Interference and facilitation in spatial working memory: Age-associated differences in lure effects in the n-back paradigm.

Working memory (WM) declines prominently during normal aging. The mechanisms underlying this decline are not fully understood. The authors analyzed performance on 2 versions of a 2-back spatial WM task to assess younger and older adults' responses to lures (i.e., nontarget items that match an item earlier in the sequence but not at the current target lag). Results demonstrate lure interference effects that are particularly pronounced among older adults. At the same time, however, older adults showed facilitation for targets. Taken together, these findings suggest that the contribution of familiarity signals to WM performance increases during normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dyadic drumming across the lifespan reveals a zone of proximal development in children.

Many social interactions require the synchronization—be it automatically or intentionally—of one's own behavior with that of others. Using a dyadic drumming paradigm, the authors delineate lifespan differences in interpersonal action synchronization (IAS). Younger children, older children, younger adults, and older adults in same- and mixed-age dyads were instructed to drum in synchrony with their interaction partner at a constant, self-chosen tempo. Adult-only dyads showed the highest and children-only the lowest levels of IAS accuracy. It is important to note that children improved reliably in IAS accuracy when paired with older partners. The observed age-related differences in IAS accuracy remained reliable after statistically controlling for individual differences in the ability to synchronize to a metronome and for between-dyad differences in tempo. The authors conclude that IAS improves from middle childhood to adulthood and that adult interaction partners may facilitate its development. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Working memory plasticity in old age: Practice gain, transfer, and maintenance.

Adult age differences in cognitive plasticity have been studied less often in working memory than in episodic memory. The authors investigated the effects of extensive working memory practice on performance improvement, transfer, and short-term maintenance of practice gains and transfer effects. Adults age 20-30 years and 70-80 years practiced a spatial working memory task with 2 levels of processing demands across 45 days for about 15 min per day. In both age groups and relative to age-matched, no-contact control groups, we found (a) substantial performance gains on the practiced task, (b) near transfer to a more demanding spatial n-back task and to numerical n-back tasks, and (c) 3-month maintenance of practice gains and near transfer effects, with decrements relative to postpractice performance among older but not younger adults. No evidence was found for far transfer to complex span tasks. The authors discuss neuronal mechanisms underlying adult age differences and similarities in patterns of plasticity and conclude that the potential of deliberate working memory practice as a tool for improving cognition in old age merits further exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in components of reaction time distributions and their relations to working memory and intelligence.

The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., τ in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonic doppler technique for microvascular bypass (author's transl)

Following an operative microvascular extraintracranial bypass, 50 patients were re-examined by the ultrasonic Doppler technique. The findings were compared with the results achieved by post-operative angiography. This examination of the patency of extraintracranial anastomoses with the ultrasonic Doppler technique can be conducted on an outpatient basis, is noninvasive and can be frequently repeated. It has a high degree of accuracy (96%). In addition, there were indications that, in certain areas, a gauge could be established for the function of the anastomosis by comparing the amplitude indices from the bypass and the afferent vessels. Key-words: Ultrasonic Doppler technique - microvascular bypass - cerebral blood flow - cerebrovascular disorders     

Modified approach for the selective treatment of temporal lobe epilepsy: transsylvian-transcisternal mesial en bloc resection

1. Intracerebronventricular (i.c.v.) injection of gamma-mangostin (10-40 nmol/mouse), a major compound of the fruit hull of Garcinia mangostana Lin., like ketanserin (10, 20 nmol/mouse, i.c.v.) inhibited 5-fluoro-alpha-methyltryptamine (5-FMT) (45 mg kg(-1), i.p.)-induced head-twitch response in mice in the presence or absence of citalopram (a 5-hydroxytryptamine (5-HT)-uptake inhibitor). 2. Neither the 5-FMT- nor the 8-hydroxy-2-(di-n-propylamino)tetralin (5-HT1A-agonist)-induced 5-HT syndrome (head weaving and hindlimb abduction) was affected by gamma-mangostin or ketanserin. 3. The locomotor activity stimulated by 5-FMT through the activation of alpha1-adrenoceptors did not alter in the presence of gamma-mangostin. 4. 5-HT-induced inositol phosphates accumulation in mouse brain slices was abolished by ketanserin. Gamma-mangostin caused a concentration-dependent inhibition of the inositol phosphates accumulation. 5. Gamma-mangostin caused a concentration-dependent inhibition of the binding of [3H]-spiperone, a specific 5-HT2A receptor antagonist, to mouse brain membranes. 6. Kinetic analysis of the [3H]-spiperone binding revealed that gamma-mangostin increased the Kd value without affecting the Bmax value, indicating the mode of the competitive nature of the inhibition by gamma-mangostin. 7. These results suggest that gamma-mangostin inhibits 5-FMT-induced head-twitch response in mice by blocking 5-HT2A receptors not by blocking the release of 5-HT from the central neurone. Gamma-mangostin is a promising 5-HT2A receptor antagonist in the central nervous system.     

On the specificity of face cognition compared with general cognitive functioning across adult age.

Face cognition is considered a specific human ability, clearly differentiable from general cognitive functioning. Its specificity is primarily supported by cognitive-experimental and neuroimaging research, but recently also from an individual differences perspective. However, no comprehensive behavioral data are available, which would allow estimating lifespan changes of the covariance structure of face-cognition abilities and general cognitive functioning as well as age-differences in face cognition after accounting for interindividual variability in general cognition. The present study aimed to fill this gap. In an age-heterogeneous (18–82 years) sample of 448 adults, we found no factorial dedifferentiation between face cognition and general cognition. Age-related differences in face memory were still salient after taking into account changes in general cognitive functioning. Face cognition thus remains a specific human ability compared with general cognition, even until old age. We discuss implications for models of cognitive aging and suggest that it is necessary to include more explicitly special social abilities in those models. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Normal aging dampens the link between intrusive thoughts and negative affect in reaction to daily stressors.

We charted daily variations in intrusive thoughts to gain access to adult age differences in affective reactivity to daily stressors. On 100 days, 101 younger and 103 older adults reported stressors, intrusive thoughts, and negative affect. Although increments in intrusive thoughts were similar in both age groups on days with stressors, older adults' negative affect increased less than younger adults' on such days. In addition, (a) levels of intrusive thoughts and negative affect across study time were positively associated; (b) days with increased thoughts were days with increased negative affect; and (c) experiencing above-average intrusive thoughts about stressors strengthened affective reactions to stress. Relative to younger adults, all three associations were reduced in older adults. We tentatively conclude that normal aging dampens the stress-induced link between intrusive thoughts and affect. This dampening may contribute to preserved affective well-being and reduced affective reactivity to daily stress in old age. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A theoretical framework for the study of adult cognitive plasticity.

Does plasticity contribute to adult cognitive development, and if so, in what ways? The vague and overused concept of plasticity makes these controversial questions difficult to answer. In this article, we refine the notion of adult cognitive plasticity and sharpen its conceptual distinctiveness. According to our framework, adult cognitive plasticity is driven by a prolonged mismatch between functional organismic supplies and environmental demands and denotes the brain's capacity for anatomically implementing reactive changes in behavioral flexibility (i.e., the possible range of performance and function). We distinguish between 2 interconnected but distinct cognitive outcomes of adult cognitive plasticity: alterations in processing efficiency and alterations in representations. We demonstrate the usefulness of our framework in evaluating and interpreting (a) increments in frontal brain activations in the course of normal aging and (b) the effects of cognitive training in adulthood and old age. Finally, we outline new research questions and predictions generated by the present framework and recommend design features for future cognitive-training studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of angiogenesis and microcirculation of high-grade glioma: an intravital multifluorescence microscopic approach in the athymic nude mouse

The current study follows angiogenesis and microcirculatory changes associated with malignant glioma growth by means of an intravital fluorescence microscopic approach, which allows for the direct and continuous visualization of the glioma microvasculature and its quantitative analysis. Fluorescently labeled C6 rat glioma cells (5 x 10(5)) were implanted into dorsal skinfold chamber preparations of athymic nude mice. Glioma growth, vascularization, microhemodynamics, vascular permeability, and leukocyte-endothelial cell interactions were simultaneously followed over a 22-day observation period using intravital epiillumination microscopy and a multifluorescent labeling technique. Analysis of the process of glioma vascularization revealed three stages with distinct microvascular characteristics: avascular stage (days 0 to 6), lag of glioma growth but initial glioma-induced angiogenesis within the host tissue in peritumoral areas; early vascular stage (days 6 to 14), glioma cell proliferation associated with a spatially homogeneous development of a glioma microvasculature; and late vascular stage (days 14 to 22), exponential tumor growth and expansion (> 400 mm3) with high vascular densities in the peritumoral region and reduced vascularization (microvascular perfusion) in the glioma center. Within the center, the functional vessel length per area correlated inversely with glioma size (P < 0.01). In the peritumoral region, functional vessel length per area was independent of glioma size, indicating persistent, high angiogenic activity throughout the observation period. Thus, the microvasculature of mature gliomas revealed a microvascular zonal division with a progressive reduction of the functional vessel length per area within the tumor center. The perfusion failure of individual microvessels within the glioma center was partly compensated by an increase of diameters (P < 0.05), and thus by an increase of blood flow in these functional microvessels (P < 0.05) over time. Histologic analysis demonstrated both expanding and infiltrating growth patterns, as well as focal necroses on day 22. These are the first data from repeated in vivo analysis of glioma growth, vascularization, and microcirculation.