Early visual function in bobwhite and Japanese quail embryos as reflected by pupillary reflex.

Investigated function within the visual system of 72 bobwhite and 60 Japanese quail embryos (Colinus virginianus and Coturnix coturnix) by the pupillary light reflex technique. The reflex was first reliably elicited on Day 151/2 (60% of total incubation) in Colinus and on Day 111/2 (72% of total incubation) in Coturnix. Temporal onset of visual function, as reflected by this measure, corresponded closely to that found in Peking duck embryos but was 15-18% earlier than in domestic chicks. In assessing the possible significance of early visual function, it was found that light intensities reaching the Ss in ovo were sufficient to elicit pupillary reflexes by Day 161/2 in Colinus and Day 13 in Coturnix. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biochemistry and genetics of thiodicarb resistance in the house fly (Diptera: Muscidae)

We have recently reported that environmental toxicants, such as DDT, PCBs, pyrethroids, and nicotine can induce permanent functional and neurochemical changes in adult mice when given to neonatal mice during the peak of rapid brain growth. In the present investigation the neurotoxic effects following neonatal exposure to paraquat (N,N'-dimethyl-4,4'-bipyridylium), a broad-spectrum herbicide with structural similarity to the 1-methyl-4-phenylpyridium ion (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which can induce Parkinson's syndrome, and MPTP were studied. Five groups of mice were given paraquat or MPTP orally: group 1, vehicle; groups 2 and 3, MPTP 0.3 and 20 mg/kg; groups 4 and 5, paraquat 0.07 and 0.36 mg/kg when 10 and 11 days old. Neonatal spontaneous motor activity was tested on Day 18 in mice given paraquat 0.36 mg/kg body wt. Adult spontaneous motor activity testing was performed at ages 60 and 120 days. On Day 125 the mice were decapitated and the contents of dopamine (DA), serotonin (5-HT), and metabolites in striatum were analyzed. The results may be summarized as follows: (1) No signs of acute toxicity or differences in weight gain were observed in any of the groups. Nor was any respiratory distress or motor performance dysfunction evident on Day 18 in mice given paraquat 0.36 mg/kg body wt. (2) The behavioral tests at 60 days of age showed a marked hypoactive condition in the mice given paraquat (at both doses) and MPTP (at both doses). (3) At the age of 120 days the hypoactive behavior persisted and appeared even more pronounced. (4) The high doses of MPTP and paraquat--and to a less extent the low doses--reduced the striatal content of DA and metabolites without affecting 5-HT. The altered behavior, together with the dose-dependent reduction of DA and metabolites in neostriata in this study, further demonstrates the susceptibility to low-dose exposure to environmental pollutants during the neonatal period.     

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)     

Evidence for genetic correlation of hypnotic effects and cerebellar Purkinje neuron depression in response to ethanol in mice

In the present study, we compared phenotypic differences in behavioral and neurophysiological responses to acute ethanol administration among eight inbred strains of mice. Genetic variation for behavioral sedation, as measured by loss of the righting reflex (sleep time) after a hypnotic dose of ethanol, was shown to be present among the inbred strain population. In addition, a large genetic component of variation in the depressant action of ethanol on the spontaneous discharge of cerebellar Purkinje neurons was found. Results from an analysis of covariance of the behavioral and electrophysiological phenotypes, measured on each mouse among the inbred strains, provided strong evidence for a high genetic correlation between sleep time and inhibition of cerebellar Purkinje neuron discharge in response to acute ethanol administration. Taken together with our previously reported data on ethanol-induced electrophysiological changes in selectively bred lines, the results described here strongly support the hypothesis that the cerebellar Purkinje neuron is one important locus for the acute soporific effects of alcohol.     

Comparison of Operant Escape and Innate Reflex Responses to Nociceptive Skin Temperatures Produced by Heat and Cold Stimulation of Rats.

In behavioral tests, rats performed learned escape responses to thermal stimulation of the paws by 44.0. 47.0. or 0.3 degrees C. Licking, guarding, and jumping reflexes were evaluated at these temperatures. The frequency, latency, and duration of escape and reflex responses were compared and were related to hind-paw skin temperatures measured during stimulation of awake and anesthetized rats. The duration and latency of escape from heat were appropriately related to stimulus intensity. Escape occurred reliably for each intensity. Reflexes occurred unreliably and at long latency to 44.0 or 0.3 degrees C and were not appropriately related to heat intensity. The reflexes were relatively insensitive to thermal nociceptive stimulation other than heating of the skin at a high rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early behavioral development in the spontaneously hypertensive rat: A comparison with the Wistar-Kyoto and Sprague-Dawley strains.

The spontaneously hypertensive rat (SHR) is often used as a model for childhood attention-deficit/ hyperactivity disorder (ADHD). To investigate behavioral maturation in SHR, body weight, age at eye opening, and performance in several behavioral tasks in male and female SHR, Wistar-Kyoto (WKY), and Sprague-Dawley rats were compared. SHRs were slower in performing the righting reflex on PND 4 and negative geotaxis compared with WKY and Sprague-Dawley. Both SHR and WKY were delayed relative to Sprague-Dawley in eye opening and beam walking. Rotarod performance was comparable in the 3 strains. Males were faster to right themselves than females, but there were no other significant sex differences nor Sex × Strain interactions. Delayed development in SHR may be related to a maturational delay observed in children with ADHD. Research assessing early behaviors in SHR, WKY, and other strains will help determine the most appropriate model for childhood ADHD and may help predict later behavioral dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of prosthetic superstructure accuracy on the osteointegrated implant bone interface

OBJECTIVE: To compare the behavior of macrosomic newborns who were vaginally delivered of healthy mothers without diabetes with that of non-macrosomic, appropriate-for-gestational-age (AGA) newborns. DESIGN/SETTING: Newborns were recruited conveniently from a tertiary hospital. Newborns were examined at 12-24 and 36-48 hours of age, using the Brazelton Neonatal Behavioral Assessment Scale (NBAS). PARTICIPANTS: Thirty macrosomic newborns who were delivered vaginally were matched with AGA newborns for ethnicity, maternal education, parity, and obstetric medications. MAIN OUTCOME MEASURES: Dimensions scores derived from the individual NBAS items measured reflex functioning, response decrement, orientation, motor processes, range of state, autonomic stability, and regulation of state. RESULTS: Macrosomic newborns performed weaker than AGA newborns on the reflex and motor dimensions. Both groups displayed improved motor scores on Day 2, but regulation of state scores were weaker. For orientation, AGA newborns scored higher on Day 1, and macrosomic newborns scored higher on Day 2. CONCLUSIONS: Increased head, limb, and body mass of macrosomic newborns, compared with adjacent and overall muscle strength, might have interfered with the execution of coordinated movements. Nurses can inform mothers of changes they can expect in their newborns' behavior.     

Stressor-provoked behavioral changes in six strains of mice.

Behavioral changes induced by inescapable shock were examined in 6 strains of mice. Exposure to shock provoked time-dependent disturbances of shuttle escape performance. In some strains the shock treatment did not affect escape performance, whereas in others profound performance deficits were evident. The inescapable shock treatment induced strain-dependent alterations of performance in a forced-swim task. In most instances the shock treatment initially provoked invigorated responding, but in other strains the shock had no effect or depressed active responding. Y-maze spontaneous alteration performance was not affected by the shock treatment, although a strain-dependent increase of perseverative responses was evident. The occurrence of a stressor-induced deficit in 1 task in a particular strain was not predictive of behavioral alterations in a 2nd task. Data are discussed with respect to animal models of depression and genetic differences associated with response to stressors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral heterosis: Food competition in mice.

Demonstrated hybrid vigor and behavioral homeostasis for food-competition behavior. Using female mice from 2 inbred strains (AKR/J and DBA/2J) and their F1 hybrids, 80 pairs were formed so within- and between-genotype competition could be measured. Genetic factors were major determinants of competition performance, although body weight and training time were not. It is suggested that genetically determined differences in social behavior such as food competition could affect evolutionary processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensitivity to ethanol in inbred mice: Genotypic correlations among several behavioral responses.

Assessed the sensitivity of 20 inbred strains of mice for ethanol's effects on activity, body temperature, ataxia, balance, and the righting reflex. Genotypic correlations among the mean responses for the strains were estimated as indices of pleiotropic influences of genes on drug responses. Three major groups of genetic influence were detected: (a) hypothermic sensitivity to ethanol, (b) activity change, and (c) high basal activity. In the 1st group of variables, strains that had large reductions in body temperature after being given ethanol had high baseline temperatures, a pronounced ataxic response to ethanol, and a long-lasting loss of righting reflex. The 2nd group was composed largely of ethanol-induced increases and decreases in activity. Strains with larger increases in activity showed more rapid loss of balance after ethanol. The 3rd group indicated that high levels of basal activity in an open field and in the home cage were determined by the action of common genes. Strains with higher basal activity levels had reduced sensitivity to ambulatory ataxia following ethanol. Thus, there were substantial pleiotropic effects of common genes on several behavioral responses to ethanol. Conversely, the 3 major groups were not systematically correlated with one another to a major extent. This suggests the influence of 3 reasonably distinct sets of genes on these responses to ethanol. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adapting reflexes controlling the human posture

Doubt about the role of stretch reflexes in movement and posture control has remained in part because the questions of reflex "usefulness" and the postural "set" have not been adequately considered in the design of experimental paradigms. The intent of this study was to discover the stabilizing role of stretch reflexes acting upon the ankle musculature while human subjects performed stance tasks requiring several different postural "sets". Task specific differences of reflex function were investigated by experiments in which the role of stretch reflexes to stabilize sway doing stance could be altered to be useful, of no use, or inappropriate. Because the system has available a number of alternate inputs to posture (e.g., vestibular and visual), stretch reflex responses were in themselves not necessary to prevent a loss of balance. Nevertheless, 5 out of 12 subjects in this study used long-latency (120 msec) stretch reflexes to help reduce postural sway. Following an unexpected change in the usefulness of stretch reflexes, the 5 subjects progressively altered reflex gain during the succeeding 3-5 trials. Adaptive changes in gain were always in the sense to reduce sway, and therefore could be attenuating or facilitating the reflex response. Comparing subjects using the reflex with those not during so, stretch reflex control resulted in less swaying when the task conditions were unchanging. However, the 5 subjects using reflex controls oftentimes swayed more during the first 3-5 trials after a change, when inappropriate responses were elicited. Four patients with clinically diagnosed cerebellar deficits were studied briefly. Among the stance tasks, their performance was similar to normal in some and significantly poorer in others. Their most significant deficit appeared to be the inability to adapt long-latency reflex gain following changes in the stance task. The study concludes with a discussion of the role of stretch reflexes within a hierarchy of controls ranging from muscle stiffness up to centrally initiated responses.     

Quality of parental caregiving and security of attachment.

The assumption that qualitative differences in parental behavior are associated with attachment security was examined in a sample of 62 children (M age?=?21.5 mo) who were seen separately with their mothers and fathers. Multiple measures of parental caregiving were used, including 2 qualitative behavioral rating scales and a self-report measure of attitudes and beliefs about childrearing. Analyses of the relation between these measures and maternal and parental Strange Situation classifications of attachment security revealed effects only for mothers and only with 1 parent measure. These results add to a fairly impressive body of evidence indicating inconsistent and often weak associations between parental behavioral and attachment security. Conceptual and methodological issues relevant to the parent–attachment association were identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Light-dark variation and changes across the lactational period in the behaviors of undisturbed mother and infant guinea pigs (Cavia porcellus).

Lactating guinea pigs (Cavia porcellus) and their litters were observed by videophotography across the light/dark cycle at 1, 11, 21, and 31 days postpartum. The highest level of behavioral activity was seen in the dark, particularly in the hour after light offset. This circadian pattern was evident from Day 1 in mothers and from Day 11 in pups. Contact between mothers and pups was inversely related to activity, occurring more frequently during light. Maternal grooming of pups occurred on Day 1 and then declined; self-grooming by pups increased across days. Intake of solid food and water by pups occurred on Day 1 and increased thereafter. A nearly complete transition from nursing to independent ingestion was observed between 21–31 days of age. Overall, we document several ontogenetic changes in young guinea pigs and demonstrate that under laboratory conditions mother and infant guinea pigs exhibit a nocturnal activity pattern. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between dishabituation, sensitization, and inhibition of the gill- and siphon-withdrawal reflex in Aplysia californica: Effects of response measure, test time, and training stimulus.

Previous studies have raised questions about the relationships between habituation, dishabituation, sensitization, and inhibition of reflex responses. To explore this issue further, a systematic study of these simple forms of learning was carried out in unrestrained Aplysia in which the amplitude as well as the duration of both the gill- and siphon-withdrawal reflexes were measured after either tailshock or mantle shock. The results suggest that transient reflex inhibition is not an invariant effect of noxious stimulation but depends instead on the response measure, test time, and type of noxious stimulus. Furthermore, the results suggest that dishabituation and sensitization may not involve different processes at the behavioral level; rather the observed differences between them may be due largely to an interaction between habituation and inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differences in the liability to self-administer intravenous cocaine between C57BL/6 x SJL and BALB/cByJ mice

Application of animal models of psychostimulant abuse for experimentation in mice is becoming increasingly important for studying the contribution of genetic differences, as well as the roles of selected (targeted) genes, in specific behaviors. The purpose of this study was to investigate strain differences in cocaine self-administration behavior between C57BL/6 x SJL hybrid mice and BALB/cByJ mice. These two strains were chosen because BALB/cByJ mice have a well-developed behavioral pharmacological profile, and hybrid strains on a C57BL/6 background are commonly used for generating transgenic expressing and knockout mutant mice. C57BL/6 x SJL mice dose-dependently acquired cocaine self-administration (1.0 mg/kg/injection but not 0.25 mg/kg/injection) by responding selectively in the active nose-poke hole and maintaining stable levels of daily drug intake; they also exhibited a characteristic inverted-U-shaped cocaine dose-effect function. BALB/cByJ mice failed to acquire cocaine self-administration at either dose under the same test conditions. The strain differences observed in self-administration did not seem to be attributed to other behavioral differences because the two strains exhibited similar amounts of spontaneous nose-poking in the absence of reinforcers, and BALB/cByJ mice responded more than C57BL/6 x SJL mice in a food-reinforced nose-poke operant task. Importantly, the dose-effect function for the motor stimulating effects of cocaine (3.8-30 mg/kg intraperitoneally) suggests enhanced sensitivity but reduced efficacy of cocaine in stimulating motor activity in BALB/cByJ mice relative to the C57BL/6 x SJL hybrid mice. These results indicate that the decreased liability of BALB/cByJ mice to acquire cocaine self-administration is not the result of differences in spontaneous activity or performance, but may reflect different sensitivities to the reinforcing, or rate-disrupting, properties of cocaine. The data support an influence of genetic background in the liability to self-administer cocaine. Thus, a hypothesis is proposed that the decreased liability of BALB/cByJ mice to acquire cocaine self-administration is related to differences in brain monoamine systems linked to the high "emotionality" profile of BALB/c mice in novel or fearful situations, including perhaps cocaine administration.     

Electrophysiological responses to ethanol, pentobarbital, and nicotine in mice genetically selected for differential sensitivity to ethanol.

Examined cortical EEG changes induced by ethanol (4.3 and 1.4 g/kg, ip), pentobarbital (50 and 16 mg/kg), and nicotine (1.0 g/kg) in long-sleep (LS) and short-sleep (SS) male mice that were genetically selected for differential sleep times induced by a hypnotic dosage of ethanol. Ethanol (4.3 g/kg) caused EEG changes that paralleled the behavioral differences, whereas no differences between selected lines were observed following the activating dose (1.4 g/kg). Data support the notion that the known difference in ethanol sleep times is due not to greater SS sensitivity to ethanol activation but rather to greater LS sensitivity to ethanol hypnosis. No differences between selected lines were observed following 50 mg/kg pentobarbitol, which again parallels previous behavioral data. SS mice were more responsive to pentobarbital activation (16 mg/kg). Nicotine more severely reduced EEG power and heart rate in LS Ss; a continuous infusion of nicotine elicited a distinct pattern of behavioral stereotypy for each selected line, with more profound motor and reflex depression in LS Ss. The lines do not differ in rate of nicotine metabolism, hence they must differ in CNS sensitivity to nicotine. Thus, mice selectively bred for differential sensitivity to ethanol also differ in electrophysiological and behavioral responses to nicotine. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of neonatal RU486 on adult sexual, parental, and fearful behaviors in rats.

Exposure to gonadal hormones during perinatal life influences later behavior. The finding that sex differences exist in progestin receptor expression in the perinatal rat brain suggests differential sensitivity of male and female brains to progesterone (C. K. Wagner, A. N. Nakayama, & G. J. De Vries, 1998). Because these sex differences are in neural sites that influence sexually differentiated sexual, parental, and fearful behaviors in adults, this study examined the effects of administering the progestin receptor antagonist RU486 for the first 10 days after birth on these behaviors in adulthood. Neonatal RU486 significantly reduced sexual behavior in males but did not impair reproduction in females. Neonatal RU486 did not affect parental responses of virgin rats exposed to pups (sensitization) but reduced fear in the elevated plus-maze in both sexes. Treatment of pups with RU486 affected neither mother–litter interactions nor plasma testosterone levels in males during or after treatment. These results suggest that neonatal exposure to progesterone, in addition to androgens and estrogens, influences behavioral development in rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction of cardiopulmonary and somatic reflexes in humans

Activation of cardiopulmonary receptors with vagal afferents results predominantly in reflex inhibition of efferent sympathetic activity, whereas activation of somatic receptors reflexly increases sympathetic activity to the heart and circulation. Previous studies in experimental animals indicate that there is an important interaction between these excitatory and inhibitory reflexes in the control of the renal circulation. The purpose of this study was to determine whether there is a similar interaction between somatic and cardiopulmonary reflexes in humans. The activity of the cardiopulmonary receptors was altered (reduced) with lower body negative pressure (-5 mm Hg), which causes a decrease in cardiac filling pressure and a small reflex increase in forearm vascular resistance without accompanying changes in arterial pressure. Activation of somatic receptors by isometric handgrip for 2 min at 10 and 20% of maximum voluntary contraction resulted in reflex vasoconstriction in the nonexercising arm. Lower body negative pressure at -5 mm Hg produced a threefold augmentation in the forearm vasoconstrictor response to isometric handgrip in the nonexercising arm. This increase in resistance was significantly greater (P < 0.05) than the algebraic sum of the increases in resistance resulting from lower body suction alone plus isometric handgrip alone. Furthermore, it occurred despite a greater rise in arterial pressure, which would be expected to decrease forearm vascular resistance through activation of arterial baroreceptors and through passive dilatation of forearm vessels. Thus, removal of the inhibitory influence of cardiopulmonary receptors by pooling blood in the lower extremities enhances the somatic reflex. These data suggest an interaction between cardiopulmonary and somatic reflexes in the control of forearm vascular resistance in man.     

Effects of genetic vestibular defects on behavior related to spatial orientation and emotionality.

Administered a large battery of behavioral tests to 11 normal mice and to 20 mice with varying degrees of otoconial agenesis due to genes affecting vestibular development. Many significant differences were found, but a factor analysis revealed that the variance on the 11 best tests could be accounted for in terms of 2 underlying variables. Factor I, the more important of the 2, was associated with activity, habituation, and spontaneous alternation. Factor II appeared to represent a fear of new stimuli or situations. In both cases, factor scores were highly related to the degree of otoconial deficiency. In a 2nd experiment, a subgroup of 5 Ss with severe otoconial agenesis displayed hyperactivity and a total absence of either habituation or spontaneous alternation. In these Ss brain and body development were stunted, and the reactions to amphetamine and physostigmine were opposite to those seen in normal Ss. Results support the idea that the static organs contribute importantly to spatial orientation and suggest that early-onset vestibular defects can result in profound alterations of emotionality. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neonatal handling alters brain organization but does not influence recovery from perinatal cortical injury.

Handling rat pups by removing them from the nest during the preweaning period has been shown to influence brain and behavioral development. The authors hypothesized that handling rats with perinatal (Day 4) medial frontal cortex removals might attenuate behavioral deficits and reverse dendritic atrophy associated with such an injury. On the day after surgery, pups were removed from the nest for 15 min, 3 times per day until weaning. Animals were tested as adults in the Morris water task and on skilled reaching. Handled animals showed no improvement in behavioral performance. The handling procedure led to a decrease in dendritic length in parietal cortex, but spine density was unchanged. No therapeutic advantage was observed following the preweaning handling of brain-injured rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)