The constituent structure of autobiographical memory: autobiographical fluency in people with chronic epilepsy

A total of 59 people with chronic epilepsy recalled autobiographical episodes and personal facts (such as the names of friends or teachers) from various lifetime periods. Also tested was their verbal fluency and their fluency in generating items from semantic categories (animals, vegetables, US presidents, and British prime ministers). Results of a cluster analysis and a common factor analysis confirmed a dissociation between the retrieval of autobiographical information and that of nonpersonal semantic information. There was a similar dissociation between the recall of personal episodes and the recall of the personal information, but the corresponding factors were highly correlated with one another. Finally, verbal fluency performance was significantly correlated with the retrieval of personal information, personal episodes, and common objects, but not with that of public figures. The constituent structure of autobiographical fluency is extremely robust across different populations.     

Rapid modulation of distributed brain activity by Transcranial Magnetic Stimulation of human motor cortex

This paper reviews the effects of single and repetitive transcranial magnetic stimuli (rTMS) delivered to one cortical area and measured across distributed brain regions using electrophysiological measures (e.g. motor thresholds, motor evoked potentials, paired-pulse stimulation), functional neuroimaging (including EEG, PET and fMRI) and behavioural measures. Discussion is restricted to changes in excitability in the primary motor cortex and behaviour during motor tasks following transcranial magnetic stimulation delivered to primary motor and premotor areas. Trains of rTMS have lasting effects on the excitability of intrinsic and corticofugal neurones, altering the responsiveness of local and remote sites. These effects lead to distributed changes in synaptic activity at rest, and during a range of motor tasks. It is possible to impair or improve performance following rTMS, but for most simple motor tasks performance is unaltered. Changes in distributed activity observed with functional imaging during motor behaviour may represent compensatory activity, enabling maintenance of performance; stimulation of additional cortical areas appears to impair performance. A detailed understanding of the distributed changes in excitability following rTMS may facilitate future attempts to modulate motor behaviour in the healthy brain and for therapeutic purposes.     

A formal cognitive model of the go/no-go discrimination task: evaluation and implications

This article proposes and tests a formal cognitive model for the go/no-go discrimination task. In this task, the performer chooses whether to respond to stimuli and receives rewards for responding to certain stimuli and punishments for responding to others. Three cognitive models were evaluated on the basis of data from a longitudinal study involving 400 adolescents. The results show that a cue-dependent model presupposing that participants can differentiate between cues was the most accurate and parsimonious. This model has 3 parameters denoting the relative impact of rewards and punishments on evaluations, the rate that contingent payoffs are learned, and the consistency between learning and responding. Commission errors were associated with increased attention to rewards; omission errors were associated with increased attention to punishments. Both error types were associated with low choice consistency. The parameters were also shown to have external validity: Attention to rewards was associated with externalizing behavior problems on the Achenbach scale, and choice consistency was associated with low Welsh anxiety. The present model can thus potentially improve the sensitivity of the task to differences between clinical populations.     

The reliability and validity of the panic disorder self-report: a new diagnostic screening measure of panic disorder

This study examined the Panic Disorder Self-Report (PDSR), a new self-report diagnostic measure of panic disorder based on the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994). PDSR diagnoses were compared with structured interview diagnoses of individuals with generalized anxiety disorder, social phobia, and panic disorder and nonanxious controls. Receiver operating characteristic analyses revealed that the PDSR showed 100% specificity and 89% sensitivity. The PDSR also demonstrated retest reliability, convergent and discriminant validity, and kappa agreement of .93 with a structured interview. Finally, the PDSR demonstrated clinical validity. Students who were identified as having panic disorder using the PDSR did not have significantly different scores on the Panic Disorder Severity Scale--Self-Report form (P. R. Houck, D. A. Speigel, M. K. Shear, & P. Rucci, 2002) than a panic disordered community sample. However, both groups had significantly higher scores than students identified as not meeting criteria for panic disorder.     

Preferences for involvement in medical decision making: comparing British and German views

Despite beneficial outcomes of patients' involvement in medical decision processes, it has been claimed that patients are generally not interested in medical decision making (MDM). Whereas current research focuses on actual MDM, this research explored the impact of nationality and perceptual processes of MDM. Preferences for involvement in decision making were examined in a sample of 204 German and 143 British university students. Hierarchical multiple regressions were employed to explore the link between socio-demographic information, individuals' perceived relationship with their GP, Health Locus of Control - Powerful Others, perceptions regarding the frequency and sufficiency of information provision and involvement in MDM, and individuals' preferred level of involvement and information. A significant amount of the variance in individuals preferences for involvement could be explained (Adjusted R2 = .59, p < .001). Independent t-test analyses showed that British and German perceptions of care differed significantly on a variety of different measures. Separate analyses for the German and British group highlighted cross-national differences in care and preferences for involvement. The study suggests that preferences to become involved might depend more on perceptual processes than actual involvement in decision making, and that communication and national health policy could play an important role.     

Effects of category diversity on learning,memory, and generalization

In this study, we examined the effect of within-category diversity on people's ability to learn perceptual categories, their inclination to generalize categories to novel items, and their ability to distinguish new items from old. After learning to distinguish a control category from an experimental category that was either clustered or diverse, participants performed a test of category generalization or old-new recognition. Diversity made learning more difficult, increased generalization to novel items outside the range of training items, and made it difficult to distinguish such novel items from familiar ones. Regression analyses using the generalized context model suggested that the results could be explained in terms of similarities between old and new items combined with a rescaling of the similarity space that varied according to the diversity of the training items. Participants who learned the diverse category were less sensitive to psychological distance than were the participants who learned a more clustered category.     

Redintegration and lexicality effects in children: Do they depend upon the demands of the memory task?

The effect of long-term knowledge upon performance in short-term memory tasks was examined for children from 5 to 10 years of age. The emergence of a lexicality effect, in which familiar words were recalled more accurately than unfamiliar words, was found to depend upon the nature of the memory task. Lexicality effects were interpreted as reflecting the use of redintegration, or reconstruction processes, in short-term memory. Redintegration increased with age for tasks requiring spoken item recall and decreased with age when position information but not naming was required. In a second experiment, redintegration was found in a recognition task when some of the foils rhymed with the target. Older children were able to profit from a rhyming foil, whereas younger children were confused by it, suggesting that the older children make use of sublexical phonological information in reconstructing the target. It was proposed that redintegrative processes in their mature form support the reconstruction of detailed phonological knowledge of words.     

Similarity as transformation

We propose that similarity is determined by the transformation distance between representations: entities which are perceived to be similar have representations which are readily transformed into one another, whereas transforming between dissimilar entities requires many transformations. We present three experiments that indicate that similarity is strongly influenced by transformation distance. These data present a challenge for featural or spatial accounts of similarity. Finally, we introduce a family of transformation-based accounts of similarity, called 'Representational Distortion', as a specific example of a transformational approach to similarity.