Combined dieting and stress evoke exaggerated responses to opioids in binge-eating rats.

The authors developed an animal model of binge eating where history of caloric restriction with footshock stress (R + S) causes rats to consume twice the normal amount of palatable food. The authors tested the hypothesis that binge eating is mediated by changes in opioid control of feeding by comparing rats' anorectic and orexigenic responses to naloxone and butorphanol, respectively, and by testing the ability of butorphanol to elicit binge eating of chow when palatable food was absent. Mu/kappa opioid-receptor blockade and activation had exaggerated responses in the R + S rats with naloxone suppressing binge eating to control levels, and although butorphanol did not trigger chow binge eating, it enhanced binge eating of palatable food. These responses in sated normal-weight rats strengthen evidence that reward, over metabolic need, drives binge eating. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiac and behavioral responses to repeated tactile and auditory stimulation by preterm and term neonates.

Auditory stimuli (a buzzer and rattle) and a tactile stimulus (a plastic filament) were repeatedly presented to 18 term and 18 preterm infants. Both groups initially responded to all stimuli with increased limb movements and heart rate acceleration. However, only the term infants responded to stimulus repetition by decreasing both cardiac and behavioral responses. In addition, they differentially responded to the 3 stimuli and showed response recovery in both systems. Since a behavioral response decrement was observed without a cardiac response decrement in the preterm group, a 2nd experiment was conducted. Heart rate change during the sucking activity of Exp II revealed an integration between autonomic and motor responsivity of preterm infants comparable to that of term newborns. The lack of cardiac–behavioral response integration during Exp I is discussed in the context of state differences between preterm and term infants as well as potential immaturity or some insult experienced by the preterm infants. The stimulus discrimination and habituation demands of Exp I may have overtaxed the preterm infants' ability to maintain response integration. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological and behavioral reactivity to photic stimuli following septal lesions and pharmacological treatments in rats.

Conducted 4 experiments, with a total of 86 male Holtzman albino rats, which investigated behavioral reactivity and cortical visual evoked response (VER) to photic stimulation. Analysis revealed 2 patterns of lesion-induced changes. One pattern of VERs reflected a hypoarousal electrophysiological condition. This pattern, present initially under all conditions, could be simulated with administration of scopolamine. A 2nd pattern of VERs developed gradually and appeared to reflect a hyperaroused electrophysiological condition. This pattern could be simulated with dextroamphetamine. While both lesion-induced electrophysiological patterns were associated with augmented behavioral reactivity to flashes, the hyperarousal pattern related to more intense conditions of stimulation and more sustained behavioral reactivity. Scopolamine, as opposed to dextroamphetamine, reproduced the heightened behavioral reactivity to the flashes. Results are interpreted in terms of a hypoarousal hypothesis of sensory hyperreactivity. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attributions as moderators of affective and behavioral responses to social failure.

Undergraduate women with a helpless or nonhelpless attributional style as measured by the Attributional Style Questionnaire were subjected to social failure or success (interaction with unresponsive or responsive confederates). Subsequently, each interacted with a second naive subject. As predicted, individuals with a helpless attributional style became depressed and hostile (as measured by the Multiple Affect Adjective Check List) after interacting with an unresponsive confederate. Furthermore, in comparison with nonhelpless subjects, helpless subjects who interacted with the unresponsive confederate evidenced more tension in their voices during both interactions and less pleasantness in their nonverbal behavior during the second interaction. Overall, the second group of subjects did not respond differently to the first group of subjects as an interactive function of attributions and experimental condition of the initial subjects. However, helpless subjects in the second group spoke less, were less nonverbally pleasant, and became more hostile than did nonhelpless subjects after interacting with individuals who had previously interacted with an unresponsive confederate. A consistent but unexpected pattern was found for nonhelpless subjects: They responded more adaptively to stressful than to nonstressful interactions. Results are interpreted as providing support for a vulnerability model of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A behavioral and pharmacological analysis of variables mediating active-avoidance behavior in rats.

In Exp. I, two strains of rats (F344 and ZM) were run in a discriminated -maze avoidance task. The F344s were greatly superior to ZMs in acquiring the avoidance response although both strains learned the discrimination. Analysis of other response measures indicates that F344s made significantly more active responses, suggesting that differences in avoidance behavior were due to strain-specific differences in the unconditioned response to shock. In Exp. II, the same Ss were administered d-amphetamine, scopolamine, or a combination of the 2 drugs. These manipulations significantly improved avoidance behavior in the ZM strain and increased other active responses. Results suggest that the prepotent variable in active-avoidance acquisition is the extent to which the S's response to shock is compatible with the response required. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partitioning environmental and genetic contributions to behavioral development.

Model-fitting methods are described for estimating genetic and environmental contributions to the variation of behavioral traits. These methods are illustrated by application to data from recent large twin studies of neuroticism and extraversion and to summary data on IQ. Some possible environmental and genetic implications of the results are considered. The environmental implications of these analyses may be of even more interest to psychologists than the genetic ones. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ingestive responses to homeostatic challenges in rats with ablations of the anterolateral neocortex.

Because rats with either anterolateral neocortical (AN) or lateral hypothalamic (LH) damage initially display similar feeding and drinking deficits and recovery patterns, the present study examined the possibility that anterolateral neocortical ablations would also produce similar chronic ingestive impairments to glucoprivic and hydrational challenges. 73 male Sprague-Dawley rats received AN or dorsoposterior neocortical lesions or served as unoperated controls. Ss with AN ablations exhibited normal feeding responses to food deprivation and glucoprivation induced by insulin (4–26 U/kg, sc) or 2-deoxydextroglucose (2-DG [125 or 250 mg/kg, ip]), but their response to 500 mg/kg or 2-DG was impaired. These Ss also drank normally in response to hypertonic saline injections and following water deprivation but only if food was available during the test session. Results indicate that, although the anterolateral neocortex and LH are anatomically related, these brain regions appear to be functionally dissimilar in terms of the regulation of ingestion. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Day-night variations of behavioral and autonomic thermoregulatory responses to lipopolysaccharide in rats

This study investigated the day-night differences in behavioral and autonomic thermoregulatory responses to bacterial lipopolysaccharide (LPS) in rats. Male rats were housed individually in cages with a 12: 12 h light dark cycle at an ambient temperature of 24 degrees C. The rats were placed in a box with a temperature gradient and intraperitoneally injected with LPS (10 micrograms/kg). The preferred ambient temperature (Tpr) was estimated by the location of the rats in the box, and intraperitoneal temperature (Tb) was measured by a biotelemetry system. Measurements were taken during the light and dark phases of the day. LPS produced fever in both phases. The magnitude of rise in Tb did not differ between the two periods. In the dark phase, Tpr significantly increased during the development of fever and decreased during the defervescence, while it did not change throughout the febrile course during the light phase. In a separate experiment, rats were loosely restrained and placed in a direct calorimeter. Their colonic temperature (Tcol), evaporative and nonevaporative heat loss and heat production were measured before and after intraperitoneal injections of LPS (10 micrograms/kg). Measurements were taken during the light and dark phases of the day. LPS induced fever in both phases. The magnitude of change in T col, heat loss, and heat production due to LPS did not differ between the two periods. These results suggest that the fertile response of rats to intraperitoneal LPS is not affected by the time of day. However, it seems that during LPS-induced fever, thermoregulatory behavior is not fully activated during the light phase of the day.     

The ontogeny of feeding in rats: I. Ingestive and behavioral responses to oral infusions.

Reports on 3 experiments with Charles River rat pups. When milk infusions were made through oral cannulas in the front of their mouths, 1–20 day old Ss actively ingested the diet, and their intake was related to the length of deprivation. Ss decreased their ingestive responding after they had consumed large volumes of milk. In addition, 1-, 3-, and 6-day-old Ss, when 24-hr deprived, exhibited an intense behavioral activation in response to milk infusion. The behavioral activation appeared to be stimulated primarily by taste and the opportunity to swallow. Milk infusions did not produce activation in older Ss; their behavior was more exclusively ingestive and food directed. Results demonstrate that (a) from birth, rat pups are capable of an active form of ingestion, independent of normal suckling from the mother; (b) such ingestion is controlled by physiological factors; (c) food has arousing properties in young animals; and (d) as pups grow older, their ingestive responding is refined from a generalized and nondirected activation to specific and directed feeding responses. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiovascular and neurohumoral responses to behavioral challenge as a function of race and sex.

Cardiovascular and hormonal responses to a structured interview, an electronic video game, a cold pressor test, and exercise on a bicycle ergometer were assessed in 83 normotensive Black and White men and women (aged 25–44 yrs). Black Ss showed significantly greater diastolic blood pressure (DBP) responses than White Ss during the cold pressor test, which were not accounted for by an increase in plasma catecholamines. Exercise produced reliably greater systolic blood pressure (SBP) increases in Black women than in Black men or White women. Men showed significantly greater SBP and DBP changes than women during the video game. The pattern of physiological reactivity elicited by challenge may be related to the Ss' race and sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional and behavioral responses to aversive interpersonal behaviors.

In a conceptual replication of A. Biglan et al (see record 1989-39898-001), 288 Ss rated their emotional and behavioral responses to aggressive, distressed, and neutral behaviors. The stimulus behaviors occurred in the context of casual relationships and were portrayed by male and female actors. Consistent with Biglan et al, it was found that aggressive behaviors evoked angry emotions and negative behavioral responses; distressed behaviors evoked both angry and concerned emotions and supportive behavioral responses. However, in contrast to the original results, evidence was also found of negative (primarily avoidant) behavioral responses to distressed behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective and behavioral responses to health-related social control.

Social control has the potential to encourage engagement in a healthy lifestyle, but its effectiveness may depend on the nature of the influence attempt. Participants (N = 282) described a situation in which someone attempted to influence their health-related behavior. Experiencing positive social control was associated with a greater tendency to change the behavior and less ignoring/doing nothing, whereas negative social control was associated with a lesser tendency to change the behavior and more hiding of unhealthy behavior. These associations could be accounted for by affective responses to the social control attempts. Results emphasize the need to better understand the regulatory influence of relationships on health behavior and the conditions under which social control is most likely to have health-promoting effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taste receptors on the anterior tongue and nasoincisor ducts of rats contribute synergistically to behavioral responses to sucrose.

In 4 groups of rats, behavioral responsiveness to sucrose was tested by allowing them to lick solutions in a computer-controlled gustometer (10-sec trials; 0.01–2.0 M). Rats with cautery lesions of the nasoincisor ducts (NID) behaved no differently from controls. After bilateral chorda tympani nerve (CT) section, which removes taste input from the anterior tongue (AT), rats demonstrated a marginal attenuation in their responsiveness to sucrose. Combining the 2 lesions, however, had the greatest effect on the concentration–response curve. By shifting the curve to the right and lowering the asymptotic licking rate, the combined lesion reduced the area under the curve by one third. The effects of the combined treatments were larger than would be predicted from the sum of either one alone. This presumably reflects the central convergence of primary afferent axons from the NID and AT. Neurophysiological data have demonstrated such convergence within the nucleus of the solitary tract. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ontogeny of feeding in rats: IV. Taste development as measured by intake and behavioral responses to oral infusions of sucrose and quinine.

Delivered infusions of sucrose or quinine through cannulas implanted in Charles River CD rat pups' mouths. Intake was measured, and behavioral responses were scored. Responsiveness to sweet and bitter tastes emerged over the 1st 2 wks of postnatal life. Pups showed discrimination between water and sucrose in their mouthing behavior and general activity from 3 days of age, but in their intake only from 6 days of age. Discrimination between water and quinine was not shown until 9 days of age in either behavior or intake. Even then, the stereotypic aversion reactions (paw treading, chin scraping) that characterize the adult response to quinine were not apparent until 12 days. By 15 days of age, preferences for sucrose and aversions to quinine were robust, resembled those of adult rats, and did not depend on previous experience with either solution. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in electrophysiological and behavioral responses to NaCl taste.

We tested the hypothesis that sex differences in preference for NaCl are attributable to estrogen-mediated alterations in gustatory processing. Electrophysiological responses of the chorda tympani nerve to NaCl were blunted by estrogen treatment in ovariectomized female rats, suggesting that females are less sensitive to concentrated NaCl solutions during high estrogen conditions. In contrast, after a taste aversion was conditioned to 150-mM NaCl, estrogen- and oil-treated ovariectomized rats generalized the aversion to a lower concentration of NaCl than did males, suggesting that females are more sensitive to the taste of dilute NaCl solutions regardless of estrogen. Thus, sex differences in NaCl preferences may be attributable to differences in NaCl taste processing that involve both acute and developmental effects of estrogen. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysiological outcome of behavioral and pharmacological treatments of agoraphobia.

62 severe and chronic agoraphobics (aged 18–65 yrs) participated in a 2?×?2 factorial investigation of the relative and combined effectiveness of behavior therapy (prolonged in vivo exposure) and pharmacotherapy (imipramine). Treatment was conducted in 12 weekly sessions. Imipramine or placebo was administered in 25-mg tablets at bed time, with 25-mg increases every 2nd day until the maximum tolerable amount was achieved. Tripartite assessments were conducted at pretreatment and at 4 wks, 8 wks, 12 wks, and 1-mo posttreatment. Differential temporal response and treatment patterns were identified across the psychophysiological domains. Ss receiving medication showed equivocal patterns of positive and negative responses. Decreases in arousal were noted with Ss who received prolonged exposure. Synchrony/desynchrony phenomena yielded significant findings with regard to both process and clinical outcome status. Exploratory analyses were performed to identify potential mediating factors in physiological outcome, and a psychophysiological comparison was also undertaken contrasting agoraphobics prior to and following treatment with normative (nonphobic) cohorts. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of ZnCl2 pretreatment on behavioral and histological responses to kainic acid in rats

Kainic acid evokes behavioral convulsions and causes lesions in hippocampal pyramidal cell layers in rats. The effects of ZnCl2 pretreatments on these events were examined. Rats were given ZnCl2 (35 mg/kg, subcutaneously (s.c.)) 15 min prior to kainic acid administration (12 mg/kg, intraperitoneally (i.p.)). Another group of animals was given an additional dose of ZnCl2 (35 mg/kg, i.p.) 24 h prior to the s.c. ZnCl2 and i.p. kainic acid. All rats that received kainic acid, whether saline controls or ZnCl2 pretreated, experienced wet dog shakes (WDS) and convulsions. No significant differences were seen between groups in number or latency of WDS or convulsions. Two days after behavioral data were collected, the brains were perfused and the extent of lesioning among hippocampal CA1 and CA3 pyramidal cells was quantified. A single dose of ZnCl2 had either no effect or a slight protective effect on cell lesioning induced by kainic acid. However, lesioning was more pronounced in animals treated twice with zinc. It is concluded that zinc, co-administered with kainic acid, augments kainate cytotoxicity when the dose and timing of zinc exposure are within a critical period.     

Early impact of a fat-enriched diet on behavioral responses of male and female rats.

Prolonged high-fat diets have been shown to affect an organism's stress responsiveness at the neuroendocrine level. In the present study, the authors used a 7-day protocol of fat administration in adult rats of both sexes to investigate the early behavioral impact of a moderately fat (20%) diet, often used by Western societies, on rats' reaction to acute stress and novelty. Their results show that this diet can reduce the rats' active behavioral responses to subsequent stressors and influence their corticosterone secretion. Fat-fed male rats adopted a less active behavior to cope with forced swimming stress, whereas their exploratory behavior in the open field environment was rather increased compared with chow-fed males. Fat-fed female rats exhibited a less active behavioral response to both stress paradigms compared with their chow-fed counterparts. Fat diet abolished facilitation in corticosterone secretion following a subsequent stressor in both sexes. However, only in males did fat diet exaggerate corticosterone response to novelty, irrespective of the previous stress history of the rat. These data indicate that a short-term metabolic stress can modify the rats' stress coping strategy in interaction with the gender. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiac and visual responses to stimuli presented both foveally and peripherally as a function of moving stimuli.

Measured heart rate (HR) and visual fixation responses as indices of attention getting (AG) and attention holding (AH) in 17 15-wk-old infants. The stimulus situation was one in which a brief central stimulus was followed by either a brief peripheral stimulus (AG trials) or a prolonged peripheral stimulus (AH trials). The stimuli for both central and peripheral presentations were moving black and white bar patterns. The speed for the central stimulus was constant over trials and groups (at 6.6°/sec), whereas the peripheral stimuli were either 6.6 or 26°/sec. Results suggest that much of the observed HR change can be accounted for by the AG phase, whereas the AH phase was reflected in the time it took for the cardiac responses to return to prestimulus baseline values. Stimulus speed also affected both attention behaviors; the faster speed produced the greatest HR change. Latency of 1st fixation and duration of looking measures did not show any discrimination between stimuli of different speeds. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of behavioral and pharmacological treatment on smokeless tobacco users.

The purpose of this study was to examine the effects of 2 mg of nicotine polacrilex versus placebo gum and of group behavioral treatment versus minimal contact on cessation of smokeless tobacco use. Participants (N?=?210) were randomly assigned 1 of the 4 treatment conditions. Withdrawal symptoms were assessed throughout the treatment. Follow-up assessments were made at 1, 6, and 12 months posttreatment. Survival curve analysis showed that any of the 3 treatment groups involving group behavioral therapy or placebo gum were equally effective and superior to the minimal contact plus 2 mg of nicotine gum treatment in terms of abstinence. On the other hand, withdrawal symptoms were significantly reduced by nicotine gum, compared with placebo during the initial phases of cessation. The ineffectiveness of nicotine gum on treatment outcome may be attributed to its similarity with smokeless tobacco. (PsycINFO Database Record (c) 2010 APA, all rights reserved)