Developmental Psychobiology

doi: 10.1002/dev.420260201pmid: N/A

Hofer, Myron A.; Brunelli, Susan A.; Shair, Harry N.

doi: 10.1002/dev.420260202pmid: 8467962

In order to assess the importance of maternal thermal cues in controlling the acute USV responses of rat pups to contact with her body (the contact comfort response) and to separation from her, we drastically altered maternal temperature by inducing severe hypothermia so that maternal rectal and flank temperatures averaged more than 20°C below normal and 10°C below ambient levels during testing. Isolated 12‐ to 13‐day‐old pups showed reductions in USV when these cold dams were presented and brisk USV accelerations when the cold dams were removed from the test chamber. These responses closely resembled those of other pups tested with warm (36°C) anesthetized dams. No significant differences were found in pups' USV contact comfort responses to cold and warm dams. For acute separation, prior maternal thermal properties and other factors were found to modulate the relative intensity of the marked USV increase elicited by this event © 1993 John Wiley & Sons, Inc.

Leshem, Micah; Langberg, Joely; Epstein, Alan N.

doi: 10.1002/dev.420260203pmid: 8467963

The ontogeny of the behavioral ability to compensate for sodium deficit was studied in the rat. The experiments showed that: (1) Before weaning age, sodium‐depleted pups will increase their avidity for 3% NaCl solution; (2) the ability to select and drink a salt solution in response to a sodium deficit continues to evolve between 17–24 days of age, and that pups at these ages will modify their intake of salt and water as do adult rats when rectifiying plasma osmolality; (3) The increased appetite for sodium is evident even when depleted preweanlings are dehydrated and provided with solid NaCl tablets to lick, showing that sodium appetite and hydrational status are already dissociated at this age; and finally, (4) sodium depletion first induces an increase in intake of orally infused 3% NaCl solution in 12‐day‐old pups. The picture of the development of salt appetite in the suckling rat that these findings present is of a precocious competence to meet a challenge to sodium homeostasis. In this respect salt appetite emerges in parallel to the other ingestive behaviors © 1993 John Wiley & Sons, Inc.

Fleming, Alison S.; Corter, Carl; Franks, Patrícia; Surbey, Michelle; Schneider, Bruce; Steiner, Meir

doi: 10.1002/dev.420260204pmid: 8467961

Hedonic responses to a variety of infant (general body, urine, and feces) and noninfant (lotion, cheese, and spice) odorants were compared in four groups of subjects: new mothers, mothers a 1‐month pospartum, and female and male nonparents. Using standard scaling procedures, subjects rated each of the odorants twice on a scale from extremely unpleasant (−20.5) to extremely pleasant (+20.5). In addition, all subjects completed a set of attitude questionnaires, and mothers also answered a childbirth questionnaire and were observed while feeding their infants © 1993 John Wiley & Sons, Inc.