Cognitive enhancement by drugs in health and disease

Attempts to improve cognitive function in patients with brain disorders have become the focus of intensive research efforts. A recent emerging trend is the use of so-called cognitive enhancers by healthy individuals. Here, we consider some of the effects - positive and negative - that current drugs have in neurological conditions and healthy people. We conclude that, to date, experimental and clinical studies have demonstrated relatively modest overall effects, most probably because of substantial variability in response both across and within individuals. We discuss biological factors that might account for such variability and highlight the need to improve testing methods and to extend our understanding of how drugs modulate specific cognitive processes at the systems or network level.     

The syntactic priming effect: Evoked response evidence for a prelexical locus

Twenty subjects made lexical decisions in a syntactic priming paradigm. Target stimuli (nouns, verbs, abiguous noun--verb words, and nonsense words) were immediately preceded on each trial by a function word syntactic prime, creating appropriate or inappropriate syntactic contexts for the real word targets. Evoked responses to the targets were recorded from left and right frontal, temporal, and temporoparietal sites. Principal components analysis revealed a component peaking at 140 msec which discriminated words in appropriate contexts from words in inappropriate contexts, independent of lexical syntactic class, with maximal discrimination at temporoparietal sites. Evidence for the identification of the syntactic class of target items was not observed in the evoked response until 80 msec after this syntactic priming effect occurred. These results suggest a prelexical locus for the syntactic priming effect. The implications of these results for current conceptions of the modularity of the mental lexicon are discussed.     

Evoked potential and visual half-field evidence for task-dependent cerebral asymmetries in congenitally deaf adults

Evoked potentials to laterally presented stimuli were collected from left and right tempero-parietal sites during performance of two visual half-field tasks, lexical decision, and line orientation discrimination. Reaction time and accuracy data were simultaneously collected. The behavioral data indicated the development of a right field advantage for the lexical decision task as a function of practice. A principal components analysis revealed three independent evoked potential components which displayed task-dependent hemispheric asymmetries. Multiple regression analyses revealed that visual half-field asymmetries in response accuracy were closely related to hemispheric asymmetries on several independent evoked response components. Subject's scores on independent tests of verbal reasoning and spatial relations were also found to be closely related to hemispheric asymmetry on several independent evoked response components. These data support a multidimensional concept of cerebral specialization. They also suggest that visual field asymmetries reflect the confluence of several underlying processes which have independent lateralization distributions across the population. In general, the results underscore the need for further research on the nature of the relationship between cerebral and perceptual asymmetries.     

Multiresolution Analysis of Event-Related Potentials by Wavelet Decomposition

Wavelet analysis is presented as a new tool for analyzing event-related potentials (ERPs). The wavelet transform expands ERPs into a time-scale representation, which allows the analyst to zoom in on the small scale, fine structure details of an ERP or zoom out to examine the large scale, global waveshape. The timescale representation is closely related to the more familiar time-frequency representation used in spectrograms of time-varying signals. However, time-scale representations have special properties that make them attractive for many ERP applications. In particular, time-scale representations permit theoretically unlimited time resolution for the detection of short-lived peaks and permit a flexible choice of wavelet basis functions for analyzing different types of ERPs. Generally, time-scale representations offer a formal basis for designing new, specialized filters for various ERP applications. Among recently explored applications of wavelet analysis to ERPs are (a) the precise identification of the time of occurrence of overlapping peaks in the auditory brainstem evoked response; (b) the extraction of single-trial ERPs from background EEG noise; (c) the decomposition of averaged ERP waveforms into orthogonal detail functions that isolate the waveforms experimental behavior in distinct, orthogonal frequency bands; and (d) the use of wavelet transform coefficients to concisely extract important information from ERPs that predicts human signal detection performance. In this tutorial we present an intuitive introduction to wavelets and the wavelet transform, concentrating on the multiresolution approach to wavelet analysis of ERP data. We then illustrate this approach with real data. Finally,we offer some speculations on future applications of wavelet analysis to ERP data.     

The Use of a Western Model across Cultures

A pilot project offering a Western-style anxiety-management group to Bangladeshi women in Tower Hamlets is described. The group approach provided an educational component, specific skills training and social support, all in Bangla (Bengali). Issues related to language, expectations, family involvement, therapists' self-disclosure and boundaries, and the choice of outcome measure, are fully described in a transcultural setting. Implications for practice are considered for the service providers, for Western counsellors and for the women themselves.     

Cortical locus of coherent motion deficits in deaf poor readers

Samar and Parasnis [Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. Brain and Cognition, 58, 300-311.] reported that correlated measures of coherent motion detection and perceptual speed predicted reading comprehension in deaf young adults. Because deficits in coherent motion detection have been associated with dyslexia in the hearing population, and because coherent motion detection is strongly dependent on extrastriate cortical area MT, these results are consistent with the claim that hidden dyslexia occurs within the deaf population and is associated with deficits in MT. However, coherent motion detection can also be influenced by subcortical deficits in both magnocellular and parvocellular pathways. To confirm the putative cortical locus of coherent motion perception deficits, we measured contrast thresholds for detecting the direction of movement of drifting sine wave gratings in the same participant group as [Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. Brain and Cognition, 58, 300-311.], under stimulus conditions that selectively biased for input from the subcortical magnocellular and parvocellular pathways, respectively. Contrast thresholds were not related to reading comprehension performance under either the magnocellular or parvocellular conditions. Furthermore, the previously reported correlations among reading comprehension, coherent motion thresholds, and perceptual speed remained significant even after contrast thresholds and non-verbal IQ were controlled in partial correlation analyses. In addition, coherent motion detection thresholds were found to correlate specifically with a reading-IQ discrepancy score, one commonly used indicator of dyslexia. These results provide direct psychophysical evidence that the previously reported deficit in coherent motion detection in deaf poor readers does not involve subcortical pathway deficits, but rather is associated with a cortical deficit likely involving area MT. They also strengthen the argument for the existence of hidden dyslexia in the deaf adult population.     

Perceptions of and Attitudes toward Plagiarism and Factors Contributing to Plagiarism: a Review of Studies

The abundance of information technology and electronic resources for academic materials has contributed to the attention given to research on plagiarism from various perspectives. Among the issues that have attracted researchers’ attention are perceptions of plagiarism and attitudes toward plagiarism. This article presents a critical review of studies that have been conducted to examine staff’s and students’ perceptions of and attitudes toward plagiarism. It also presents a review of studies that have focused on factors contributing to plagiarism. Our review of studies reveals that most of the studies on perceptions of plagiarism and attitudes toward plagiarism lack an in-depth analysis of the relationship between the perceptions of plagiarism and other contextual, sociocultural and institutional variables, or the relationship between attitudes toward plagiarism and students’ perceptions of various forms of plagiarism. Although our review shows that various factors can contribute to plagiarism, there is no taxonomy that can account for all these factors. Some suggestions for future research are provided in this review article.     

An exploratory assessment of cultural sensitivity in the practices of Lebanese researchers in the field of psychology: implications for national development efforts

The inclusion of the social and cultural characteristics of groups in the concept of national development highlights the contributions that culturally sensitive psychological research can make to development efforts. It also highlights the relevance of assessing and promoting such research, especially in majority world countries where development needs are pressing. In the current study, a content analysis was conducted to assess the degree to which Lebanese psychological researchers in post-civil war Lebanon have engaged in culturally sensitive research practices. The Cultural Sensitivity Measure for Published Research, which was inspired by Adair, Puhan, and Vohra's ( 1993 ) measure of indigenization, was applied to 54 peer-reviewed English- and French-language empirical studies conducted by Lebanese researchers on Lebanese samples within Lebanon. The results suggest that while cultural sensitivity levels were generally low, the sampled researchers engaged in more sensitive practices compared to researchers in the region. For example, they used qualitative methods more often, made more efforts to ensure the cultural compatibility of their methods, and engaged in more complex conceptualizations of culture and its relationship with psychological processes. Furthermore, certain practices, such as studying diverse groups or using findings to suggest real-life applications, were found to be predictive of higher general levels of cultural sensitivity in the sampled articles. These research practices could be fostered in institutional and intellectual contexts, and such initiatives would go a long way in supporting a locally appropriate research infrastructure that contributes to national development efforts.