Regional cerebral blood flow during experimental phobic fear

Positron emission tomographic measurements of regional cerebral blood flow (rCBF) were used to investigate central nervous system correlates of fear and anxiety. Volunteers with symptomatic snake phobia were studied while exposed to visual phobogenic, aversive, and neutral stimuli. Anxiety ratings and the number of nonspecific electrodermal fluctuations increased as a function of phobic stimulation. Phobic, compared to neutral and aversive, stimulation elevated rCBF in the visual associative cortex. The basal ganglia were not activated more by phobic than aversive or neutral stimulation. However, cortical and thalamic rCBF were always correlated during phobic but not aversive or neutral stimulation. This indicates that the thalamus could be a relay station for phobic stimulus processing and affect.     

Virtual reality for the psychophysiological assessment of phobic fear: Responses during virtual tunnel driving.

An overall assessment of phobic fear requires not only a verbal self-report of fear but also an assessment of behavioral and physiological responses. Virtual reality can be used to simulate realistic (phobic) situations and therefore should be useful for inducing emotions in a controlled, standardized way. Verbal and physiological fear reactions were examined in 15 highly tunnel-fearful and 15 matched control participants in 3 virtual driving scenarios: an open environment, a partially open tunnel (gallery), and a closed tunnel. Highly tunnel-fearful participants were characterized by elevated fear responses specifically during tunnel drives as reflected in verbal fear ratings, heart rate reactions, and startle responses. Heart rate and fear ratings differentiated highly tunnel-fearful from control participants with an accuracy of 88% and 93%, respectively. Results indicate that virtual environments are valuable tools for the assessment of fear reactions and should be used in future experimental research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A factor analysis of personality and fear variables in phobic disorders.

Investigated the fears and personality traits of 225 individuals (mean age 32.5 yrs) experiencing 1 of 4 phobic conditions—agoraphobia, claustrophobia, social phobia, or some other specific phobia. Several Fear Survey Schedule variables and the personality scales of the Guilford-Zimmerman Temperament Survey were factor analyzed. Five factors were extracted that were consistent with previous findings, which were related to each of 4 independent variables: Treatment Subgroup, Diagnosis, Age, and Sex. Clinic and private clients did not differ significantly on any factor, nor did age account for any meaningful change in factor scores. The diagnostic groups scored discrepantly on 2 factors: Social Activity and Cognitive Introversion, and Fear of Sensory Stimuli. Females differed significantly from males on Femininity and Miscellaneous Fears. Results are discussed in terms of past research and possible ramifications for the clinical practice of behavior therapy. (French abstract) (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive and interactive effects of stimulus degradation: No challenge for CDP+.

[Correction Notice: An erratum for this article was reported in Vol 35(2) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2009-02753-020). The URL for the supplemental material was incomplete. The complete URL is http:dx.doi.org/10.1037/a0013738.supp.] S. O'Malley and D. Besner (2008) showed that additive effects of stimulus degradation and word frequency in reading aloud occur in the presence of nonwords but not in pure word lists. They argued that this dissociation presents a major challenge to interactive computational models of reading aloud and claimed that no currently implemented model is able to simulate additive effects in these conditions. In the current article, it is shown that the connectionist dual process model (CDP+) can simulate these effects because its nonlexical route is thresholded. The authors present a series of simulations showing that CDP+ can not only simulate the precise dissociation observed by O'Malley and Besner but more generally can produce additive effects for a wide range of parameter combinations and different sets of items. The nonlexical route of CDP+ was not modified post hoc to deal with the effects of stimulus quality, but it had been thresholded for principled reasons before it was known that these effects existed. Together, the effects of stimulus quality on word frequency do not challenge CDP+ but rather provide unexpected support for its architecture and processing dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of uncertainty about the behavior of a phobic stimulus on subjects' fear reactions.

19 rat-phobic female college students were repeatedly exposed to a live rat on a nearby platform under instructional conditions designed to induce different expectancies about the probability of the rat remaining on the platform. Although the rat's behavior was the same in both conditions, Ss who were led to believe that the rat might leave the platform evidenced significantly greater cognitive and physiological arousal to repeated rat exposures than did Ss who were informed that the rat would definitely not leave the platform. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective effects of naltrexone on food pleasantness and intake

The effects of 50 mg naltrexone on both pleasantness and intake of 10 common food items were investigated using a double-blind placebo-controlled study with 16 male volunteers. Rated food pleasantness was reduced significantly in the naltrexone condition compared with both controls (placebo and baseline). However, pleasantness ratings were not affected uniformly across foods, with sweetened, fatty, and high-protein foods being most affected. Changes in rated unpleasantness generally mirrored those for pleasantness, but evaluations of saltiness and sweetness were unaffected by naltrexone. Although total intake was reduced in the naltrexone condition, this was not significant compared with placebo. However, fat and protein intakes were significantly less following naltrexone. The effect of naltrexone on intake was also food dependent, but in this case intake of sweet foods was spared relative to other food categories. The apparent discrepancy between liking and intake data with sweet foods could be interpreted in terms of the likely influence of normal eating styles on food selection during a buffet-style meal, and may explain some contradictions in previous studies of this kind. The implications for understanding opioid involvement in food acceptability are discussed.     

Primate vocalizations during social separation and aggression: effects of alcohol and benzodiazepines

The most common group of squirrel monkey vocalizations, peeps, are emitted during different social situations including social separation, affiliative interactions, feeding and aggressive confrontations. The present experiments investigated whether peeps and other vocalizations emitted during different social contexts are pharmacologically altered in a similar manner. First, vocalizations were characterized during (1) social separation in juveniles, and (2) "resident-intruder" aggressive confrontations between dominant monkeys from different social groups. Then, the effects of alcohol (EtOH) and the benzodiazepine chlordiazepoxide (CDP) on vocalizations during social separation and during aggression were examined. Isolated juveniles emitted only one type of call, the isolation peep. Resident monkeys primarily emitted peeps, but also emitted cackles, chucks, noisy calls and pulsed calls. Aggressive peeps were similar in structure and frequency (kHz) to isolation peeps, but were shorter in duration. At the same doses, both CDP (0.3-3 mg/kg) and EtOH (0.1-1.0 g/kg) reduced explosive motor behaviors and isolation peeps in juvenile monkeys during social separation and increased threat displays and aggression peeps in resident monkeys during confrontations with an intruder monkey from a different social group. Thus, similarly structured vocalizations that were emitted during social separation and aggression were very sensitive to EtOH and CDP, but the social context determined the direction and magnitude of effects.     

On the automatic nature of phobic fear: Conditioned electrodermal responses to masked fear-relevant stimuli.

Normal Ss (n?=?64) were exposed either to pictures of snakes and spiders or to pictures of flowers and mushrooms in a differential conditioning paradigm in which one of the pictures signaled an electric shock. In a subsequent extinction series, these stimuli were presented backwardly masked by another stimulus for half of the Ss, whereas the other half received nonmasked extinction. In support of a hypothesis that suggests that nonconscious information-processing mechanisms are sufficient to activate responses to fear-relevant stimuli, differential skin conductance response to masked conditioning and control stimuli was obvious only for Ss conditioned to fear-relevant stimuli. These results were replicated in a 2nd experiment (n?=?32), which also demonstrated that the effect was unaffected by which visual half-field was used for stimulus presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term effects of naltrexone in 155 heroin ex-addicts

The narcotic antagonist naltrexone was administered for periods of up to 8 months to a total of 155 patients at a dose of 40-200 mg per day. The antagonistic effect of naltrexone was tested by injections of heroin. Eighty milligrams of natrexone was effective for 48hr. The antagonistic effect decreased at 72 hr after the administration of 120-200 mg of naltrexone. Laboratory tests indicated no signs of toxicity. Naltrexone may elicit an increase in blood pressure and opigastric pain. Neither of these side effects appear clinically important. No signs of dependence on naltrexone were detected. These results suggest that naltrexone may be useful for clinical treatment of opiate dependence.     

The effects of fear arousal and suppression of fear upon social perception.

A research was designed to study the effects of fear arousal and suppression of fear upon social perception. "It was hypothesized that individuals subjected to a fear-producing situation would tend to project their feelings upon some social objects, and further, instructions to inhibit emotional reactions would increase the amount of projection." Sixty male volunteers from introductory psychology classes were randomly assigned to one of three groups: Control, Fear-Expression and Fear-Suppression. "The data indicate that the arousal of fear results in a tendency to project fear onto a stimulus object in the environment. The results are also consistent with the hypothesis that suppression facilitates the tendency to project although, in this latter instance, one is less confident in rejecting the null hypothesis. Several alternative explanations of the effects of the suppression variable were considered and the role of cognitive variables in the projection process were discussed." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using analog baselines to assess the effects of naltrexone on self-injurious behavior

Healthy male and female human volunteers were exposed to 50 ppm or 100 ppm trichloroethylene (Tri) by inhalation for 4 h. Blood and urine samples were taken at various times before, during, and after the exposure period for analysis of glutathione (GSH), related thiols and disulfides, and GSH-derived metabolites of Tri. The GSH conjugate of Tri, S-(1,2-dichlorovinyl)glutathione (DCVG), was found in the blood of all subjects from 30 min after the start of the 4-h exposure to Tri to 1 to 8 h after the end of the exposure period, depending on the dose of Tri and the sex of the subject. Male subjects exposed to 100 ppm Tri exhibited a maximal content of DCVG in the blood at 2 h after the start of the exposure of 46.1 +/- 14.2 nmol/ml (n = 8), whereas female subjects exposed to 100 ppm Tri exhibited a maximal content of DCVG in the blood at 4 h after the start of the exposure of only 13.4 /- 6.6 nmol/ml (n = 8). Pharmacokinetic analysis of blood DCVG concentrations showed that the area under the curve value was 3.4-fold greater in males than in females, while the t1/2 values for systemic clearance of DCVG were similar in the two sexes. Analysis of the distribution of individual values indicated a possible sorting, irrespective of gender, into a high- and a low-activity population, which suggests the possibility of a polymorphism. The mercapturates N-acetyl-1,2-DCVC and N-acetyl-2,2-DCVC were only observed in the urine of 1 male subject exposed to 100 ppm Tri. Higher contents of glutamate were generally found in the blood of females, but no marked differences between sexes were observed in contents of cyst(e)ine or GSH or in GSH redox status in the blood. Urinary GSH output exhibited a diurnal variation with no apparent sex- or Tri exposure-dependent differences. These results provide direct, in vivo evidence of GSH conjugation of Tri in humans exposed to Tri and demonstrate markedly higher amounts of DCVG formation in males, suggesting that their potential risk to Tri-induced renal toxicity may be greater than that of females.     

The effects of changing contexts on return of fear following exposure therapy for spider fear.

Treatment of specific fears and phobias is sometimes followed by a return of fear. Work with rats has provided evidence that a greater return of fear occurs when a conditioned stimulus extinguished in 1 context is later presented in a different context than if presented in the same context in which it was originally extinguished. In the present study. 36 human participants who were highly afraid of spiders received 1 session of exposure therapy (with participant modeling) and were then tested for return of fear 1 week later in either the same or a different context. It was hypothesized that there would be a greater return of fear in those participants treated and followed up in different contexts than in those treated and followed up in the same context. Participants tested in a novel context at follow-up showed a greater return of fear than participants tested in the same context. Limitations and areas for future study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibitory effects of naltrexone on the induction of parental behavior in juvenile rats

Juvenile rats are rapidly responsive to pups soon after weaning, displaying maternal-like behaviors such as licking, retrieving, grouping, and crouching over pups. As juveniles reach 30 days of age, they become less responsive to pups and show increased latencies to display the same parental behaviors. In light of previous data implicating opiates in the display of ongoing maternal behavior, we administered naltrexone, a long-acting opiate antagonist, beginning 5 and 9 days prior to and continuing throughout the period of behavioral testing, which started at 26 or 30 days of age. Male and female juveniles treated with 10 mg/kg of naltrexone SC for 9 days (days 21 to 29 of age) prior to and during behavioral testing (days 30 to 37) showed longer latencies to retrieve, group, and crouch over pups than did the vehicle-injected controls. These results suggest that opioids may have a stimulatory role in parental behavior during this prepubertal period.     

The verbal threat information pathway to fear in children: The longitudinal effects on fear cognitions and the immediate effects on avoidance behavior.

Verbal information has long been assumed to be an indirect pathway to fear. Children (aged 6-8 or 12-13 years) were exposed to threat, positive, or no information about 3 novel animals to see the long-term impact on their fear cognitions and the immediate impact on avoidance behavior. Their directly (self-report) and indirectly (implicit association task) measured attitudes toward the animals changed congruent with the information provided, and the changes persisted up to 6 months later. Verbal threat information also induced behavioral avoidance of the animal. Younger children formed stronger animal- threat and animal-safe associations because of threat and positive verbal information than older children, but there were negligible age effects on self-reported fear beliefs and avoidance behaviors. These results support theories of fear acquisition that suppose that verbal information affects components of the fear emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of conscientiousness and agreeableness on job performance.

The authors hypothesized that the relationship between conscientiousness and job performance would be stronger for persons high in agreeableness than for those low in agreeableness. Results of hierarchical moderated regression analyses for 7 independent samples of employees across diverse occupations provided support for the hypothesis in 5 of the samples. In samples supporting the hypothesis, among the highly conscientious workers, those low in agreeableness were found to receive lower ratings of job performance than workers high in agreeableness. One explanation for lack of an interaction between conscientiousness and agreeableness in the other 2 samples is that those jobs were not characterized by frequent, cooperative interactions with others. Overall, the results show that highly conscientious workers who lack interpersonal sensitivity may be ineffective, particularly in jobs requiring cooperative interchange with others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of positive affect and conscientiousness on strain.

The purpose of our study was to more fully investigate a combination of personal resources, namely positive affect (PA) and conscientiousness, on emotional exhaustion, depersonalization, and job tension. We examined a sample of nurses employed by a metropolitan hospital and found that the combination of high positive affect and high levels of conscientiousness was associated with lower levels of all strain variables. Our findings suggested that conscientiousness strengthened the negative relationship between PA and job strain. Our results were consistent with the view that some dispositions can act as resources protecting individuals from experienced stress. Implications of these results, strengths and limitations, and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of belongingness and charisma on helping and compliance.

This study tests the main and interactive effects of belongingness and perceived charismatic leadership on 2 forms of organizational citizenship behavior (helping and compliance). In line with expectations, a study of 115 manager-subordinate dyads demonstrates that employees show more helping (manager rated) when they have a stronger sense of belongingness at work and more helping as well as compliance when they perceive their leader to be more charismatic (subordinate rated). Belongingness partially mediates the relationship between charisma and helping. Also, as hypothesized, belongingness and charisma have interactive effects on employees' helping and compliance. The impact of perceived charisma on these behaviors is stronger for employees with a low sense of belongingness at work than for individuals with a higher sense of belongingness. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects of the naltrexone implant on rodent social interactions and cocaine-induced conditioned place preference

It is well known that excessive thyroid hormone in the body is associated with bone loss. However, the mechanism by which thyroid hormone affects bone turnover remains unclear. It has been shown that it stimulates osteoclastic bone resorption indirectly via unknown mediators secreted by osteoblasts. To determine if interleukin-6 (IL-6) or interleukin-11 (IL-11) could be the mediator(s) of thyroid hormone-induced bone loss, we studied the effects of 3,5,3'-tri-iodothyronine (T3) on basal and interleukin-1 (IL-1)-stimulated IL-6/IL-11 production in primary cultured human bone marrow stromal cells. T3 at 10(-12)-10(-8) M concentration significantly increased basal IL-6 production in a dose-dependent manner. It also had an additive effect on IL-1-stimulated IL-6 production, but failed to elicit a detectable effect on basal or IL-1-stimulated IL-11 production. Treatment with 17beta-estradiol (10(-8) M) did not affect the action of T3 on IL-6/IL-11 production. These results suggest that thyroid hormone may stimulate bone resorption by increasing basal and IL-1-induced IL-6 production from osteoblast-lineage cells, and these effects are independent of estrogen status.     

Selective effects of peripheral lipopolysaccharide administration on contextual and auditory-cue fear conditioning

The Drosophila embryonic mesoderm forms by invagination of the ventral-most blastoderm cells. Subsequent development of this germ layer involves the dorsolateral migration of the internalized cells and expansion by cell division, followed by the specification of particular cell fates through the coordinate actions of both intrinsic and extrinsic regulatory mechanisms. The latter include several intercellular signals that function across germ layers. These processes combine to generate a diversity of mesodermal sub-types, including the cardial and pericardial cells of the heart or dorsal vessel, a complete set of somatic muscle founders each with its unique identity, a population of cells that form the visceral musculature, and other cells that develop into hemocytes and the fat body. Here, we review recent evidence for the involvement of a fibroblast growth factor receptor (FGFR) encoded by the heartless (htl) gene in early directional migration of the Drosophila mesoderm. In addition, we provide new data that 1) demonstrate a second role for Htl in promoting the specification of the precursors to certain cardiac and somatic muscle cells in the Drosophila embryo, independent of its cell migration function, 2) suggest that Ras and at least one other signal transduction pathway act downstream of Htl, and 3) establish a functional relationship between the Ras pathway and Tinman (Tin), a homeodomain factor that is essential for specifying some of the same dorsal mesodermal cells that are dependent on Htl. Finally, parallels between requirements for FGFR signaling in Drosophila and vertebrate mesoderm development are considered.