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.     

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.     

College Men's Perceived Likelihood to Perpetrate Sexual Aggression

This study implemented a prospective design to explore the relationship between college men's perceived likelihood to perpetrate sexual aggression and their perpetration of sexual aggression over a three-month interim (N = 414). Compared to men's report of their likelihood to use physical force to obtain sex play or sexual intercourse, college men reported higher levels of perceived likelihood to use arguments or pressure to obtain sex play or sexual intercourse as well as drugs and alcohol to obtain sexual intercourse. Prospective analyses revealed that the majority of men who perpetrated sexual aggression over the follow-up period indicated that they were at some risk to do so at the pretest assessment. Implications for sexual assault prevention programming are discussed.     

The effect of video observation on warmth and competence ratings of individuals with a disability

ObjectivesThis study examined whether a video featuring an adult with a physical disability engaging in either sport, exercise, or an activity of daily living (ADL) can mitigate negative stereotypes of disability held by people without a disability.DesignThis study used a pre-post design, involving three participant groups.MethodsParticipants (n = 212) read a vignette describing an adult with a disability (target). Consistent with the stereotype content model, participants judged the target's warmth and competence. One week later, participants viewed a video of the target participating in sport, exercise, or an ADL and judged the target's warmth and competence.ResultsJudgements of competence but not warmth changed over time. The greatest increases occurred in the sport condition. At follow-up, the typical high warmth low competence stereotype of disability was reversed; the character was judged as being more competent than warm especially in the sport condition.ConclusionVideos of adults with a disability engaging in physical activity, particularly sport, have potential to mitigate negative stereotypes of disability.     

Active inference, sensory attenuation and illusions

Active inference provides a simple and neurobiologically plausible account of how action and perception are coupled in producing (Bayes) optimal behaviour. This can be seen most easily as minimising prediction error: we can either change our predictions to explain sensory input through perception. Alternatively, we can actively change sensory input to fulfil our predictions. In active inference, this action is mediated by classical reflex arcs that minimise proprioceptive prediction error created by descending proprioceptive predictions. However, this creates a conflict between action and perception; in that, self-generated movements require predictions to override the sensory evidence that one is not actually moving. However, ignoring sensory evidence means that externally generated sensations will not be perceived. Conversely, attending to (proprioceptive and somatosensory) sensations enables the detection of externally generated events but precludes generation of actions. This conflict can be resolved by attenuating the precision of sensory evidence during movement or, equivalently, attending away from the consequences of self-made acts. We propose that this Bayes optimal withdrawal of precise sensory evidence during movement is the cause of psychophysical sensory attenuation. Furthermore, it explains the force-matching illusion and reproduces empirical results almost exactly. Finally, if attenuation is removed, the force-matching illusion disappears and false (delusional) inferences about agency emerge. This is important, given the negative correlation between sensory attenuation and delusional beliefs in normal subjects—and the reduction in the magnitude of the illusion in schizophrenia. Active inference therefore links the neuromodulatory optimisation of precision to sensory attenuation and illusory phenomena during the attribution of agency in normal subjects. It also provides a functional account of deficits in syndromes characterised by false inference and impaired movement—like schizophrenia and Parkinsonism—syndromes that implicate abnormal modulatory neurotransmission.