Why Dexamethasone Poorly Penetrates in Brain

Dexamethasone poorly penetrates in brain. A tracer amount of [3H]-dexamethasone administered to adrenalectomized rats or mice is poorly retained by glucocorticoid receptors in brain, while pituitary corticotrophs containing equivalent amounts of these receptors accumulate and retain large amounts of this synthetic steroid. However, adrenalectomized mice with a genetic disruption of the multiple drug resistance (mrd1a) gene have a tenfold increase of [3H]-dexamethasone uptake in brain glucocorticoid target sites reaching levels observed in the pituitary. These data demonstrate that dexamethasone is extruded from brain by the mrd1a-encoded P-glycoproteins. The data support the concept of a pituitary site of action of dexamethasone in blockade of stress-induced ACTH release, which implies that chronic dexamethasone treatment does not replace the endogenous corticosteroids depleted from brain mineralocorticoid (MRs) and glucocorticoid receptors (GRs). Dexamethasone, therefore, causes a profound disturbance in the balance of these two receptor types in hippocampus, which is an unfavourable condition threatening the neuronal integrity of this brain structure through the expression of noxious genes.     

Preview benefit in speaking occurs regardless of preview timing

Speakers access information from objects they will name but have not looked at yet, indexed by preview benefit—faster processing of the target when a preview object previously occupying its location was related rather than unrelated to the target. This suggests that speakers distribute attention over multiple objects, but it does not reveal the time course of the processing of a current and a to-be-named object. Is the preview benefit a consequence of attention shifting to the next-to-be-named object shortly before the eyes move to that location, or does the benefit reflect a more unconstrained deployment of attention to upcoming objects? Using the multiple-object naming paradigm with a gaze-contingent display change manipulation, we addressed this issue by manipulating the latency of the onset of the preview (SOA) and whether the preview represented the same concept as (but a different visual token of) the target or an unrelated concept. The results revealed that the preview benefit was robust, regardless of the latency of the preview onset or the latency of the saccade to the target (the lag between preview offset and fixation on the target). Together, these data suggest that preview benefit is not restricted to the time during an attention shift preceding an eye movement, and that speakers are able to take advantage of information from nonfoveal objects whenever such objects are visually available.     

Discovering New Ways of Moving: Observational Analysis of Motor Creativity While Dancing Contact Improvisation and the Influence of the Partner

Contact improvisation (CI) is a form of dance based on motor creativity, improvisation and the physical contact between different improvisers dancing together. This will generate different ways of moving and a varied use of motor creativity depending on the dancers involved. This study aims to observe the differences in movement generation depending on the partner by using OSMOS (Observational System of Motor Skills; Castañer & Camerino 2006; Castañer et al., 2009). Four contact improvisers were video‐recorded while dancing in duets. Data were analysed by three observers using Theme Coder software (Magnusson, 1996) for the detection of T‐patterns and the production of event frequency charts. The results show that (1) the motor skills that appear most frequently are the conduction of partners, elevations, spatial level changes and turns; (2) motor creativity is affected by the partner, as there is a reciprocal influence in the dance; and (3) motor creativity is enhanced by interaction with a partner.