Cognitive function defines performance in objective tasks that require conscious mental effort. Extreme environments, namely heat, hypoxia, and cold can all alter human cognitive function due to a variety of psychological and/or biological processes. The aims of this Focused Review were to discuss; (1) the current state of knowledge on the effects of heat, hypoxic and cold stress on cognitive function, (2) the potential mechanisms underpinning these alterations, and (3) plausible interventions that may maintain cognitive function upon exposure to each of these environmental stressors. The available evidence suggests that the effects of heat, hypoxia, and cold stress on cognitive function are both task and severity dependent. Complex tasks are particularly vulnerable to extreme heat stress, whereas both simple and complex task performance appear to be vulnerable at even at moderate altitudes. Cold stress also appears to negatively impact both simple and complex task performance, however, the research in this area is sparse in comparison to heat and hypoxia. In summary, this focused review provides updated knowledge regarding the effects of extreme environmental stressors on cognitive function and their biological underpinnings. Tyrosine supplementation may help individuals maintain cognitive function in very hot, hypoxic, and/or cold conditions. However, more research is needed to clarify these and other postulated interventions.

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32Probiotic and glutamine supplementation increases tissue Hsp72, but their influence on extracellular 33 Hsp72 (eHsp72) has not been investigated. The aim of this study was to investigate the effect of 34 chronic probiotic supplementation, with or without glutamine, on eHsp72 concentration before and 35 after an ultramarathon. Thirty-two participants were split into three independent groups, where they 36 ingested probiotic capsules (PRO, n = 11), probiotic + glutamine powder (PGLn, n = 10) or no 37 supplementation (CON, n = 13), over a 12-week period prior to commencement of the Marathon des

Action observation activates brain areas involved in performing the same action and has been shown to increase motor learning, with potential implications for neurorehabilitation. Recent work indicates that the effects of action observation on movement can be increased by motor imagery or by directing attention to observed actions. In voluntary imitation, activation of the motor system during action observation is already increased. We therefore explored whether imitation could be further enhanced by imagery or attention. Healthy participants observed and then immediately imitated videos of human hand movement sequences, while movement kinematics were recorded. Two blocks of trials were completed, and after the first block participants were instructed to imagine performing the observed movement (Imagery group, N = 18) or attend closely to the characteristics of the movement (Attention group, N = 15), or received no further instructions (Control group, N = 17). Kinematics of the imitated movements were modulated by instructions, with both Imagery and Attention groups being closer in duration, peak velocity and amplitude to the observed model compared with controls. These findings show that both attention and motor imagery can increase the accuracy of imitation and have implications for motor learning and rehabilitation. Future work is required to understand the mechanisms by which these two strategies influence imitation accuracy.

Background: Approximately 30 000 people undergo major emergency abdominal gastrointestinal surgery annually, and 36 per cent of these procedures (around 10 800) are carried out for emergency colorectal pathology. Some 14 per cent of all patients requiring emergency surgery have a laparoscopic procedure. The aims of the LaCeS (laparoscopic versus open colorectal surgery in the acute setting) feasibility trial were to assess the feasibility, safety and acceptability of performing a large-scale definitive phase III RCT, with a comparison of emergency laparoscopic versus open surgery for acute colorectal pathology. Methods: LaCeS was designed as a prospective, multicentre, single-blind, parallel-group, pragmatic feasibility RCT with an integrated qualitative study. Randomization was undertaken centrally, with patients randomized on a 1 : 1 basis between laparoscopic or open surgery. Results: A total of 64 patients were recruited across five centres. The overall mean steady-state recruitment rate was 1⋅2 patients per month per site. Baseline compliance for clinical and health-related quality-of-life data was 99⋅8 and 93⋅8 per cent respectively. The conversion rate from laparoscopic to open surgery was 39 (95 per cent c.i. 23 to 58) per cent. The 30-day postoperative complication rate was 27 (13 to 46) per cent in the laparoscopic arm and 42 (25 to 61) per cent in the open arm. Conclusion: Laparoscopic emergency colorectal surgery may have an acceptable safety profile. Registration number: ISRCTN15681041 (http://www.controlled-trials.com).