Experimental challenges to theories of classical conditioning: application of an attentional model of storage and retrieval

Several studies have recently challenged the accuracy of traditional models of classical conditioning that account for some experimental data in terms of a storage deficit. Among other results, it has been reported that extinction of the blocking or overshadowing stimulus results in the recovery of the response to the blocked or overshadowed stimulus, backward blocking shows spontaneous recovery, extinction of the training context results in the recovery from latent inhibition, interposing a delay between conditioning and testing in latent inhibition increases latent inhibition, and latent inhibition antagonizes overshadowing. An existing neural network model of classical conditioning (N. A. Schmajuk, Y. Lam, & J. A. Gray, 1996), which includes an attentional mechanism controlling both storage and retrieval of associations, is able to quantitatively describe these results.     

Associative activation of stimulus representations restores lost salience: implications for perceptual learning

In 3 experiments, rats received preexposure to presentations of a compound flavor BX. The effective salience of B was then tested by assessing its ability to interfere with the aversion controlled by another flavor or the tendency to drink a saline solution after the induction of a salt need. It was found that the effective salience of B was maintained when during preexposure, presentations of BX alternated with presentations of X alone. This was true both when BX was presented as a simultaneous compound (Experiment 1) and as a serial compound (X-->B; Experiments 2 and 3); salience was not maintained when the serial compound took the form B-->X (Experiments 2 and 3a). It was argued that the salience of B declines during preexposure but is restored when presentations of X are able to activate the representation of B by way of the associative X-B link.     

Vocational choice and career planning. Spanish adaptation of Holland's Self-Directed Search (SDS-R)

The Self-Directed Search is a career-planning guide that works similarly to a vocational and professional interests inventory. A preliminary study allows detection of 68 ítems that need to be rectified, since they do not meet psychometric and semantic criteria. The current study demonstrates reliability and validity of the new adaptation. It is applied to a sample of 1460 subjects from different educational levels. As for reliability, the discrimination index of the items and internal consistency of the scales have improved. Additionally, procedures performed to verify validity (content, construct and concurrent) demonstrate that the instrument has acceptable validity. On balance, we can conclude that the instrument has sufficient scientific and technical credibility for application to the Spanish population.     

Anxiolytic-like activity of SB-205384 in the elevated plus-maze test in mice

Recent studies point to a major role for alpha2-containing GABA-A receptors in modulating anxiety. However, the possible implication of GABA-A receptors containing the alpha3 subunit on anxiety is less known. The aim of this study was to examine the effects of SB-205384 (0.5-4 mg/kg, i.p.), an alpha3 subunit positive modulator of GABA-A receptor, on anxiety tested in the elevated plus-maze in male mice, using classical and ethological parameters. Mice treated with SB-205384 showed an increase in the frequency of entries and the time spent in open arms, as well as a reduction in the time spent in closed arms, as compared with the control group. A notable increase of "head-dipping" unprotected and a reduction of "stretched-attend posture" protected was also evident. These findings indicate that SB-205384 exhibits an anxiolytic-like profile in the elevated plus-maze test, suggesting that GABA-A receptors which contain the alpha3 subunit might be involved in regulation of anxiety.     

Selective attention affects implicit and explicit memory for familiar pictures at different delay conditions

Three experiments investigated the effects of two variables -selective attention during encoding and delay between study and test- on implicit (picture fragment completion and object naming) and explicit (free recall and recognition) memory tests. Experiments 1 and 2 consistently indicated that (a) at all delays (immediate to 1 month), picture-fragment identification threshold was lower for the attended than the unattended pictures; (b) the attended pictures were recalled and recognized better than the unattended; and (c) attention and delay interacted in both memory tests. For implicit memory, performance decreased as delay increased for both attended and unattended pictures, but priming was more pronounced and lasted longer for the attended pictures; it was still present after a 1-month delay. For explicit memory, performance decreased as delay increased for attended pictures, but for unattended pictures performance was consistent throughout delay. By using a perceptual object naming task, Experiment 3 showed reliable implicit and explicit memory for attended but not for unattended pictures. This study indicates that picture repetition priming requires attention at the time of study and that neither delay nor attention dissociate performance in explicit and implicit memory tests; both types of memory require attention, but explicit memory does so to a larger degree.     

Relation availability was not confounded with familiarity or plausibility in Gagné and Shoben (1997): Comment on Wisniewski and Murphy (2005)

C. L. Gagné and E. Shoben (1997) proposed that the conceptual system contains information about how concepts are used to modify other concepts and that this relational information influences the ease with which concepts combine. Recently, E. J. Wisniewski and G. L. Murphy suggested that C. L. Gagné and E. Shoben's measure of relation availability was confounded with familiarity and plausibility and that the participants could simply retrieve the stored meanings of the phrases because the phrases were not novel. In this article, the authors demonstrate that E. J. Wisniewski and G. L. Murphy's plausibility and familiarity judgments are dependent variables that (a) are themselves responsive to changes in relation availability, (b) modifier relation availability predicts response time even when the influence of phrase familiarity and plausibility is controlled, and (c) the materials consisted of mainly novel phrases.     

Generalization of tacting actions in children with autism

This intervention compared the effects of two procedures on the generalization of a tacting repertoire (labeling) in 6 children with autism spectrum disorder. In one procedure the verbal antecedent stimulus “What is she doing?” appeared together with a person performing an action; in the other procedure, the antecedent stimulus was just the presence of the action. In initial tests, children emitted tacts only when the action was presented with the verbal antecedent. Thereafter, they learned to tact an action without the verbal antecedent and received tests to evaluate generalization to another action. Results indicated that in order to obtain generalization of tacting actions, it was necessary to learn to tact other actions without the verbal antecedent as well as learning to tact the action with the verbal antecedent. These findings have relevance for generalization of tacting actions from control by verbal antecedents to natural conditions and the production of spontaneous language.     

Work-related stress and well-being: the roles of direct action coping and palliative coping

The purpose of the present study is to analyze the roles of direct action coping and palliative coping in the relationship between work stressors and psychological well-being, as well as their possible interactions, in a sample of 464 bank employees. Hierarchical regression analyses showed main effects of direct action coping on well-being. Palliative coping predicts higher levels of psychological distress. Contrary to what was expected, the interactions between work stressors and direct action coping were not significant. Palliative coping interacted with work stressors when predicting psychosomatic complaints. The interaction between the two types of coping was significant on psychosomatic complaints and psychological distress, but not on job satisfaction. The paper discusses theoretical and practical implications of these results, in order to design intervention strategies to prevent and manage job stress.     

Neuroprotection and stroke rehabilitation: modulation and enhancement of recovery

Recent advances in research are modifying our view of recovery after nervous system damage. New findings are changing previously held concepts and providing promising avenues for treatment of patients after stroke. This review discusses mechanisms of neuronal injury after brain ischemia and the attempts to study neuroprotection options based on such mechanisms. It also considers measures available at present to improve outcome after stroke and presents new areas of research, particularly stimulation techniques, neurogenesis and trophic factors to enhance recovery. In order to improve outcomes, medications that may be detrimental to recovery should be avoided, while symptomatic therapy of problems such as depression, pain syndromes and spasticity may contribute to better results. Continued surveillance and early treatment of complications associated with acute stroke, along with supportive care remain the mainstay of treatment for stroke patients in the recovery phase. Present research on limiting brain damage and improving recovery and plasticity enhance the prospects for better clinical treatments to improve recovery after stroke.