Naloxone administration impairs autoshaped learning

Effects of naloxone on acquisition of autoshaped behavior were investigated. Rats deprived to 85% of free-feeding weights were trained to touch a retractable lever; delivery of a food pellet occurred on every trial following lever retraction. The lever was retracted immediately if a touch occurred within 15 s, or automatically after 15 s. Analyses were conducted on number and latencies of touches of the extended lever, nose-pokes (touches) directed at the retracted lever during intertrial intervals (a measure less constrained by ceiling effects than extended lever touches), and unconditioned exploratory rearing activity, measured as touches of a metal strip mounted above the grid floor of the apparatus. In an initial experiment, male Sprague-Dawley rats were given saline or naloxone (2.0 mg/kg, ip) 5 min before a training session of 12 trials. Two days later they were tested, in the absence of drug, in a session of 36 (three blocks of 12) trials. Naloxone depressed training levels of lever responding, in addition to slowing acquisition rate. No effect of naloxone was observed on rearing activity. Previous work showed that injection of saline 5 min before behavioral testing increases the rate of autoshaping compared to injections 30 min before (Messing & Sparber, 1984). Thus, effects of naloxone on acquisition of lever-directed behaviors may have been confounded by behavioral depressant effects and/or by an injection effect such a short time before testing. In a second experiment naloxone (0.5 or 2.0 mg/kg) was injected after five of seven training sessions (12 trials each) to male and female rats. A 6-s delay of reinforcement was inserted between lever retraction and food delivery, slowing acquisition rates and providing the opportunity to test the effects of naloxone throughout a multiple-session task. The low dose retarded acquisition of extended lever touching in both sexes; both doses retarded acquisition of interim lever touching in males. Thus, in some circumstances, post-training naloxone administration may impair learning. The results support the notion that low doses of naloxone may have agonist activity.     

Testing Posttraumatic Stress as a Mediator of Childhood Trauma and Adult Intimate Partner Violence Victimization

This study examined whether potential posttraumatic stress disorder (PTSD) mediated the relationships between different forms of childhood trauma (sexual abuse, physical abuse, violence between caregivers) and intimate partner violence (IPV) victimization (psychological, physical, sexual). Participants were 1,150 female nurses and nursing personnel. Path analytic findings revealed potential PTSD partially mediated the relationships between childhood sexual abuse and psychological IPV and childhood sexual abuse and sexual IPV. Potential PTSD did not mediate the relationship between other types of childhood trauma and IPV. This study adds to the literature indicating PTSD as a risk factor for revictimization in the form of adult IPV among women. Screening for and treatment of PTSD among female child sexual abuse survivors could prevent future IPV victimization.     

Prevalence and correlates of suicidal behavior among adult female victims of intimate partner violence

The prevalence and correlates of suicidal threats and attempts among 662 racially and ethnically diverse adult female victims of intimate partner violence (IPV) were studied. One in five women had threatened or attempted suicide during her lifetime. They observed that multiple logistic regression results indicated that women at greater risk of severe or potentially lethal assaults as measured by the Danger Assessment and those who reported having a chronic or disabling illness were more likely to have threatened or attempted suicide. A linear association was found between age and suicide threats/attempts, with younger women having increased odds. Finally, African American IPV victims were less likely to have threatened or attempted suicide as compared to Latina victims. Study implications are discussed.     

Mediation: An Intervention Strategy for Counselors

Conflict resolution is a rapidly expanding field, one in which counselors need to be more knowledgeable. An overview of conflict resolution and mediation concepts is presented with a comparison to therapeutic counseling interventions. Applications are provided for various areas such as family mediation, community disputes, and mediation in public education. Implications for counseling and the role of the counselor are discussed.     

Summation of pain produced in different anatomical regions*

Unescapable shock was administered to rats in a spatial preference task through pairs of electrodes implanted subcutaneously near the neck and tail. The animals were permitted to choose between shock through both pairs of electrodes or through one pair by crossing from one side of a cage to the other. Rats preferred shock in two locations to an equal amount in one location. The results indicate that summation of pain is greater when stimuli are added in the same rather than in different places.     

Likelihood ratio, optimal decision rules, and correct response probabilities in a signal detection theoretic, equal-variance Gaussian model of the observer in the 4IAX paradigm

This article provides a synthetic account of the likelihood ratio, optimal decision rules, and correct response probabilities in a signal detection theoretic model of the observer in the dual-pair comparison, or four-interval AX (4IAX), paradigm. The model assumes a static sampling process, resulting in four, equal-variance normally distributed (i.e., Gaussian) observations on each trial First, a likelihood ratio equation allowing for an arbitrary degree of correlation between observations is provided. Specific solutions for the cases of independent and highly correlated observations are then derived. It is shown that these solutions, and the associated decision rules, correspond to those provided independently in earlier publications. A modified 4IAX paradigm involving, as a standard, an additional stimulus (C) located medially between the A and the B stimuli is also considered. It is shown that the optimal (static, equal-variance, Gaussian) decision model for this paradigm is unaffected by correlation between observations and is equivalent to the standard 4IAX with highly correlated observations. Finally, we consider how, under the considered (static, equal-variance, Gaussian) model, the proportion of correct responses in the different versions of the 4IAX paradigm is related to d', and a solution for the case of independent observations is provided.     

Acquired Capability for Suicide,Pain Tolerance,and Fearlessness of Pain—Validation of the Pain Tolerance Scale of the German Capability for Suicide Questionnaire

The interpersonal theory of suicide (Joiner, 2005) postulates that for a serious suicide attempt, one has to possess the acquired capability to commit suicide. Acquired capability includes higher pain tolerance, which is further assumed to comprise both an elevated physical pain tolerance and fearlessness of pain. Recently, the German Capability for Suicide Questionnaire (GCSQ) was validated. The aim of this study is further validation of the GCSQ's Pain Tolerance scale by investigating the scale's association with objective pain tolerance and fearlessness of pain in two undergraduate samples (N = 81; N = 76). Both associations were found indicating a strong criterion validity of the Pain Tolerance scale.