Effect of Sleep Restriction on Decision Making and Inflammation

* hypothesis: sleep restriction in healthy subject trigger alteration of decision making associated with immuno-inflammatory changes * inclusion criterias: healthy subjects, men, under 35 years, BMI\<26, no sleep troubles, intermediate chronotype * design: 12 subjects, longitudinal study 2 days of baseline, 7 night of sleep restriction (4h sleep/night), recovery (1, 2, 3 and 9 normal sleep nights). * parameters: decision making tests, reaction time, wakefulness test, biological parameters (cathecholamines, pro-inflammatory cytokines...), heart rate, blood pressure * control of sleep restriction: continuous polysomnographic survey