97]. Many researchers have used the presence and absence of these sounds to make inferences about the internal state of the rodents, e.g., isolation-induced USV's have often been called "distress vocalizations" [29,76,78].…”

Fatty Acids and Emotional Behavior

“…Schapiro and Salas (1970) demonstrated that exposure to maternal odors in rat pups before weaning reduced the movements of pups. Oswalt and Meier (1975) found that infant rats reduce their emission of ultrasonic vocalizations when exposed to maternal odors. Therefore, maternal litter or home odors produce signs of calm.…”

USAF Summer Research Program - 1995 Summer Faculty Research Program, Final Reports, Volume 2A, Armstrong Laboratory.

“…Most authors report that, for pups 2 weeks old or older, cues other than temperature come into play and influence the rate of vocalization. These cues include the presence of conspecifics (Hofer & Shair, 1978, 1980, handling or 4-4 tactile cues (Gardner, 1985;Okon, 1972;EIsner et al, 1990), olfactory cues (Conely & Bell, 1978;Oswalt & Meier, 1975;Lyons & Banks, 1982), nutritional cues (Blass & Fitzgerald, 1988;Shide & Blass, 1989), and other contextual factors (e.g., learning, Amsel et al, 1977).…”

“…In some of the work of Hofer and colleagues (e.g., Hofer & Shair, 1978;1980), as well as some earlier research (e.g., Oswalt & Meier, 1975) there have been attempts to control various factors and test cues in isolation from one another. Hofer & Shair (1980) found that tactile, temperature, and odor cues were all important in influencing UV emission rate in isolated 2-week-old pups.…”