Importance of mother/young contact at parturition and across lactation for the expression of maternal behavior in rabbits

We prevented mother/pup contact at parturition or across early or midlactation to investigate the importance of such interaction for maintaining maternal behavior in rabbits. When pup contact was prevented across lactation Days 1–7 or 11–17 (by anesthetizing multiparous mothers during the oxytocin-induced milk letdown; Experiment 1), nursing incidence was reduced to 40% and 83%, respectively, on the day following anesthesia withdrawal. Both groups also showed a decreased milk output, long latencies to initiate nursing, and several entrances into the nest box not associated with nursing. In Experiment 2 we prevented mother/litter contact at parturition to determine the specific role of pup contact at this time. We found a reduction in the incidence of nursing on postpartum Day 1 from 80% (in control primiparous mothers) to 33%. By contrast, 100% of both deprived and control multiparous mothers displayed nursing on Day 1. These mothers also showed the unusual behaviors found in Experiment 1 and an extemporaneous nest-building. We conclude that: (a) mother/young contact at parturition is crucial for establishing maternal responsiveness in primiparous does, (b) the experience acquired by raising a previous litter allows the retention of maternal responsiveness despite a lack of pup contact at parturition, (c) maternal responsiveness is maintained across early lactation by daily interaction with pups, and (d) interaction with pups across midlactation allows the finely tuned display of maternal behavior. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 32: 101–111, 1998     

Alterations in the maternal behavior of rats rearing hypothyroid and hyperthyroid offspring

To determine whether maternal behavior could serve as a mediator for thyroid hormone effects on behavior, I assessed nesting, nursing, grooming, contact, and retrieval in mothers of hypothyroid, hyperthyroid, and control litters, as well as in mothers of litters receiving thyroxine replacement therapy. Females assigned to the hypothyroid and replacement therapy treatments were placed on a goitrogenic diet of 2% propylthiouracil from Day 15 of gestation to Day 22 postpartum. Hyperthyroid and replacement therapy pups were injected daily with thyroxine starting on the day of birth. The decline in nesting and nursing was delayed in hypothyroid litters whereas the decline in nesting was accelerated in hyperthyroid litters. Retrieval was not affected, but grooming of pups occurred less frequently in hypothyroid and replacement therapy litters. Maternal care received by hypothyroid pups was considered adequate. Maternal behavior may alleviate some of the effects of perinatal hypothyroidism, but does not seem to be responsible for the more severe effects of hypothyroidism.     

Patterns of maternal behavior in the spontaneously hypertensive rat

Maternal behavior of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive rats was assessed over the preweanling period (days 1-21). Ten litters of each strain were observed during the dark phase of the light:dark cycle using a scan sampling technique. Cages were observed periodically throughout the day and the momentary behavior of the dam was recorded on a checklist of 9 different behaviors. These behaviors included: nursing entire litter, nursing part of litter, contact with entire litter, contact with part of litter, pup carrying/retrieval, licking pups, sniffing pups, nest building, and away from litter. A second set of ten litters per strain was observed in the same manner during the light phase of the light:dark cycle thus providing around the clock data throughout the entire preweanling period. For purposes of data analysis, the 21-day preweanling period was divided into 7 3-day blocks. The mean relative frequency with which each behavior was observed from SHR and WKY mothers was determined for each block and for each phase of the light:dark cycle separately. SHR mothers were with their pups and nursing them more frequently than WKY mothers during the light phase of the circadian cycle. Complimentary to this finding, WKY mothers were observed away from their pups more frequently than SHR mothers during both light and dark phases. Finally, SHR mothers were observed to lick their pups more often than WKY mothers during both phases of the light:dark cycle. These findings were consistent across the entire preweanling period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term effects of prenatal morphine exposure on maternal behaviors differ from the effects of direct chronic morphine treatment

Previous studies have demonstrated that chronic morphine treatment of pregnant rats alters maternal behavior. Other studies have shown long-term effects of prenatal exposure to morphine, including changes in reproductive behavior in adult females. The present study investigated the effects of prenatal morphine exposure on a variety of maternal behaviors such as nursing, maternal activities, nonmaternal activities, and pup retrieval. Prenatal morphine exposure increased active and decreased passive nursing. There were no differences in maternal activities such as presence in the nest, contact with pups, grooming of pups, and/or manipulation of nest shavings. In the retrieval test, prenatally morphine-exposed mothers were faster in carrying the first pup, retrieving the first pup back to the nest, and returning all pups to the nest than prenatally saline-exposed mothers. Maternal and nonmaternal activities also were affected by the light: dark cycle. All saline- and morphine-exposed mothers nursed more, were more often in the nest, and more often in contact with greater than half of their litter during the light than the dark sessions. On the other hand, nonmaternal activities increased during the dark sessions: Mothers cared for themselves (groomed, ate) more and displayed more rearing and sniffing. Mothers spent more time resting with their eyes closed during the light sessions regardless of prenatal drug exposure. The present study demonstrated that the effect of morphine on maternal behavior is different in adult exposed and prenatally exposed mothers. While direct morphine treatment impaired maternal behaviors, prenatal morphine exposure has the opposite effect.     

Effects of mother-litter separation on later maternal responsiveness in the hamster

Primiparous hamsters were permitted either 1,24, or 48 hr of contact with their own litters beginning at parturition followed by varying periods of separation from pups. A different subgroup in each of these 3 conditions was tested for maternal behavior each day starting 24 hr after litter removal. Testing for the display of retrieving and the adoption of the nursing posture using 1–2 day old foster pups continued for each condition until 2 subgroups failed to behave maternally on 2 consecutive days. Nulliparous females were similarly exposed to foster pups and tested at selected intervals; regardless of initial exposure, only 4 of 24 nulliparous animals ultimately displayed maternal behavior. Different primiparous subgroups given 1 hr of exposure were maternal on Days 2–4 postpartum but not on Days 5 or 6 while females in the 24 hr group were maternal on Days 3–5 but not on Days 7 or 8. Groups permitted 48 hr of litter stimulation were maternal through Day 15 postpartum demonstrating that the initial 24–48 hr of pup contact is essential for the development of a long-term mother-young bond.     

Overlapping litters in rats: effects on maternal behavior and offspring emotionality

Female rats have a fertile postpartum estrus, which can result in a simultaneous gestation and lactation and later in the overlapping of two different-age litters. These different physiological and contextual situations may affect the maternal behavior of lactating rats and provoke long-lasting changes in the affective behavior of the litter. Therefore, we aimed to assess the effect of pregnancy and of litter overlapping on the maternal behavior of lactating rats and to describe the maternal- and anxiety-like behaviors of the juveniles that remained in contact with their younger siblings. Results showed that pregnant lactating rats spent more time outside the nest and less time nursing than non-pregnant mothers. On the other side, mothers with overlapping litters licked less the newborn pups than mothers with single litters. These deficits in maternal licking received by neonates were overridden by the juveniles' licking behavior to their younger siblings. Adult male and diestrous female rats reared with younger siblings showed a reduced anxiety-like behavior as compared to age-weaning matched animals without this experience. Thus, natural changes in the reproductive conditions and in the early experience, affect the maternal behavior and long-term modulate affective behavior of the individuals.     

Development of early behaviors in neonatal squirrel monkeys and cotton-top tamarins

The development of simple, nonsocial behaviors was observed in neonatal squirrel monkeys and cotton-top tamarins. One group of observed behaviors included rooting, orienting up, clasping, and grasping, and was assumed to be more directly related to maintenance of maternal contact and nursing than others such as visual and auditory orienting, crawling, walking, and climbing down. Comparison of the results with previously reported data from rhesus monkeys and galagos supported the hypothesis that neonatal behaviors related to maternal contact and nursing persist longer in species with relatively passive maternal behaviors than in species with relatively active maternal behaviors. In contrast, the development of neonatal behaviors not directly related to maternal contact and nursing was not found to vary reliably as a function of species.     

Diurnal and nocturnal nursing behavior in the OLETF rat

The Otsuka Long Evans Tokushima Fatty (OLETF) rat model of obesity has been recently found to develop hyperphagia and obesity early in life. Our goal was to investigate the dams' nursing behavior during the day and the night in order to elucidate their contribution to the pre-obesity of the pups. We examined nursing bout number, length, posture, initiative, nursing total time and frequency of other maternal behaviors over the three postpartum (PP) weeks. In the first week, OLETF dams nursed more during the day and presented more self-directed activities during the night. In the third PP week, OLETF dams displayed increased nursing time, bout number, nursing frequency, and supine postures at the beginning of the nursing episodes and less active self-directed behaviors, both day and night, while OLETF pups displayed more initiative in starting nursing bouts. The results suggest a circadian difference in nursing behavior and self-directed activities between the strains on PP week 1 and a strong influence of the OLETF pups on the nursing behavior of the dam on PP week 3, which contributes to their obese features.     

Diurnal and nocturnal nursing behavior in the OLETF rat

The Otsuka Long Evans Tokushima Fatty (OLETF) rat model of obesity has been recently found to develop hyperphagia and obesity early in life. Our goal was to investigate the dams' nursing behavior during the day and the night in order to elucidate their contribution to the pre‐obesity of the pups. We examined nursing bout number, length, posture, initiative, nursing total time and frequency of other maternal behaviors over the three postpartum (PP) weeks. In the first week, OLETF dams nursed more during the day and presented more self‐directed activities during the night. In the third PP week, OLETF dams displayed increased nursing time, bout number, nursing frequency, and supine postures at the beginning of the nursing episodes and less active self‐directed behaviors, both day and night, while OLETF pups displayed more initiative in starting nursing bouts. The results suggest a circadian difference in nursing behavior and self‐directed activities between the strains on PP week 1 and a strong influence of the OLETF pups on the nursing behavior of the dam on PP week 3, which contributes to their obese features. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 203–203, 2008.     

金属对金属髋关节动态边缘接触力学行为

目的研究球面共型接触人工髋关节在股骨头动态位移条件下的边缘接触力学行为。方法基于所发展的有限元球面网格数据模型,动态模拟分析金属对金属人工髋关节在给定生理位移工况条件下的接触行为和可能诱发的边缘接触现象。结果数值模拟表明,随着动态位移载荷的增加,关节接触面压力合力的垂直分力和水平分力都有上升趋势;在边缘接触过程中压力合力的垂直分力比非边缘接触情况变化趋势要缓慢,但相应的水平分力增大趋势更显著。此外,边缘接触与非边缘接触对应的接触压力分布形态与接触区域也各不相同。结论金属对金属人工关节髋臼相对股骨头过大的倾斜状态极易引起边缘接触,动态边缘接触情况下,将导致股骨头向髋臼内侧产生相对滑动及附加磨损的可能,这对临床人工髋关节磨损评估与关节制造发展提供了分析依据。     

Trigeminal lesions and maternal behavior in Norway rats: III. Experience with pups facilitates recovery

In lactating rats, upper snout desensitization by trigeminal denervation severely impairs maternal behavior, with substantial recovery 12–24 hr later. The potential effects of interaction with pups on this recovery was investigated. Dams were subjected to bilateral infraorbital denervation or sham surgery on Day 5 postpartum and observed for 30 min with 6 foster pups 24 hr later, after separation from pups for 4 or 24 hr. Long separation reduced likelihood of retrieval and nursing behavior, infraorbital denervation reduced duration of pup licking, and these deprivations combined greatly increased latencies of pup sniffing and durations of facial self-grooming. Both conditions, and especially their combination, prolonged retrieval duration, the retrieval sequence being interrupted by other pup contact, such as licking. Thus, interaction with pups and adequate trigeminal stimulation maintain normal maternal behavior. These findings are possibly relevant to the normal decline of maternal responsiveness during late lactation and to other lesion-induced deficits. © 1997 John Wiley & Sons, Inc. Dev Psychobiol 30: 115–126, 1997     

Nursing behavior in rats is impaired in a small nestbox and with hyperthermic pups

The supine nursing posture, which occurs increasingly as growing pups initiate nursing from their recumbent dam, was demonstrated to require more space than that provided in earlier studies of mother-young contact (e.g., Leon, Croskerry, & Smith, 1978). Further, hyperthermic rat pups were shown to be deficient in eliciting normal nursing behavior. During a 4-hr separation from their dam, 7-day-old rat pups were incubated at 34°C (nest temperature) or at 39°C (WARM). Compared to controls, WARM-litter dams showed increased licking of and hovering over pups and decreased upright crouching, while WARM litters showed decreased nipple attachment and weight gain. On Day 13, similar effects occurred after incubation at 39°C (vs. 34°C), but not at 36 or 38°C. The results stress the need for ethologically meaningful conditions and direct behavioral observations to reveal the importance of pup activity in the mother-young dyad. © 1996 John Wiley & Sons, Inc.     

Maternal behavior of primiparous females in inbred strains of mice: a detailed descriptive analysis

In the present study, we compared the maternal and non-maternal behaviors of primiparous females in both the light and dark phases during 3 weeks postpartum in five inbred strains of mice (BALB/c, CBA/Ca, C3H/He, C57BL/6, and DBA/2) to examine the strain differences in the behaviors in detail. Generally, nursing postures (arched-back, blanket, and supine) and pup lickings (anogenital and body) occurred more frequently in the light phase, whereas nest building occurred more frequently in the dark phase. As pups grew, arched-back and blanket nursing, anogenital and body licking, and nest building decreased, but supine nursing slightly increased. The present results revealed strain-specific variations in maternal behavior. In general, BALB did not engage in maternal behavior very vigorously, but the other four strains actively did. The patterns of strain differences were not parallel between the subcomponents of nursing posture or pup licking. CBA showed more arched-back and supine nursing, and DBA showed more blanket nursing. C57 and CBA showed more anogenital licking, while C3H and DBA showed more body licking. Strain differences were also found for the changes across postpartum days in almost all behaviors. These findings provide information to examine the effects of genetic and environmental factors on the development of maternal behavior in mice.     

Mother and newborn baby: mutual regulation of physiology and behavior--a selective review

This article reviews 30 years of work demonstrating that interactions between mother and newborn infant in the period just after birth influence the physiology and behavior of both. Close body contact of the infant with his/her mother helps regulate the newborn's temperature, energy conservation, acid-base balance, adjustment of respiration, crying, and nursing behaviors. Similarly, the baby may regulate--i.e., increase--the mother's attention to his/her needs, the initiation and maintenance of breastfeeding, and the efficiency of her energy economy through vagus activation and a surge of gastrointestinal tract hormone release resulting in better exploitation of ingested calories. The effects of some of these changes can be detected months later. Parallels to animal research and possible mechanisms are discussed.     

Comparison of the effects of early handling and early deprivation on maternal care in the rat

It has been reported in the rat that postnatal manipulations can induce robust and persistent effects on offspring neurobiology and behavior, mediated in part via effects on maternal care. There have, however, been few studies of the effects of postnatal manipulations on maternal care. Here, we describe and compare the effects on maternal behavior on postnatal days 1-12 of two manipulations, early handling (EH, 15-min isolation per day) and early deprivation (ED, 4-hr isolation per day), relative to our normal postnatal husbandry procedure. Maternal behavior was measured at five time points across the dark phase of the reversed L:D cycle. EH yielded an increase in arched-back nursing across several time points but did not affect any other behavior. ED stimulated a bout of maternal behavior such that licking and arched-back nursing were increased at the time of dam-litter reunion, although not at any other time point. Neither EH nor ED affected weaning weight significantly. Importantly, within-treatment variation was high relative to these between-treatment effects.     

Thermal control of mother-young contact revisited: hyperthermic rats nurse normally

Morphine (MOR) is known to inhibit maternal behavior and induce hyperthermia; at appropriate doses, concurrent administration of naloxone (NAL) counteracts its disruption of maternal behavior but not the hyperthermia. We used these findings to evaluate the view that lactating rats terminate nursing due to intolerable hyperthermia. After a dam-litter separation of 4 h on Day 7 postpartum (PP), mother-litter interactions were observed continuously for 1 h. One hour before reunion, the dams received two injections (1 ml/kg ip each) of saline (SAL), MOR (20 mg/kg) and/or NAL (1 mg/kg) in the following combinations (n = 7 each): SAL + SAL, SAL + NAL, MOR + SAL or MOR + NAL. MOR profoundly disrupted maternal behavior, thereby preventing litter weight gains; these effects were completely counteracted by NAL, which alone had no discernible effects. In contrast, MOR-induced hyperthermia (approximately 0.7 degrees C increase in each hour, before and after reunion with pups) was not antagonized by NAL at the doses used. Thus, an additional 0.7-1.4 degrees C of body temperature (T) did not delay the onset or reduce the duration of nursing compared with SAL-treated controls. Further, there were no group differences in behaviors displayed both shortly before and after a nursing bout that included milk ejections or in the resumption of nursing. Together with earlier methodological and empirical criticisms of the thermal control theory, as well as knowledge about the somatosensory determinants of nursing, the present results suggest that nursing bouts in lactating rats are not limited by the mother's T.     

Comparison of the parental behavior of pair-bonded female and male prairie voles (Microtus ochrogaster)

The behavior of primiparous lactating prairie voles (Microtus ochrogaster) and their mates individually interacting with pups was continuously assessed for 45 min after a 2-h parent-litter separation on days 3-4 and 10-11 postpartum. Both sexes were highly parental after reunion with the young, and their general pattern of behavior consisted of bouts of quiescence interspersed with bursts of heightened activity. Lactating females spent more time than males in contact with pups, and more time being quiescent, most often in the kyphotic (upright crouched) nursing posture. Even in the absence of nipples upon which the pups could suckle, males also displayed kyphosis, although for shorter durations than females. Males spent more time, however, huddled over the litter in a hunched position than their mates. In accordance with their decreased quiescence, male voles licked and carried pups more and were more exploratory than females. Compared with the first week postpartum, bouts of kyphosis were shorter during the second week postpartum for both sexes, while laying prone on the pups increased. Males spent less time licking and more time carrying older pups than younger ones, and were more exploratory during the second week postpartum. Sex differences in the parental behavior of prairie voles may reflect differences in the somatosensory stimulation that females and males receive from pups. Furthermore, the display of kyphosis by male voles indicates that the sensorimotor organization of this posture in voles differs from that of lactating rats, which require suckling stimulation for its regulation.     

Differential effects of progesterone on lactation and nursing behavior in late pregnant and postparturient rats

In the past, studies on the effects of progesterone injections before or after birth concentrated only on lactation or nursing behavior. The present study is a report of the effects of progesterone on both events, in the same strain of rat, across a number of groups, administered either during pregnancy or after birth. In the first part of the experiment, 2 mg doses of progesterone subcutaneously were injected into nulliparous Sprague-Dawley rats from Days 18–23 of gestation. The injections delayed the onset of birth, caused a high mortality among young, and produced young that failed to thrive. In spite of this, nursing behavior appeared normal. There were no significant differences in the latency or duration of crouching behavior between the progesterone and oil-injected control groups. Thus the difficulties appeared to be with lactation. Because mammary glands contained milk, problems with secretory activation in the glands were ruled out. Even though the pups suckled teats, they got no milk, suggesting dysfunctions in milk release. To determine whether progesterone might alter maternal behavior once it was established after birth, 2-mg doses of progesterone were injected during the first postpartal week. They were found to depress litter weights and increase the latency to crouch over pups. During the second postpartal week, the injections reduced the latency to crouch, causing females to act vigorously toward pups at a time when maternal behavior typically starts to decline. Thus, depending upon the stage of the reproductive cycle in which progesterone is introduced, it can either inhibit or enhance nursing behavior. Moreover, the action of progesterone during late gestation appears to be only on milk release.     

Sucking,not milk,is important for the rapid learning of nipple-search odors in newborn rabbits

Newborn rabbits are only nursed once a day for 3 to 4 min and are completely dependent on a pheromone on the mother's ventrum for the release of nipple-search behavior and sucking. However, if the mother's ventrum is perfumed, pups can be conditioned in just one 3-min nursing session to respond with nipple searching to the novel odorant. To define more precisely the reinforcing properties of the nursing situation supporting such rapid learning, odor conditioning was conducted in independent groups of 2-day-old pups after successively eliminating potential reinforcing stimuli such as the doe's behavior, milk ingestion, nipple-search behavior, or sucking nipples. All experimental groups showed significant conditioning compared to control groups subjected to similar treatments on unscented does, with the strength of conditioning indicating that behavior of the doe, milk consumption, or arousal during performance of the search behavior were not major reinforcers, but rather the opportunity to suck nipples. Thus, this study suggests intraoral stimulation associated with sucking to be an important reinforcer in this paradigm, as for early olfactory learning in other young mammals.     

心理护理及语言沟通在临床精神科护理中的作用分析

目的 探讨心理护理及语言沟通技能在临床精神科护理中的作用。方法 选取2015年3月~2017年3月在本院精神科住院的100例患者,随机分为观察组和对照组,每组50例。对照组仅采取常规物理治疗,观察组在对照组基础上辅以心理护理和语言沟通,2年后对比两组患者性格改变发生率、行为异常发生率、言语异常发生率及病情发生率,并对两组患者病情发生率进行单因素方差分析。结果 观察组的性格改变发生率、行为异常发生率、言语异常发生率及病情复发率均低于对照组,差异有统计学意义（P＜0.05）。病情发生率经单因素方差分析可知,心理护理在临床精神科治疗中有显著疗效。结论 在临床精神科护理中运用心理护理和语言沟通技能,可以有效调节患者情绪,控制患者病情,从而促进其心理康复。