摘要:

AbstractFreely‐moving, posthatch chicks were individually presented 2 concentrations each of quinine, citric acid, fructose, sucrose, sodium saccharin, and distilled water and their behavioral reactions were videotaped and analyzed. Already during the first posthatch day distinct rejection responses to quinine and citric acid could be recognized. Prolonged head shaking and beak clapping episodes were the most dominant features of these reactions. While responses to water and sweet stimuli could be interpreted as acceptance behaviors, the resolution was generally not fine enough to discriminate between reactions to the 2 different sweet concentrations of these stimuli or between them and water. When only water or sugar solutions were presented to other hatchlings in a single session. There was a suggestion of more definite acceptance behavior to some sweet stimuli as compared to water. It is concluded that the systems mediating aversive gustatory responses are present and functioning in posthatching chicks while acceptance responses, though present, are less discriminative among stimul

ISSN:0012-1630    

DOI:10.1002/dev.420230202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe present status of knowledge on early inhibitory learning and memory is presented. The inhibitory learning (passive avoidance) can be mastered by rat pups several hours after parturition, provided specific characteristics of the newborn organism and its neurobehavioral capabilities are respected. The curve of numbers of trials to criterion displays, as already reported earlier, a generally decreasing trend which is, however, interrupted by a temporary inversion in both strains studied, but at different time, taking place in Long Evans between postnatal day 1 and 2, which is shifted in Wistar pups one day later. Present data show significant learning differences between strains at postnatal days 1–4; from day 5 onward no significant differences are evidenced up to postnatal day 11. A reliable 24‐hour memory shown by positive values of the retention index (RI) is revealed from postnatal day 4, having in Long Evans higher RI values. Moreover, high positive RIs of 24‐hour memory are found in animals trained on the day just before the inversion of the learning development. It is conjectured that the indirect development of the early inhibitory learning is due to the developmental reorganization within CNS, and the necessity to find out its underlying mechanisms is empha

ISSN:0012-1630    

DOI:10.1002/dev.420230203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractSocially housed leghorn cockerels were confined to a heated grid (55, 57, or 59°C, Experiment 1; 59, 61, or 63°C, Experiment 2) and tested at posthatch ages of 14 days (Experiment 1) and 1, 3, 7, or 14 days (Experiment 2). In Experiment 1, chicks performed a discrete jump response only at 59°C. In Experiment 2, jump latency was inversely related to temperature at each age but significantly so only at 7 and 14 days posthatch. At the highest temperature, jump latency did not differ significantly across ages. At medium and low temperatures, latency increased from 1 and 3 to 7 days posthatch (antinociceptive effect) and decreased thereafter. Chicks raised in isolation from hatch to 7 days posthatch (Experiment 3) did not display the increased jump latency (antinociceptive effect) displayed by socially raised chicks. Developmental increases in jump latency may reflect stress‐induced antinociceptive concomitants of neophobia that emerge with age in this precocial species and social experience may be required for the normal development of this stress‐induced antinocic

ISSN:0012-1630    

DOI:10.1002/dev.420230204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn three experiments the effects of dopamine receptor antagonists on response‐contingent punishment and autoshape learning of 1‐ and 4‐day‐old chicks were determined. In the first two experiments, 1‐ or 4‐day‐old chicks (N = 120) were trained to key‐peck for heat reward and then injected intraperitoneally (ip) with either haloperidol (1.5, 2.5, or 5.0 mg/kg) or saline (Experiment 1) and with either haloperidol (2.0 mg/kg), sulpiride (50 mg/kg) or saline (Experiment 2) 30 min before a 96‐trial response contingent punishment session. In Experiment 3, 1‐ and 4‐day‐old chicks (N = 48) were injected ip with saline or haloperidol (2.0 mg/kg) 30 min prior to a 30‐trial autoshape learning session. In both the punishment and appetitive tasks 1‐day‐old chicks pretreated with either haloperidol (1.5 to 2.5 mg/kg) or sulpiride showed a significant increase in key‐peck responding compared with their saline injected controls. In contrast, 4‐day‐old chicks given either haloperidol (2.0 mg/kg) or sulpiride did not differ significantly from saline treated chicks on the punishment task, and on the autoshape task haloperidoltreated 4‐day‐old chicks responded on fewer trials than did their saline controls. These results indicate that dopaminergic synaptic transmission in the young chick as measured by dopamine D2receptor blockers is functionally dif

ISSN:0012-1630    

DOI:10.1002/dev.420230205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe present report examined the effects of undernutrition and handling on shuttle and footshock escape avoidance behavior of female rats. Rats were undernourished by feeding their dams a 7% casein diet from birth until 23 days of life. During this period rats were separated from their dams for 4 to 10 min. On days 23 and 24 after delivery, young rats were subjected to sessions in a two‐way shuttle avoidance task. The results demonstrated that nonstimulated and stimulated undernourished and stimulated well‐nourished rats escape faster than nonstimulated well‐nourished animals from footshock during the first session of shuttle avoidance. Further, undernutrition interacted with early stimulation, disrupting the shuttle avoidance behavior of female rats. These results suggest that both undernutrition and early handling can change the footshock behavior of young rats. Undernourished rats presented lower basal glucose levels than well‐nourished animals, but responded to shuttle avoidance testing in the same way as do normal rats, increasing the glucose

ISSN:0012-1630    

DOI:10.1002/dev.420230206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe contribution of diet and surgery to the brain weight deficits observed in artificially reared rats was investigated. Four day old Long Evans rat pups were assigned to an artificially reared (AR) or mother reared (MR) group. AR pups were encannulated and fed either rat milk (AR‐MOM) or replacement formula (AR‐MES). MR. pups received a sham encannulation (MR‐SHAM) or no surgery (MR‐CONT) before being returned to their dam for rearing. On day 7 all the animals were killed. Brain weights and visceral organ weights were obtained. There was no significant difference between the MR groups on any measure except stomach weights. AR‐MOM pups had larger visceral organ weights than pups in the other groups. AR‐MOM and AR‐MES pups had similar whole brain weights, smaller than those of the MR pups. However, the cerebellar weights, and to a lesser extent, brainstem weights, showed improvements in the AR‐MOM group, over the AR‐MES group. Neither the effect of surgery nor of diet alone can account for the organ weight differences that have been described in AR rats. The possibility that normal growth may be primarily dependent on diet at one stage of development, with other factors gaining importance at later st

ISSN:0012-1630    

DOI:10.1002/dev.420230207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA new method for administering a taste to preterm and term infants has been developed that does not necessitate the delivery of sapid solutions. Sucrose, a sugar that in solution was shown to potentiate sucking behavior, was embedded in gelatin‐based nipples that continuously release sweet taste when mouthed or sucked. The gelatin nipple and comparable latex nipples were adapted to measure sucking behavior and were tested in a within‐subject design. The gelatin nipples potentiated sucking in preterm and term infants by increasing the frequency and strength of the responses. Few sucking measures varied significantly for preterm and term infants. Those that did vary might be attributable to differences in physical stamina, rather than to orosensory orhedonic factors. It was concluded that the flavored gelatin nipple provides an effective method for studying taste in infants and offers the possibility of routine chemosensory stimulation for research and clinical applicati

ISSN:0012-1630    

DOI:10.1002/dev.420230208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420230201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY