Proactive inhibitory control varies with task context

The goal of executive control is to adjust our behaviour to the environment. It involves not only the continuous planning and adaptation of actions but also the inhibition of inappropriate movements. Recently, a proactive form of inhibitory control has been shown, demonstrating that actions can be withheld, in an uncertain environment, thanks to the proactive locking of the mechanism by which motor commands are triggered (e.g. while waiting at traffic lights in a dense pedestrian zone, one will refrain in anticipation of a brisk acceleration when the green light comes on). However, little is known about this executive function and it remains unclear whether the overall amount of inhibitory control can be modulated as a function of the context. Here, we show that the level of this control varies parametrically as a function of the exogenous and endogenous factors setting the task context. We also show that the level of implemented proactive inhibitory control is dynamically readjusted to match the implicit temporal structure of the environment. These observations are discussed in relation to possible underlying functional substrates and related neurological and psychiatric pathologies.     

Double-balloon enteroscopy: preliminary experience in patients with obscure gastrointestinal bleeding or chronic abdominal pain

BACKGROUND AND STUDY AIMS: Even in the era of capsule endoscopy, diseases of the small bowel are sometimes difficult to diagnose, and endoscopic treatment is not possible without surgical laparotomy. The new method of carrying out enteroscopy using a double-balloon technique allows not only diagnostic but also therapeutic endoscopic interventions for lesions in the small bowel. Preliminary experience with this new method is reported here. PATIENTS AND METHODS: Between the end of March 2003 and August 2003, eight patients (four women, four men; mean age 59 +/- 23 years, range 20 - 90) with chronic gastrointestinal bleeding or abdominal pain, or both, underwent enteroscopy using the double-balloon technique. Seven of the patients had been suffering from chronic gastrointestinal bleeding for 56 +/- 49 months (range 3 - 120 months, median 48 months). The lowest hemoglobin levels ranged from 3.6 g/dl to 8.6 g/dl (mean 6.7 +/- 1.7 g/dl), and a mean of 7.6 +/- 5.6 (range 1 - 15) blood units had been transfused. Capsule endoscopy was carried out in six patients, revealing angiodysplasias in three, suspected Crohn's disease in one, fresh blood in the small bowel without a lesion in one, and a focal enanthema in another patient. RESULTS: Enteroscopy with the double-balloon technique was carried out using the oral approach in all patients and additionally with the anal approach in four patients. In two patients with multiple angiodysplasias, it was possible to examine the whole small bowel and to treat the angiodysplasias. All of the capsule endoscopy findings were confirmed; a definite bleeding source was found and treated in two patients with unclear bleeding, and in another patient the real bleeding source was found (not angiodysplasia). The enteroscopy system was easy to handle in all cases. No complications occurred. It was possible to carry out the procedure with the patients under sedoanalgesia. CONCLUSIONS: This new enteroscopy system is easy to handle and seems to be safe. Visualization of the whole small bowel is possible using both the oral and anal approaches. Enteroscopy with the double-balloon technique promises to become a standard method for diagnostic and therapeutic endoscopy of the small bowel without surgical laparotomy.     

A qualitative assessment of injection drug use and harm reduction programmes in Kabul, Afghanistan: 2006-2007

BackgroundThe purpose of this paper was to examine the context of injection drug use in Kabul, Afghanistan among injection drug users (IDUs) utilising and not utilising needle and syringe programmes (NSPs).MethodsFollowing identification of themes from eight focus group discussions, free-lists were used for further exploration with both NSP using (n = 30) and non-NSP using (n = 31) IDUs.Results All participants were male, had been injecting for 5 years (mean), and most (95%) had been refugees in the past decade. Main reasons for sharing syringes were convenience and lack of availability and did not vary based on NSP use. Drug users perceived alienation from the community, evidenced by names used for drug users by the community which convey social stigma and moral judgment. Health risks were the principal stated risk associated with drug use, which was mentioned more frequently by NSP users. Harm reduction services available in Kabul are perceived to be insufficient for those in need of services, resulting in under utilisation. The limited scope and distribution of services was frequently cited both as an area for improvement among NSP using IDU or as a reason not to use existing programmes.ConclusionsWhile some positive differences emerged among NSP-using IDU, the current context indicates that both rapid scale-up and increased variety of services, particularly in the realm of addiction treatment, are urgently needed in this setting.     

Improved Survival Outcomes for Kidney Cancer Patients With Brain Metastases

Background

Brain metastases (BM) occur frequently in patients with metastatic kidney cancer and are a significant source of morbidity and mortality. Although historically associated with a poor prognosis, survival outcomes for patients in the modern era are incompletely characterized. In particular, outcomes after adjusting for systemic therapy administration and International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk factors are not well-known.

Default mode of brain function in monkeys

Human neuroimaging has revealed a specific network of brain regions-the default-mode network (DMN)-that reduces its activity during goal-directed behavior. So far, evidence for a similar network in monkeys is mainly indirect, since, except for one positron emission tomography study, it is all based on functional connectivity analysis rather than activity increases during passive task states. Here, we tested whether a consistent DMN exists in monkeys using its defining property. We performed a meta-analysis of functional magnetic resonance imaging data collected in 10 awake monkeys to reveal areas in which activity consistently decreases when task demands shift from passive tasks to externally oriented processing. We observed task-related spatially specific deactivations across 15 experiments, implying in the monkey a functional equivalent of the human DMN. We revealed by resting-state connectivity that prefrontal and medial parietal regions, including areas 9/46d and 31, respectively, constitute the DMN core, being functionally connected to all other DMN areas. We also detected two distinct subsystems composed of DMN areas with stronger functional connections between each other. These clusters included areas 24/32, 8b, and TPOC and areas 23, v23, and PGm, respectively. Such a pattern of functional connectivity largely fits, but is not completely consistent with anatomical tract tracing data in monkeys. Also, analysis of afferent and efferent connections between DMN areas suggests a multisynaptic network structure. Like humans, monkeys increase activity during passive epochs in heteromodal and limbic association regions, suggesting that they also default to internal modes of processing when not actively interacting with the environment.