Neurocognitive Effects of Methamphetamine: A Critical Review and Meta-analysis

This review provides a critical analysis of the central nervous system effects of acute and chronic methamphetamine (MA) use, which is linked to numerous adverse psychosocial, neuropsychiatric, and medical problems. A meta-analysis of the neuropsychological effects of MA abuse/dependence revealed broadly medium effect sizes, showing deficits in episodic memory, executive functions, information processing speed, motor skills, language, and visuoconstructional abilities. The neuropsychological deficits associated with MA abuse/dependence are interpreted with regard to their possible neural mechanisms, most notably MA-associated frontostriatal neurotoxicity. In addition, potential explanatory factors are considered, including demographics (e.g., gender), MA use characteristics (e.g., duration of abstinence), and the influence of common psychiatric (e.g., other substance-related disorders) and neuromedical (e.g., HIV infection) comorbidities. Finally, these findings are discussed with respect to their potential contribution to the clinical management of persons with MA abuse/dependence.     

Interval recording for duration events: a re‐evaluation

In two experiments, events that were recorded using continuous duration recording (CDR) were rescored using 10‐s partial interval (PIR), 10‐s momentary time sampling (MTS) and 20‐s MTS. Results of Experiment 1 showed that data paths generated by each interval method produced conclusions about functional control that were similar to those based on CDR when using reversal designs; however, for multielement designs, 10‐s PIR was prone to showing differentiation between data paths that was not evident with CDR. Results of Experiment 2 showed that both 10‐s and 20‐s MTS yielded data paths on behavior–behavior relations (e.g., covarying responses) that were consistent with CDR whereas 10‐s PIR produced some behavior–behavior patterns that were not. In both experiments, 10‐s MTS generated data paths that were nearly identical to the respective CDR data paths. The implications of these findings for researchers and clinicians are briefly discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Emergency Research without Consent under Polish Law

Although Directive 2001/20/EC of the European Parliament and of Council of 4 April 2001 on the approximation of the laws regulations and administrative provisions of the Member States relating to the implementation of good clinical practice in the conduct of clinical trials on medicinal products for human use does not contain an exception for emergency situations, and requires the informed consent of a legal representative in all cases where research is conducted on legally competent individuals who are unable to give informed consent, in Poland, emergency research can be conducted without consent. Polish regulations on emergency research can hardly be treated as a result of intentional legislative policy. Our provisions arise from multiple and sophisticated interpretations of different regulations that govern medical experiments on human subjects and clinical trials. These interpretations can be summarized as follows: (1) There are two categories of medical experiments: therapeutic and non-therapeutic experiments. Emergency research without consent may be conducted in the category of therapeutic experiment only (therapeutic experiment consists of the introduction by the physician of new or only partially proven diagnostic, therapeutic or preventive methods in order to achieve direct benefit to the health of the patients, and it can be carried out when hitherto applied methods were ineffective or their effectiveness was insufficient). (2). Emergency research may be conducted without consent if there is a situation of great urgency in which the research subject's life is in danger and there is no possibility of obtaining immediate consent from the research subject him or herself, or from his or her legal representative or guardianship court, and the research subject has not refused to give consent for the participation in an emergency therapeutic experiment. The legal representative or guardianship court shall be provided with all the relevant information concerning subject's participation in an experiment as soon as possible. All projects of emergency research with intent to be done without the research subject's consent must be approved by an independent bioethics committee. Because these five requirements seem to provide insufficient protection for a subject's autonomy and rights it is necessary to add to them two other conditions: (1) the emergency research could not be conducted using other research participants capable of giving informed consent; and (2) informed consent for continued participation in the emergency research shall be obtained from either the participant him or herself or the legally authorized representative as soon as possible (requirement of obtaining deferred consent). A consolidated single Act that will govern all aspects of medical experiments on human subjects, including emergency research, should be prepared and enacted as soon as possible.     

Primate errors in transitive ‘inference’: a two-tier learning model

Transitive performance (TP) is a learning-based behaviour exhibited by a wide range of species, where if a subject has been taught to prefer A when presented with the pair AB but to prefer B when presented with the pair BC, then the subject will also prefer A when presented with the novel pair AC. Most explanations of TP assume that subjects recognize and learn an underlying sequence from observing the training pairs. However, data from squirrel monkeys (Saimiri sciureus) and young children contradict this, showing that when three different items (a triad) are drawn from the sequence, subjects' performance degrades systematically (McGonigle and Chalmers, Nature 267:694-696, 1977; Chalmers and McGonigle, Journal of Experimental Child Psychology 37:355-377, 1984; Harris and McGonigle, The Quarterly Journal of Experimental Psychology 47B:319-348, 1994). We present here the two-tier model, the first learning model of TP which accounts for this systematic performance degradation. Our model assumes primate TP is based on a general-purpose task learning system rather than a special-purpose sequence-learning system. It supports the hypothesis of Heckers et al. (Hippocampus 14:153-162, 2004) that TP is an expression of two separate general learning elements: one for associating actions and contexts, another for prioritising associations when more than one context is present. The two-tier model also provides explanations for why phased training is important for helping subjects learn the initial training pairs and why some subjects fail to do so. It also supports the Harris and McGonigle (The Quarterly Journal of Experimental Psychology 47B:319-348, 1994) explanation of why, once the training pairs have been acquired, subjects perform transitive choice automatically on two-item diads, but not when exposed to triads from the same sequence.     

What is in a word? No versus Yes differentially engage the lateral orbitofrontal cortex

The words "No" and "Yes" are involved in conditioning to prohibit or encourage behavior, respectively. The authors, therefore, hypothesized that these words would be attributed to endogenous valence, activating neuronal circuits involved with valence and emotional control. Functional MRI (fMRI) at 4 Tesla was used to record regional brain activity while participants were exposed to emphatic vocalizations of the words. Results showed that No and Yes were associated with opposite brain-behavior responses; while No was negatively valenced, produced slower response times, and evoked a negative signal in the right lateral orbitofrontal cortex (OFC), Yes was positively valenced, produced faster response times, and evoked a positive signal in a contiguous region of the OFC. Attribution of negative valence to No and trait anger control were associated with increased responsivity of the OFC to No. Inasmuch as sensitivity to the prohibitive command No develops during childhood through interaction with primary caregivers as the first social objects, our findings may implicate the lateral OFC in the neurobiology of emotion regulation and subsequent social development.     

Inhibiting irrelevant information in adult children of people with alcoholism

Adult children of people with alcoholism (ACAs; n = 21) and adults with no family history of alcoholism (non-ACAs; n = 24) completed a task designed to test inhibitory ability using a reaction-time based negative priming task. Although participants in the ACA group responded more slowly overall, they did not differ on this task as compared with participants in the non-ACA group. This pattern of results suggests that inhibitory ability is preserved in ACAs, at least within the context of the current negative priming task. The authors discuss study limitations and inconsistencies in the ACA literature.     

When seeing what's wrong makes you right: The effect of erroneous examples on 3D diagram learning

Comprehending 3D diagrams is critical for success in scientific practice and research demonstrates that understanding of 3D geology diagrams can be improved by making predictive sketches. In mathematics, explaining erroneous examples can support learning. This study combined these approaches to better understand how to effectively support 3D geologic diagram understanding. Participants generated sketches, explained erroneous example sketches, or copied and explained correct sketches. It was hypothesized that generating sketches or explaining erroneous cases would improve understanding, but an open question was whether these conditions would differ from each other. Explaining erroneous examples and sketching improved understanding whereas explaining correct sketches did not. Further, explaining erroneous examples was a more efficient strategy than sketching. These results indicate that erroneous examples can be effective for supporting 3D diagram comprehension and may be a practical substitute for some traditional sketching activities in the context of real classrooms where class time is limited.     

IS SCIENCE PERSISTENCE A MATTER OF VALUES?

This study investigates the hypothesis that congruence in value perspectives distinguishes science-able students who persist in science from those who do not (nonpersisters). A science values measure was administered to 173 undergraduates with high levels of commitment and ability in the sciences. On each of six hypothetical dilemmas from everyday science, respondents rated the importance of three justice and three care considerations for self and for science, using a Likert-type 7-point scale. A significant three way interaction involving sex, persistence, and point of view (self/sience) emerged, with persisters generally demonstrating congruence between self and science on the value perspectives; female persisters, however, were more likely to combine justice and care perspectives than were males. Nonpersisters' self/science ratings of justice and care were sharply dissimilar, with females demonstrating the most incongruence. In all groups, justice was the prominent perspective attributed to science.