Health-related quality of life in Parkinson's disease after pallidotomy and deep brain stimulation

This study explored the multidimensional outcome of three neurosurgical interventions for Parkinson's disease (PD): pallidotomy (N = 23), pallidal deep brain stimulation (DBS) (N = 9), and thalamic DBS (N = 7). All patients completed the Sickness Impact Profile (SIP) and the Beck Depression Inventory. Pallidotomy patients also completed the Profile of Mood States, the Beck Anxiety Inventory, and a disease-specific quality of life (QOL) measure, the Parkinson's Disease Questionnaire (PDQ-39). Three months after surgery, all neurosurgical groups showed significant improvements in mood and function, including physical, psychosocial, and overall functioning. Pallidal DBS and pallidotomy patients who completed additional QOL measures reported decreased anxiety and tension, increased vigor, improved mobility and ability to perform activities of daily living, and decreased perceived stigma. Psychosocial dysfunction scores from the SIP were related to depressed mood both at baseline (r = .42) and at followup (r = .45), but the physical dysfunction subscale was not related to mood at either time point, suggesting that disruption of social relationships due to PD may have more impact on affective distress than physical symptoms alone. Results suggest that neurosurgical interventions for PD improve disabling PD motor symptoms and also improve several domains of quality of life.     

Assessing the empirical validity of the "take-the-best" heuristic as a model of human probabilistic inference

The boundedly rational 'Take-The-Best" heuristic (TTB) was proposed by G. Gigerenzer, U. Hoffrage, and H. Kleinb?lting (1991) as a model of fast and frugal probabilistic inferences. Although the simple lexicographic rule proved to be successful in computer simulations, direct empirical demonstrations of its adequacy as a psychological model are lacking because of several methodical problems. In 4 experiments with a total of 210 participants, this question was addressed. Whereas Experiment 1 showed that TTB is not valid as a universal hypothesis about probabilistic inferences, up to 28% of participants in Experiment 2 and 53% of participants in Experiment 3 were classified as TTB users. Experiment 4 revealed that investment costs for information seem to be a relevant factor leading participants to switch to a noncompensatory TTB strategy. The observed individual differences in strategy use imply the recommendation of an idiographic approach to decision-making research.     

Pharmacotherapy of paraphilias in the next millennium

Paraphilias are psychiatric disorders of abnormal sexual behavior whose prevalence has markedly increased during the last decade. Treatment modalities currently used fall into three categories: surgical castration, psychotherapy, and pharmacotherapy. The pharmacological interventions consist of antiandrogens that either completely reduce testosterone secretion and/or antagonize the action of testosterone at the level of the receptor, and psychotropic drugs, namely antidepressants. Cyproterone and medroxyprogesterone acetates are the two antiandrogens more commonly used. They are only effective in relatively high doses, but have a substantial number of severe side effects which has considerably limited their use. Psychotropic drugs may be effective solely in men with a definite obsessive-compulsive disorder component. Because of the erratic results and lack of permanent eradication of the paraphilic manifestations their use in paraphilias is highly controversial. Long-acting gonadotropin-releasing hormone (GnRH) agonist analogues are the most potent antiandrogens, and selectively abolish testosterone secretion in a totally reversible fashion. They are administered parenterally once every 1 to 3 months, and have the fewest side effects. Long-acting GnRH analogues, together with psychotherapy, are highly effective in controlling selected paraphilias (pedophilia, exhibitionism, and voyeurism), and are the most promising mode of therapy in the next millennium. There is an urgent need for good methodological research; carefully designed double-blind controlled studies with a large number of subjects in order to validate or not the use of the various pharmacotherapies.     

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.     

The processing of free and bound gender-marked morphemes in speech production: evidence from Dutch

In many languages, the production of noun phrases requires the selection of gender-marked elements like determiners or inflectional suffixes. There is a recent debate as to whether the selection of freestanding gender-marked elements, such as determiners, follows the same processing mechanisms as the selection of bound gender-marked morphemes, such as adjective suffixes. Most of the evidence on which this debate is based relates to the gender-congruency effect in picture-word interference experiments. In the present article, the authors address this issue with a pure picture-naming task, extending previous work in German (H. Schriefers, J. D. Jescheniak, & A. Hantsch, 2005). The results of the present study on noun phrase production in Dutch show that both types of gender-marked morphemes are selected via the same basic processing mechanisms.     

The Isolation, Primacy, and Recency Effects Predicted by an Adaptive LTD/LTP Threshold in Postsynaptic Cells

An item that stands out (is isolated) from its context is better remembered than an item consistent with the context. This isolation effect cannot be accounted for by increased attention, because it occurs when the isolated item is presented as the first item, or by impoverished memory of nonisolated items, because the isolated item is better remembered than a control list consisting of equally different items. The isolation effect is seldom experimentally or theoretically related to the primacy or the recency effects—that is, the improved performance on the first few and last items, respectively, on the serial position curve. The primacy effect cannot easily be accounted for by rehearsal in short-term memory because it occurs when rehearsal is eliminated. This article suggests that the primacy, the recency, and the isolation effects can be accounted for by experience-dependent synaptic plasticity in neural cells. Neurological empirical data suggest that the threshold that determines whether cells will show long-term potentiation (LTP) or long-term depression (LTD) varies as a function of recent postsynaptic activity and that synaptic plasticity is bounded. By implementing an adaptive LTP-LTD threshold in an artificial neural network, the various aspects of the isolation, the primacy, and the recency effects are accounted for, whereas none of these phenomena are accounted for if the threshold is constant. This theory suggests a possible link between the cognitive and the neurological levels.     

What people believe about memory

Two representative samples of adult Norwegians (n=2000) were asked a set of general and specific questions regarding their beliefs and opinions about human memory. The results indicate that on many questions, such as time of the earliest memories, inhibiting effects of collaboration, and memory for dramatic versus ordinary events, the views of the general public concurred with current research findings, and people in general had realistic views about their own memory performance. On other questions, such as the reliability of olfactory as compared with visual and auditory memory, the memory of small children in comparison with that of adults, the likelihood of repression of adult traumatic memories, and on more general questions such as the possibility of training memory and the capacity limitations of long-term memory, a large proportion of the participants expressed views that are less supported by scientific evidence. Implications of these findings are briefly discussed.     

Different parameters support generalization and discrimination learning in Drosophila at the flight simulator

We have used a genetically tractable model system, the fruit fly Drosophila melanogaster to study the interdependence between sensory processing and associative processing on learning performance. We investigated the influence of variations in the physical and predictive properties of color stimuli in several different operant-conditioning procedures on the subsequent learning performance. These procedures included context and stimulus generalization as well as color, compound, and conditional discrimination (colors and patterns). A surprisingly complex dependence of the learning performance on the colors' physical and predictive properties emerged, which was clarified by taking into account the fly-subjective perception of the color stimuli. Based on estimates of the stimuli's color and brightness values, we propose that the different tasks are supported by different parameters of the color stimuli; generalization occurs only if the chromaticity is sufficiently similar, whereas discrimination learning relies on brightness differences.     

The meaning and suitability of various effect sizes for structured Rater x Ratee designs

Four types of analysis are commonly applied to data from structured Rater x Ratee designs. These types are characterized by the unit of analysis, which is either raters or ratees, and by the design used, which is either between-units or within-unit design. The 4 types of analysis are quite different, and therefore they give rise to effect sizes that differ in their substantive interpretations. In most cases, effect sizes based on between-ratee analysis have the least ambiguous meaning and will best serve the aims of meta-analysts and primary researchers. Effect sizes that arise from within-unit designs confound the strength of an effect with its homogeneity. Nonetheless, the authors identify how a range of effect-size types such as these serve the aims of meta-analysis appropriately.