Endogenous opioids, blood pressure, and diffuse noxious inhibitory controls: a preliminary study

A 2003 study suggested that there are age differences in diffuse noxious inhibitory controls (DNIC), a form of endogenous pain inhibition. The present report describes a followup study employing a pharmacological blockade of endogenous opioids, i.e., using naloxone, in a small subset (n=6) of healthy young volunteers to characterize the opioid-dependence of DNIC, as well as DNIC's association with cardiovascular reactivity. Findings suggested that, while opioid blockade enhanced cardiovascular reactivity to cold pain, DNIC was not affected by administering naloxone. Interestingly, greater cardiovascular responses to noxious cold were associated with enhanced DNIC in this small sample. This relationship, which did not appear opioid-dependent, supports previous models integrating cardiovascular activity with the functioning of pain-modulatory systems.     

The Development of Aggression in 18 to 48 Month Old Children of Alcoholic Parents

This study examined the development of aggressive and oppositional behavior among alcoholic and nonalcoholic families using latent growth modeling. The sample consisted of 226 families assessed at 18, 24, 36, and 48 months of child age. Results indicated that children in families with nonalcoholic parents had the lowest levels of aggressive behavior at all time points compared to children with one or more alcoholic parents. Children in families with two alcoholic parents did not exhibit normative decreases in aggressive behavior from 3 to 4 years of age compared to nonalcoholic families. However, this association was no longer significant once a cumulative family risk score was added to the model. Children in families with high cumulative risk scores, reflective of high parental depression, antisocial behavior, negative affect during play, difficult child temperament, marital conflict, fathers’ education, and hours spent in child care, had higher levels of aggression at 18 months than children in low risk families. These associations were moderated by child gender. Boys had higher levels of aggressive behavior at all ages than girls, regardless of group status. Cumulative risk was predictive of higher levels of initial aggressive behavior in both girls and boys. However, boys with two alcoholic parents had significantly less of a decline in aggression from 36 to 48 months compared to boys in the nonalcoholic group.     

Translating multiple assessment techniques into an intervention selection model for classrooms

Translating current research to school-based clinical practice highlights issues not often encountered in laboratory settings. With the assistance of a consultant, teachers conducted functional analyses, brief multielement treatment comparisons, and controlled treatment evaluations under naturalistic conditions in the classroom. Teachers also provided input on treatment selection. Treatment integrity data collected throughout the study suggested that teachers implemented analyses and treatments with high integrity. The functional analysis outcomes combined with effectiveness and acceptability data led to the selection of interventions that reduced problem behavior in the classrooms for each of 3 children.     

Inhibition of endogenous carbon monoxide production induces transient retention losses in the day-old chick when trained using a single trial passive avoidance learning task

Carbon monoxide (CO) is most often thought of as an exogenous toxin rather than as a possible endogenous nootrope. However, a limited number of studies have suggested that CO is necessary in memory processing for at least some tasks. While nitric oxide (NO) and CO are known activators of guanylyl cyclase (GC), only the effect of NO on GC has been extensively investigated as a mechanism underlying memory processing. The aim of the present study was to determine if inhibition of CO production would have an effect on memory processing. Using chicks trained on a single trial passive avoidance task, inhibition of CO production using zinc (II) deuteroporphyrin IX 2,4-bis ethylene glycol (ZnBG; 5 microM) resulted in two transient retention losses occurring at around 40 and 130 min post-training. The timing of these transient retention losses was similar to those observed following inhibition of GC, using the same species and task in a previous study. This supports the notion that CO is necessary in memory processing for this task and may act through a GC-dependent mechanism. As ZnBG also directly inhibits GC or nitric oxide synthase (NOS) at high concentrations, a second experiment was carried-out to confirm the specificity of ZnBG for heme oxygenase (HO) at the concentration used. The action of ZnBG was challenged with the HO agonist hemin (100 microM) and the transient deficits were abolished. This confirmed that the action of ZnBG on memory was through a CO-related mechanism rather than directly on GC or NOS. In this way the specificity of ZnBG (5 microM) for HO could be confirmed. The results support a role for endogenous CO in memory processing, possibly through activation of GC. In addition, the transient retention losses observed following administration of ZnBG suggest that CO may be necessary for memory retrieval and not formation as previously thought.     

Implications of the Cattell-Horn-Carroll theory on ethnic differences in IQ

The Cattell-Horn-Carroll theory of intelligence and the Spearman-Jensen hypothesis were applied to help interpret mean IQ differences among ethnic groups. The Cattell-Horn-Carroll theory classifies cognitive abilities on three strata, which differ by magnitude of generality including specific, broad, and general abilities. The Spearman-Jensen hypothesis advances the belief that mean IQ differences between African Americans and Euro-Americans occur as a function of the test's g loadings. Although IQ differences between African Americans and Euro-Americans occur, the differences should be larger on tests with higher g loadings and smaller on tests with lower g loadings. The analysis described in this paper may serve as the catalyst to encourage all intelligence test publishers to supply test users with data regarding mean IQ differences among various ethnic groups.     

Inhibition of monoADP-ribosylation prevents long-term memory consolidation of a single-trial passive avoidance task in the day-old chick

The cytosolic posttranslational protein-modifying mechanism of monoADP-ribosylation has been implicated in long-term potentiation, a synaptic model of memory formation. The current study investigated the effect of inhibiting mono(ADP-ribosyl) transferase on memory for the passive avoidance task in day-old chicks (white Leghorn-black Australorp). Various doses of novobiocin or menadione sodium bisulfite were administered intracranially at different times before or after training. Control chicks were administered saline at matched times. Novobiocin (650 microM) or menadione sodium bisulfite (250 microM) administered between 5.0 min pretraining and 2.5 min posttraining was found to cause a persistent loss of retention from 120 min posttraining. These data provide the first demonstration that monoADP-ribosylation is required for the maintenance of long-term memory. Furthermore, the temporal characteristics of the memory loss caused by monoADP-ribosylation inhibition appears to exclude this mechanism as a downstream effect of the well-established nitric oxide activity previously shown to occur within 40 min of passive avoidance training.     

Effects of Causal Structure on Decisions About Where to Intervene on Causal Systems

We investigated how people design interventions to affect the outcomes of causal systems. We propose that the abstract structural properties of a causal system, in addition to people's content and mechanism knowledge, influence decisions about how to intervene. In Experiment 1, participants preferred to intervene at specific locations (immediate causes, root causes) in a causal chain regardless of which content variables occupied those positions. In Experiment 2, participants were more likely to intervene on root causes versus immediate causes when they were presented with a long‐term goal versus a short‐term goal. These results show that the structural properties of a causal system can guide the design of interventions.