Serial correlation in lateralized choices of hand and target

We investigated how lateralized choices of hand and target are influenced by previous behavior. Three monkeys retrieved food pellets following cues indicating the location of available food pellet targets, and the hand that could be used to acquire a target. In pseudo-randomized trials, the monkeys could retrieve food pellet targets only on their right side, only on their left side, or their choice of either right or left side, using only their right hand, only their left hand, or their choice of either hand. We examined separately the patterns of serial correlation in target choices and hand choices. Although individual monkeys showed overall laterality preferences, instead of repeatedly using the preferred hand, we found that the monkeys tended to switch hands in successive trials. This serial correlation in hand choice was stronger and more robust than serial correlation in target choice. Furthermore, the pattern of serial correlation for target choice closely resembled that of serial correlation for hand choice when the animal was allowed to choose both target and hand, but only when the target cue was presented before the hand cue. These results suggest that when cued to choose a hand first, the monkeys tended to make a separate decision as to whether to switch their target choices or not, whereas their decisions to switch hands and targets were linked more tightly if the animal was cued to choose a target first.     

Lesion load in unprotected carotid artery stenting

Introduction  The purpose of the study was to determine the incidence of new ischemic lesions found on diffusion-weighted MR imaging (DWI) in nonselected patients after unprotected carotid artery stent placement. Materials and methods  We retrospectively reviewed a nonrandomized cohort of 197 patients presenting with carotid occlusive disease who underwent unprotected carotid artery stent placement between 2003 and 2006. Mean degree of stenosis was 86.94% ± 9.72. In all patients, DWI was obtained before and 24 h after stent placement. New lesions were evaluated according to size and location. Results  In 59 of 197 patients (29.9%), new ischemic lesions were found on DWI in the vessel dependent area. In 23 of 197 patients (11.7%), new ischemic lesions were found in the vessel independent area. Combined stroke/death rate was 3.63%. Conclusion  In our series of unprotected carotid angioplasty with stent, we found new DWI lesions in 34% of the patients. Further studies should now show in how far protection devices can reduce these lesions. I. Q. Grunwald and P. Papanagiotou contributed equally to this work.     

Constraints on somatotopic organization in the primary motor cortex.

Since the 1870s, the primary motor cortex (M1) has been known to have a somatotopic organization, with different regions of cortex participating in control of face, arm, and leg movements. Through the middle of the 20th century, it seemed possible that the principle of somatotopic organization extended to the detailed representation of different body parts within each of the three major representations. The arm region of M1, for example, was thought to contain a well-ordered, point-to-point representation of the movements or muscles of the thumb, index, middle, ring, and little fingers, the wrist, elbow, and shoulder, as conveyed by the iconic homunculus and simiusculus. In the last quarter of the 20th century, however, experimental evidence has accumulated indicating that within-limb somatotopy in M1 is not spatially discrete nor sequentially ordered. Rather, beneath gradual somatotopic gradients of representation, the representations of different smaller body parts or muscles each are distributed widely within the face, arm, or leg representation, such that the representations of any two smaller parts overlap extensively. Appreciation of this underlying organization will be essential to further understanding of the contribution to control of movement made by M1. Because no single experiment disproves a well-ordered within-limb somatotopic organization in M1, here I review the accumulated evidence, using a framework of six major features that constrain the somatotopic organization of M1: convergence of output, divergence of output, horizontal interconnections, distributed activation, effects of lesions, and ability to reorganize. Review of the classic experiments that led to development of the homunculus and simiusculus shows that these data too were consistent with distributed within-limb somatotopy. I conclude with speculations on what the constrained somatotopy of M1 might tell us about its contribution to control of movement.     

Amino acid composition and betaxanthin formation in fruits from Opuntia ficus-indica

In contrast to earlier reports high levels of taurine (2-aminoethanesulfonic acid) were found in fruit juices of three cultivars of Opuntia ficus-indica (L.) Mill. Whereas the occurrence of taurine in plant tissue was thought to be restricted to algae, fungi, and the endosperm of some higher plants, prickly pear proved to be a rich source of dietary taurine. Using L-taurine as the amino compound, a new betaxanthin was synthesized by partial synthesis. On the basis of chemical and spectral evidence its structure was determined to be the taurine-immonium-conjugate of betalamic acid. Also betalamic acid could be detected in yellow and orange coloured cultivars of Opuntia ficus-indica for the first time. In spite of the high levels of L-taurine accompanied by the occurrence of betalamic acid, the corresponding betaxanthin could not be detected in the fruit tissue.     

Definition of severe mental retardation in school-age children: Findings of an epidemiological study

Summary Data from a survey of school-age children in Mannheim are used to test the hypothesis that two forms of mental retardation — the pathological and the subcultural — can be differentiated on the basis of intelligence tests. The findings indicate that this dichotomy is an over-simplification, since frequency of neurological and other organic impairments is inversely related to intelligence level over a fairly wide range. The best cut-off point for screening purposes, in discriminating between severe or moderately severe retardation (usually pathological), on the one hand, and mild retardation (usually subcultural), on the other, corresponds roughly to IQ 50. Use of higher thresholds tends to increase misclassification and to yield less reliable prevalence rates. Classification of children in the IQ-range 50–70 as mentally handicapped (severely or moderately mentally retarded) appears to be subject to social-class bias, and hence could be selectively disadvantageous for children from lower social-status families. can walk, at best, only with some help.     

Taraxacum--a review on its phytochemical and pharmacological profile

The genus Taraxacum is a member of the family Asteraceae, subfamily Cichorioideae, tribe Lactuceae and widely distributed in the warmer temperate zones of the Northern Hemisphere. The perennial weed has been known since ancient times for its curative properties and has been utilized for the treatment of various ailments such as dyspepsia, heartburn, spleen and liver complaints, hepatitis and anorexia. However, its use has mainly been based on empirical findings. This contribution provides a comprehensive review of the pharmacologically relevant compounds of Taraxacum characterized so far and of the studies supporting its use as a medicinal plant. Particular attention has been given to diuretic, choleretic, anti-inflammatory, anti-oxidative, anti-carcinogenic, analgesic, anti-hyperglycemic, anti-coagulatory and prebiotic effects. Finally, research needs such as quantification of individual Taraxacum constituents and assessment of their pharmacological activities in humans have briefly been outlined.