Neurobiological model of visuo-spatial cognition in young Williams Syndrome children: measures of dorsal-stream and frontal function

We examine hypotheses for the neural basis of the profile of visual cognition in young children with Williams syndrome (WS). These are: (a) that it is a consequence of anomalies in sensory visual processing; (b) that it is a deficit of the dorsal relative to the ventral cortical stream; (c) that it reflects deficit of frontal function, in particular of fronto-parietal interaction; (d) that it is related to impaired function in the right hemisphere relative to the left. The tests reported here are particularly relevant to (b) and (c). They form part of a more extensive programme of investigating visual, visuospatial, and cognitive function in large group of children with WS children, aged 8 months to 15 years. To compare performance across tests, avoiding floor and ceiling effects, we have measured performance in children with WS in terms of the ‘age equivalence’ for typically developing children. In this paper the relation between dorsal and ventral function was tested by motion and form coherence thresholds respectively. We confirm the presence of a subgroup of children with WS who perform particularly poorly on the motion (dorsal) task. However, such performance is also characteristic of normally developingchildren up to 5 years: thus the WS performance may reflect an overall persisting immaturity of visuospatial processing which is particularly evident in the dorsal stream. Looking at the performance on the global coherence tasks of the entire WS group, we find that there is also a subgroup who have both high form and motion coherence thresholds, relative to the performance of children of the same chronological age and verbal age on the BPVS, suggesting a more general global processing deficit. Frontal function was tested by a counterpointing task, ability to retrieve a ball from a ‘detour box’, and the Stroop-like ‘day-night’ task, all of which require inhibition of a familiar response. When considered in relation to overall development as indexed by vocabulary, the day-night task shows little specific impairment, the detour box shows a significant delay relative to controls, and the counterpointing task shows a marked and persistent deficit in many children. We conclude that frontal control processes show most impairment in WS when they are associated with spatially directed responses, reflecting a deficit of fronto-parietal processing. However, children with WS may successfully reduce the effect of this impairment by verbally mediated strategies. On all these tasks we find a range of difficulties across individual children and a small subset of WS who show very good performance, equivalent to chronological age norms of typically developing children. Neurobiological models of visuo-spatial cognition in children with WS p.4 Overall, we conclude that children with WS have specific processing difficulties with tasks involving frontoparietal circuits within the spatial domain. However, some children with WS can achieve similar performance to typically developing children on some tasks involving the dorsal stream, although the strategies and processing may be different in the two groups.

Female choice in the red mason bee, Osmia rufa (L.) (Megachilidae)

Females are often thought to use several cues and more than one modality in selection of a mate, possibly because they offer complementary information on a mate's suitability. In the red mason bee, Osmia rufa, we investigated the criteria a female uses to choose a mating partner. We hypothesized that the female uses male thorax vibrations and size as signs of male viability and male odor for kin discrimination and assessment of genetic relatedness. We therefore compared males that had been accepted by a female for copulation with those rejected, in terms of their size, their immediate precopulatory vibrations (using laser vibrometry), the genetic relatedness of unmated and mated pairs (using microsatellite markers) and emitted volatiles (using chemical analyses). Females showed a preference for intermediate-sized males that were slightly larger than the modal male size. Furthermore, male precopulatory vibration burst duration was significantly longer in males accepted for copulation compared with rejected males. Vibrations may indicate vigor and assure that males selected by females are metabolically active and healthy. Females preferentially copulated with males that were genetically more closely related, possibly to avoid outbreeding depression. Volatiles of the cuticular surface differed significantly between accepted and rejected males in the relative amounts of certain hydrocarbons, although the relationship between male odor and female preference was complex. Females may therefore also use differences in odor bouquet to select among males. Our investigations show that O. rufa females appear to use multiple cues in selecting a male. Future investigations are needed to demonstrate whether odor plays a role in kin recognition and how the multiple cues are integrated in mate choice by females.

Estimating the costs of medicalization

Medicalization is the process by which non-medical problems become defined and treated as medical problems, usually as illnesses or disorders. There has been growing concern with the possibility that medicalization is driving increased health care costs. In this paper we estimate the medical spending in the U.S. of identified medicalized conditions at approximately 77 billion in 2005, 3.9% of total domestic expenditures on health care. This estimate is based on the direct costs associated with twelve medicalized conditions. Although due to data limitations this estimate does not include all medicalized conditions, it can inform future debates about health care spending and medicalization.

Sequencing and its consequences:Path dependence and the relationships between genetics and medicalization

Both advocacy for and critiques of the Human Genome Project assume a self-sustaining relationship between genetics and. medicalization. However, this assumption ignores the ways in which the meanings of genetic research are conditional on its position in sequences of events. Based, on analyses of three conditions for which at least one putative gene or genetic marker has been identified, this article argues that critical junctures in the institutional stabilization of phenotypes and the mechanisms that sustain such classifications over time configure the practices and meanings of genetic research. Path dependence is critical to understanding the lack of consistent fit between genetics and medlcalization.

The social construction of illness:Key insights and policy implications.

The social construction of illness is a major research perspective in medical sociology. This article traces the roots of this perspective and presents three overarching constructionist findings. First, some illnesses are particularly embedded with cultural meaning--which is not directly derived from the nature of the condition--that shapes how society responds to those afflicted and influences the experience of that illness. Second, all illnesses are socially constructed at the experiential level, based on how individuals come to understand and live with their illness. Third, medical knowledge about illness and disease is not necessarily given by nature but is constructed and developed by claims-makers and interested parties. We address central policy implications of each of these findings and discuss fruitful directions for policy-relevant research in a social constructionist tradition. Social constructionism provides an important counterpoint to medicine's largely deterministic approaches to disease and illness, and it can help us broaden policy deliberations and decisions.

The shifting engines of medicalization

Social scientists and other analysts have written about medicalization since at least the 1970s. Most of these studies depict the medical profession, interprofessional or organizational contests, or social movements and interest groups as the prime movers toward medicalization. This article contends that changes in medicine in the past two decades are altering the medicalization process. Using several case examples, I argue that three major changes in medical knowledge and organization have engendered an important shift in the engines that drive medicalization: biotechnology (especially the pharmaceutical industry and genetics), consumers, and managed care. Doctors are still gatekeepers for medical treatment, but their role has become more subordinate in the expansion or contraction of medicalization. Medicalization is now more driven by commercial and market interests than by professional claims-makers. The definitional center of medicalization remains constant, but the availability of new pharmaceutical and potential genetic treatments are increasingly drivers for new medical categories. This requires a shift in the sociological focus examining medicalization for the twenty-first century.