Effects of hunger state on the brain responses to food cues across the life span.

The abundant exposure to food cues in our environment is one of the main drivers of overconsumption. Food evaluation is important for the regulation of food intake by the brain and it's interaction with hunger state. Children are especially susceptible to food cues. Understanding the mechanisms behind this regulation in healthy individuals across the life span can help to elucidate the mechanisms underlying overconsumption and aid the development of future obesity prevention strategies. Few functional neuroimaging studies have been done in children and elderly. Furthermore, it is unknown how hunger state affects neural food cue reactivity in these groups, since this has not been examined consistently. We examined the effects of hunger state and age on the brain responses to low- and high calorie foods. On two mornings, 122 participants (17 children; 38 teens; 36 adults; 31 elderly) performed a food image viewing task while being scanned using fMRI, either fasted or sated. Hunger induced greater activation during high versus low calorie food image viewing than satiety in the bilateral dorsomedial (dmPFC) and in the right dorsolateral prefrontal cortex (dlPFC) across all age groups. There was no significant main effect of age group on high versus low calorie food image viewing and no interaction between age group and hunger state. The greater activation of the dlPFC across all age groups during high calorie food image viewing in a fasted state might reflect increased inhibitory control in response to these foods. This may underlie the ability to resist overconsumption of high calorie foods. Furthermore, increased medial prefrontal cortex activation during hunger might reflect increased reward value of high calorie foods, which declines with satiation. Further studies are needed to better understand these results. Notably, overweight and obese individuals should be included to examine whether these responses are altered by weight status across the life span.

Is smaller workspace a limitation for robot performance in laparoscopy?

PURPOSE: Robot or computer assisted laparoscopic surgeries have overcome several impediments of conventional laparoscopy in pediatric urology. However, in our practice we faced difficulties while performing specific tasks using the da Vinci Surgical System in small cavities. Thus, we objectively evaluated the performance of robot assisted laparoscopic skills in different sizes of workspace. MATERIALS AND METHODS: Seven assessors performed 5 different drills in 7 different sizes of cubic boxes (edge size ranging from 40 to 150 mm) with the da Vinci Surgical System. The drills were developed based on the McGill Inanimate System for Training and Evaluation of Laparoscopic Skills. Assessor performance was evaluated by 2 reviewers for the drill achievement, and time to completion was recorded. A global score was then calculated for each drill in accordance to 1 assessor and 1 box. RESULTS: There were significant collisions while working with the smaller cubes (edges measuring 40 and 45 mm), preventing the surgeon from performing drills. With difficulty, but without collision, the drills were performed in the 50 and 60 mm size cubes. Drills could be accomplished uniformly with ease in the larger cubes (edge 70 mm and greater). CONCLUSIONS: We found that surgeon ability to perform tasks using the da Vinci Surgical System in a small workspace is restricted. This assessment was confirmed by a statistical analysis of the data collected, demonstrating that with common surgical practice using the da Vinci robot workspace has a major impact on surgeon performance.

Advanced da Vinci Surgical System simulator for surgeon training and operation planning.

BACKGROUND: Although patients benefit considerably from minimally invasive surgery, the use of new instruments such as robotic systems is challenging for surgeons, and extensive training is required. METHOD: We developed a computer-based simulator of the da Vinci Surgical System, modelling the robot and designing a new interface. RESULTS: The simulator offers users a two-handed interface to control a realistic model of the da Vinci robot. The simulator can be applied (i) to provide an environment in which to practice simple surgical skills and (ii) to serve as a visualization platform on which to validate port placement and robot pose for operation planning. CONCLUSIONS: Virtual reality is a useful technique for medical training. The simulator is currently in its early stages, but this preliminary work is promising.

Microtechnology applications for medical instrumentation.

The recent progresses in microtechnologies open new possibilities in terms of design, cost reductions, improve performances and, moreover, open new fields of applications in surgical instrumentation. Microtechnology techniques will lead to reconsider the design of medical instrumentation. Surgical tools should not be thought as mechanical systems but as surgical components ("surgical chips") designed with micro-technologies and including microsensors/microactuactors.