d-Serine facilitates the effects of extinction to reduce cocaine-primed reinstatement of drug-seeking behavior

Male Sprague Dawley rats were allowed to self-administer cocaine (0.5 mg/kg) during 90 min sessions for a period of 15 days. On day 16, rats were either held abstinent in their home cage environment or experienced an extinction session in which the active lever had no programmed consequences. Facilitating N-methyl-d-aspartate (NMDA) receptor activity with the coagonist d-serine (100 mg/kg i.p.) before or following the extinction session significantly reduced the subsequent cocaine-primed reinstatement of drug-seeking behavior tested on day 17. d-Serine significantly reduced drug-primed reinstatement only when combined with extinction, and its effectiveness when administered following the training session suggested that an enhancement of consolidation of extinction learning had occurred. In contrast, d-serine treatment did not reduce sucrose-primed reinstatement, indicating that the beneficial effects of this adjunct pharmacotherapy with extinction training were specific to an addictive substance (cocaine) and did not generalize to a natural reward (sucrose).     

The effect of varying the number of response alternatives in rating scales: Experimental evidence from intra-individual effects

Despite a hundred years of questionnaire testing, no consensus has been reached on the optimal number of response alternatives in rating scales. Differences in prior research may have been due to the use of various psychometric models (classical test theory, item factor analysis, and item response theory) and different performance criteria (reliability, convergent/discriminant validity, and internal structure of the questionnaire). Furthermore, previous empirical studies on this issue have tackled the experimental design from a between-subjects perspective, thus ignoring intra-individual effects. In contrast with this approach, we propose a within-subjects experimental design and a comprehensive statistical methodology using structural equation models for studying all of these aspects simultaneously, therefore increasing statistical power. To illustrate the method, two personality questionnaires were examined using a repeated measures design. Results indicated that as the number of response alternatives increased, (1) internal consistency increased, (2) there was no effect on convergent validity, and (3) goodness of fit worsened. Finally, the article assesses the practical consequences of this research for the design of future personality questionnaires.     

Personality and the coherence of psychotherapy narratives

The stories people construct about themselves and their social worlds are key aspects of their identities [Bruner, J. S. (1990). Acts of meaning. Cambridge, MA: Harvard University Press; McAdams, D. P. (2001). The psychology of life stories. Review of General Psychology, 5, 100–122]. Whereas certain expected life experiences (e.g., leaving home, getting a job) may be relatively easy to narrate, more unexpected and difficult events, such as undergoing psychotherapy, may pose a challenge to successful narration. Yet it is especially important to successfully narrate one’s experience in psychotherapy in order to maintain the gains from treatment [Frank, J. D. (1961). Persuasion and healing: A comprehensive study of psychotherapy. Baltimore, MD: Johns Hopkins University Press; Spence, D. P. (1982). Narrative truth and historical truth: Meaning and interpretation in psychoanalysis. New York: W.W. Norton]. The present study collected psychotherapy narratives from 76 adult former clients and coded them for the fundamental story criterion of coherence [Baerger, D. R., & McAdams, D. P. (1999). Life story coherence and its relation to psychological well-being. Narrative Inquiry, 9, 69–96]. Former clients that were high in trait Openness to experience and those at higher stages of ego development told more coherent stories about therapy. The relationship between ego development and narrative coherence remained significant even when controlling for Openness. The findings suggest that high ego development may provide narrators with the kind of sophisticated frameworks for meaning-making that are especially well-suited for the important task of making good sense of psychotherapy.     

The morphosyntactic decomposition and semantic composition of German compound words investigated by ERPs

In two experiments, we investigated the morphosyntactic decomposition and semantic composition of acoustically presented German compound words. A left-anterior negativity (LAN) was found in the ERP for gender incongruent, initial compound constituents although these constituents are syntactically irrelevant in German. This LAN provides online evidence for morphosyntactic decomposition. Experiment 1 showed also preliminary evidence for semantic composition, which was further investigated in Experiment 2 by comparing semantically transparent and opaque compounds. Transparent compounds elicited an increased negativity with a centroparietal maximum that occurred during the presentation of the head constituent. This negativity is suggested to reflect the semantic integration of compound constituents that is necessary after the constituents have been accessed separately.     

A new method of monitoring motor activity in baboons

Movement activity of a normal baboon and of a baboon with induced Parkinsonism by unilateral administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was recorded by the Walter Reed Activity Monitor (or actigraph). Mean activity in the lesioned baboon was 41% less than that of the nonlesioned baboon measured over a 14-day period. In addition, the daily maximum activity value was significantly less in the MPTP-treated baboon. Moreover, resting and sleeping periods were 30% greater in the lesioned animal. The akinesia and resting and sleeping periods were displayed by the lesioned baboon throughout the day, whereas the control baboon showed them only at night. The data representing summarized movement activity are in accordance with observations of bradykinesia, hypokinesia, and akinesia of the MPTP-treated baboon. The actigraph was well tolerated by the animal because its small size and weight made it largely unobtrusive. We suggest that the actigraph is an appropriate device for measuring motor activity in nonhuman primates.     

Comparison of lingual vibrotactile suprathreshold numerical responses in men and women: effects of threshold shift during magnitude-estimation scaling

The purpose of this study was to investigate differences in tactile sensory system function between men and women. This task was accomplished by studying the effects of possible tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. 12 men (M age = 19.7 yr.) and 12 women (M age = 19.3 yr.) participated. Analysis suggested that men and women have tactile sensory systems that operate similarly at both threshold and suprathreshold levels of stimulation. Men and women do, however, choose to use consistently different numerical responses to suprathreshold stimuli, suggesting that environmental and/or cultural-educational influences may be involved in numerical decision-making aspects of the scaling process.