Maternal performance of inbred and hybrid laboratory mice (Mus musculus).

60 primiparous mice from 3 inbred strains (A/J, DBA/2J, C57BL/6J) and their reciprocal crosses were subjected to various tests of maternal behavior. During pregnancy, S was placed in a seminaturalistic environment, and her nest-building activity was assessed. Following parturition, S's retrieval behavior was measured under conditions that placed conflicting demands on her behavioral repertoire. Results indicate that there were both qualitative and quantitative differences between inbred and hybrid Ss. Prenatal nest-building activity showed heterosis on various measures of relevant environmental manipulations. The retrieval data suggest that inbred Ss were less able to integrate their behavior into a coherent pattern. The level of inbreeding of the pups had no significant effect on the aspects of maternal behavior measured. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol withdrawal severity in inbred mouse (Mus musculus) strains.

Male mice (Mus musculus) from 15 standard inbred strains were exposed to a nearly constant concentration of ethanol (EtOH) vapor for 72 hr, averaging 1.59 ± 0.03 mg EtOH/mL blood at withdrawal. EtOH- and air-exposed groups were tested hourly for handling-induced convulsions for 10 hr and at Hours 24 and 25. Strains differed markedly in the severity of withdrawal (after subtraction of control values), and by design these differences were independent of strain differences in EtOH metabolism. Correlation of strain mean withdrawal severity with other responses to EtOH supported previously reported genetic relationships of high EtOH withdrawal with low drinking, high conditioned taste aversion, low tolerance to EtOH-induced hypothermia, and high stimulated activity after low-dose EtOH. Also supported were the positive genetic correlations among EtOH, barbiturate, and benzodiazepine withdrawal. Sensitivity of naive mice to several chemical convulsant-induced seizures was also correlated with EtOH withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-dependent genetic influences on behavioral response of mice (Mus musculus) to acetaldehyde.

Employed acetaldehyde as a pharmacological agent in behavioral tests designed to assess genetic influences on response to the drug. When used as a poison in a conditioned taste aversion study with 200 male mice, acetaldehyde was more effective at inducing aversions in DBA/2J mice than in C57BL/6J mice. In another experiment, however, 6 C57 mice were more affected than were 6 DBA mice by acetaldehyde effects on loss of righting reflex. Implications for postulated genetic control of ethanol preference and neurosensitivity are discussed. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observational learning of a left-right behavioral asymmetry in mice (Mus musculus).

B6D2F? hybrid mice that were allowed to observe a trained female mouse open a pendulum door to the right (or to the left) to enter a food compartment later solved this problem faster than pupils that had been placed behind a visual barrier. Male pupils that had observed a "left-handed" teacher performed sinistrally; males that had observed a "right-handed" model performed dextrally. Female pupils did not exhibit their demonstrator's laterality. Observational learning may provide a means to maintain certain lateralized behaviors. Such social learning may lead to the emergence of local traditions and to the cultural diffusion of behavioral asymmetries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual dimorphism in ultrasonic vocalizations of mice (Mus musculus): Gonadal hormone regulation.

Male mice, during courtship and sexual behavior, vocalize substantially more 70-kHz ultrasounds than do females. Four experiments conducted with 109 male and female DBA/2J and ADK2F? mice demonstrated that testosterone propionate (TP) substantially increased ultrasonic emissions and mounting by ovariectomized females and that long-term gonadectomized males and females increased their amount of ultrasound production in response to TP to approximately the same levels. From these results it is suggested that the sexual dimorphism normally seen in ultrasonic vocalizations can be accounted for by the activational effects of androgen in adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Male acceleration of puberty in female mice (Mus musculus).

Nine experiments investigated various aspects of the acceleration of puberty in female ICR/Alb house mice (N?=?754) produced by the presence of a male mouse or urine from males. Grouping males had no effect on the urinary chemosignal that accelerates puberty, except that urine from dominant males produced greater acceleration than urine from subordinates. Young female mice must be exposed to the male urine for at least 2–3 hrs/day or to the presence of a male for 1 hr/day to produce acceleration of first vaginal estrus. Females were accelerated to the same extent in attaining puberty whether treated with urine from the same male or a different male each day. Urine from the father or a full brother, or the presence of those close relatives, exerted no differential acceleratory or retarding effect on puberty when compared with urine from or the presence of unrelated males. Excreted or bladder urine from adrenalectomized males accelerated puberty to the same extent as urine from intact males, but the presence of an adrenalectomized male did not produce the same degree of acceleration as when an intact male was present. Behavioral observations indicate that adrenalectomized males pursued young females less and attempted fewer mounts during a brief test period. Implications are noted for the understanding of both the mechanisms of acceleration of puberty in the house mouse and the population and reproductive biology of these mice. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonic vocalizing by adult female mice (Mus musculus).

Conducted 5 experiments, using 1,029 female and 805 male mice, to examine adult female mouse ultrasound emission. Results indicate female ultrasonic vocalizing to be (a) typically displayed among female mouse dyads and (b) comparable to the ultrasonic vocalizing levels obtained among male–female pairs. Genotypically based variations in the production of ultrasounds by females were also noted. Like males, socially naive females readily ultrasonically vocalized to anesthetized female conspecifics and rarely vocalized to anesthetized males. Unlike males, socially experienced females emitted few ultrasounds to either female urine or female-soiled cage shavings. Although social experience increased the ultrasound emission of males to female sex cues, the production of ultrasounds by females to these cues was decreased by social experience. Implications with regard to the existence of a behavioral/functional sexual dimorphism in adult mouse ultrasonic vocalizing are discussed. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Of mice (Mus musculus) and toddlers (Homo sapiens): Evidence for species-general spatial reorientation.

There is ongoing debate in spatial cognition about the mechanisms by which organisms are able to reorient, or reestablish a position, in the world after losing their bearing. The traditional view is that there is an encapsulated reorientation module that can only process environmental geometry such as distances or angles (Cheng, 1986). Recently, this view has been challenged on the grounds that the reorientation mechanism is only able to accept geometric information and may instead depend on a more general ability to use relative cues. J. Huttenlocher and S. F. Lourenco (2007) demonstrated that toddlers are successfully able to reorient with continuous cues but show remarkable deficits using categorical cues that are similar in perceptual complexity for reorientation. Here, the authors show the same pattern of results with mice (Mus musculus). These findings provide evidence that there is a homologous reorientation mechanism between mice and humans. Thus, future researchers can examine the genetic basis of this important cognitive ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characteristics of thirst and sodium appetite in mice (Mus musculus).

Intakes of water and NaCl solution were examined in mice following treatment with agents that stimulate or mimic components of the renin-angiotensin-aldosterone system. Injections of angiotensin II or isoproterenol produced little water intake compared with robust responses to either intracellular dehydration or extracellular dehydration induced by treatment with polyethylene glycol. In studies on appetite for NaCl solution, mice exhibited no spontaneous preference for NaCl solution over water and did not change this preference during treatment with deoxycorticosterone acetate, a sodium-deficient diet, or after adrenalectomy. Plasma concentrations of aldosterone were increased in intact mice fed a sodium-deficient diet but not eliminated by adrenalectomy. Acute treatment with furosemide in combination with a sodium-deficient diet stimulated an appetite for NaCl solution. Chronic oral administration of an angiotensin I converting enzyme inhibitor failed to induce a NaCl appetite. Findings show that mice are refractory to the induction of water or NaCl intake by stimuli of the renin-angiotensin-aldosterone system, highly effective in rats, suggesting that there may be major differences among rodents in hormonal determinants of behaviors related to hydromineral homeostasis. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Behavioral development and strain differences in perinatal mice (Mus musculus).

Examined the perinatal development of spontaneous body movements and reflexes in Slc:ICR, C3H/He, and BALB/c mice. Mice were observed from Day 18 (a day before normal parturition) to Day 21.5 of gestation. The developmental changes of spontaneous body movements and reflexes occurred quickly. Strain differences in behavioral development were detected in the duration of spontaneous body movements but not in the occurrence of reflexes. Hybrid mice were more active than their parental strains with regard to duration of spontaneous body movements. The rooting reflex and crossed extensor reflex in hybrid mice occurred more frequently on Day 18 than in their parental strains. These results indicate that the perinatal period is characterized by quick qualitative and quantitative changes in behavioral development and by the appearance of these genetic differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic influences on digging behaviors in mice (Mus musculus) in laboratory and seminatural settings.

Examined digging behaviors of several inbred strains of laboratory mice and some of their crosses in 3 contexts. In laboratory burrow boxes, C57BL/6Abg mice constructed more sophisticated burrow systems than did BALB/cAbg mice. Their F? hybrids built burrow systems more complex than either parental strain. The same pattern of genetic influence was observed in an outdoor pen. In an escape task that required digging, BALB/c mice escaped more quickly than did C57BL/6 mice; their F? hybrids showed dominance toward the BALB/c phenotype. Results indicate that behavioral polymorphisms in digging behavior, which may relate to habitat selection, have a genetic basis. The dominance and overdominance toward the better digging parental strain in each type of task suggest the possible evolutionary importance of these digging behaviors. (18 ref) ?55 (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bitter avoidance in guinea pigs (Cavia porcellus) and mice (Mus musculus and Peromyscus leucopus).

Rejection of bitter substances is common in many species and may function to protect an animal from ingestion of bitter-tasting toxins. Since many plants are bitter, it has been proposed that high tolerance for bitterness would be adaptive for herbivores. Earlier studies conducted on herbivorous guinea pigs (Cavia porcellus) have been used to support this proposal. We tested guinea pigs with bitter plant secondary metabolites (salicin, caffeine, quinine hydrochloride) and bitter protein hydrolysates (two types of hydrolyzed casein, hydrolyzed soy) in a series of two-choice preference tests. For comparison, we tested two nonherbivorous mouse species (Mus musculus and Peromyscus leucopus). Guinea pigs did show weaker avoidance of quinine hydrochloride than did the mice, confirming predictions generated from earlier work. However, guinea pigs had similar responses to caffeine as did Peromyscus. Both of these species showed weaker avoidance responses than Mus to 10 mM caffeine. For salicin, guinea pigs were the only species to avoid it at 10 mM and their preference scores at this concentration were significantly lower than for the two mice species. Guinea pigs avoided all of the protein hydrolysates more strongly than the other species. Responses to the protein hydrolysates did not reflect the patterns observed with the simple bitter compounds, suggesting that other properties of these complex stimuli may be responsible for guinea pig avoidance of them. Our results suggest caution in accepting, without further empirical support, the premise that guinea pigs (and herbivores in general) have a generalized reduced bitter sensitivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal behavior, paternal behavior, and pup survival in CD-1 albino mice (Mus musculus) in three different housing conditions.

Parental behavior, food consumption, and pup development in litters of CD-1 albino mice (Mus musculus) with single mothers or paired mothers in 3 different housing conditions were compared. Fewer pups survived when parents were required to run in a wheel to obtain food, and these pups had lower weights than pups in the wheel-noncontingent and no-wheel groups. The presence of the male facilitated pup survival in the wheel-contingent group but had no effect on pup growth. Mice in the wheel-contingent group ran more revolutions than those in the wheel-noncontingent group and spent less time in parental care. In the wheel-contingent group, males spent more time running and ate less food than females, suggesting that males may indirectly facilitate pup development by providing food for the mother. The results suggest that the presence of the male increases pup care and may facilitate maternal behavior under appropriate environmental conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are there preexisting behavioral characteristics that predict the dominant status of male NIH Swiss mice (Mus musculus)?

The behavior of isolated Cr:NIH(S) mice was studied in a holeboard test of exploration, in a plus-maze test of anxiety, in the resident–intruder paradigm of aggression, and in the swim test. Thereafter, mice that were matched for body weight were housed together in groups of 4–5. Within a wk, 1 mouse per cage (the alpha) had attacked all its subordinate cagemates but lacked any signs of attack itself. Subordinate mice had bite marks on their tails and backs. When mice were isolated, no differences were found between the behavior of those that later became alphas and those that became subordinates. In contrast, after the establishment of the social hierarchy, alpha mice spent less time immobile in the swim test and had higher locomotor activities than did the subordinate mice. The results suggest that the differences in behavior between the alpha and subordinate mice result from aggressive social interactions in the home cage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of early auditory stimulation on the choice of acoustical environment by adult Swiss albino mice (Mus musculus).

In 2 experiments, 265 Swiss albino Rb-3 9-wk-old untreated mice, when placed in a novel environment composed of a central cage surrounded by 4 dark boxes in which different sounds were emitted, explored the boxes for 1 or 2 hrs. In most cases, Ss settled into 1 of the 4 boxes and built their nest. Most of the controls chose the silent compartment, whatever the sound delivered in the other boxes. An acoustic choice test was then carried out. Four groups of mice were exposed to a particular sound for 10 days: Group 1: Gestation Day 10 to birth; Group 2: birth to Day 10; Group 3: Day 10 to Day 20; Group 4: Day 20 to Day 30. Ss were then tested for box preference on Day 63 in the 4-box choice, one of which contained the sound of the earlier exposure. Ss stimulated before the 10th day after birth behaved in the same way as controls, whereas Ss stimulated between the 10th and the 20th days after birth exhibited a strong preference for the box delivering the sound of the previous treatment. This choice was significant, whatever the harmonic (Exp I) or impulsive (Exp II) nature of the sound. Ss stimulated between the 20th and the 30th days showed a preference for the silent box, but among the others, 75% chose the sound received during infancy. The behavior of Ss stimulated when adult was the same as that of the controls. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Urinary chemosignals from mice (Mus musculus): Acceleration and delay of puberty in related and unrelated young females.

Conducted 5 experiments (N?=?576) to determine the possible differential effects that urinary chemosignals from genetically related and unrelated donors have on puberty onset in female mice. The 1st 4 experiments (n?=?495), with a laboratory mouse strain, demonstrated no differential acceleration or delay of sexual maturation, with respect to a close genetic relation between donors and recipients, due to the chemosignals from estrous, diestrous, pregnant, or lactating females or grouped females. In the last experiment, wild stock Mus were used; all of the results were comparable to those found in laboratory stocks. There were no instances of differential acceleration or delay based on close genetic relatedness of donors and recipients. Results conform with a general hypothesis that the urinary chemosignals in mice communicate information about the adequacy of reproductive conditions to conspecifics. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Housing pregnant mice (Mus musculus) in small groups facilitates the development of odor-based homing in offspring.

Infant mice (Mus musculus) born to dams housed in isolation throughout pregnancy (IsoPreg) begin differentially approaching homenest bedding over clean bedding on Postnatal Day 6. Offspring of dams housed with 2 other potentially pregnant conspecifics (SocPreg) display such homing behavior on Day 4. Earlier onset of homing reflects facilitated olfactory responsiveness in SocPreg pups, rather than qualitative or quantitative differences in IsoPreg versus SocPreg nest odors, body growth, or motoric capabilities. Exposing pregnant IsoPreg dams to SocPreg bedding also accelerated homing onset in the offspring, though not to the same extent as the full social context. Thus, it appears that the facilitation of homing is mediated through the pregnant dam by a combination of chemical cues and other social stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal separation alters social odor preference development in infant mice (Mus musculus).

This study examined whether daily periods of maternal separation during the first two weeks of life would decrease attraction to familiar nest odors in CD-1 mice 10 and 14 days old. We also investigated whether placing a group of mice (Mus musculus) in nest shavings during the 180-min separation period would mitigate possible separation-induced deficits. The maternal separation procedure has been widely used as a rodent model for the effects of inconsistent or inadequate early caretaking on human development. From postnatal day (PND) 1 to 14, litters were separated from the dam, but not littermates for either 15 or 180 min, or were facility-reared controls. Control, facility-reared mice preferred home-cage nest to clean familiar shaving odors on PND 10, but not PND 14. In contrast, home-cage nest odors attracted maternally separated mice on both test days. Our results suggest that maternal separation maintains the olfactory tether to the nest in a period when the attraction normally begins to weaken. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elicitation of male mouse (Mus musculus) ultrasonic vocalizations: I. Urinary cues.

18 experiments on a total of 223 DBA/2J, AKD2F1/J, and hybrid mice, plus additional social-experience mice, examined the physical characteristics and physiological modulation of the ultrasound-eliciting property of female urine. The following results were found: An excitatory factor exists in female urine, and male urine is essentially neutral with regard to ultrasound elicitation. The ultrasound-eliciting factor is relatively nonvolatile and heat resistant, although extreme heat will destroy its activity. Ovarian and adrenal hormones appear relatively unimportant. Exogenous androgen suppresses female urinary ultrasound-eliciting activity. Castration of males did not improve the ability of their adult urine to elicit ultrasounds, nor did administration of androgen to neonatal females suppress the ability of their adult urine to elicit ultrasounds. Hypophysectomy eliminates the ultrasound-eliciting properties of female urine, which suggests that the dimorphism in ultrasound elicitation may be regulated by pituitary hormones. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of infanticide and onset of paternal care in male mice (Mus musculus).

In 7 experiments, using 331 male mice, unmated males tended to be infanticidal toward test pups. However, between mating and the birth of their litter, males stopped killing and became paternal toward test pups. Both the act of copulation and postmating cohabitation with the female influenced this onset of paternal care. The magnitude of the effect of copulation was markedly influenced by prior social experiences. However, just 1 day of cohabitation after mating had the effect of reducing infanticidal tendencies and increasing paternal responses. The timing of this effect coincided with changes in the agonistic interactions between the sexes and apparent changes in dominance/subordinancy relations. The overall effect was a complete inhibition of infanticide that allowed the onset of paternal care. Findings are discussed in relation to those of a previous study by the present author and M. C. Ostermeyer (see record 1985-00491-001), particularly with regard to the hypothesis that the reduction in infanticide may reflect subordination of males to females after mating. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)