Collège de France

About: Collège de France is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 6541 authors who have published 11983 publications receiving 648742 citations. The organization is also known as: College de France.

Pain modulating and reward systems: A single brain mechanism?

Abstract: The hypothesis that brain rewarding and pain modulating systems could involve a common opiate system, identically blocked by naloxone, has been tested in three experiments. The preferences or aversions for sapid solutions in rats have been employed as reliable measures of responses to rewarding or nociceptive stimulations. In the first experiment, it was shown that the spontaneous aversion to a quinine HCl solution was enhanced when rats were offered the solution 30 min after naloxone at a dose of 1 mg/kg. The same enhanced aversion was observed in the second experiment towards a sweet solution previously made aversive through a conditioned taste aversion paradigm. In the third experiment, by using two different procedures and saccharin or glucose solutions, it was found that naloxone acutely abolished the preference for sweet solutions versus water in rats. It is concluded that: (1) the enhancement by naloxone of the aversion to a sapid solution, similar to the naloxone induced hyperalgesia, allows to assimilate this aversion to other responses to nociceptive stimulations; (2) this suggests that, like other responses to nociceptive stimulations, this aversion is normally attenuated through the release of brain or pituitary opiates; (3) the suppressant effect of naloxone upon both this attenuation of aversion and a preference for a sapid solution supports the notion of a biochemical and functional community between rewarding and pain modulating systems.

Limits on Galactic dark matter with 5 years of EROS SMC data

Abstract: Five years of EROS data towards the Small Magellanic Cloud have been searched for gravitational microlensing events, using a new, more accurate method to assess the impact of stellar blending on the efficiency. Four long-duration candidates have been found which, if they are microlensing events, hint at a non-halo population of lenses. Combined with results from other EROS observation programs, this analysis yields strong limits on the amount of Galactic dark matter made of compact objects. Less than 25% of a standard halo can be composed of objects with a mass between 2 10^-7 Msol and 1 Msol at the 95% C.L.

Specific and common brain regions involved in the perception of faces and bodies and the representation of their emotional expressions

Abstract: Many studies provide support for the role of the fusiform gyrus in face recognition and its sensitivity to emotional expressions. Recently, category-specific representation was also observed for neutral human bodies in the middle temporal/middle occipital gyrus (extrastriate body area) but it is not clear whether this area is also sensitive to emotional bodily expressions. Besides these areas, other regions that process the affective information carried by the face and the body may be common and/or specific to the face or the body. To clarify these issues we performed a systematic comparison of how the whole brain processes faces and bodies and how their affective information is represented. Participants categorized emotional facial and bodily expressions while brain activity was measured using functional magnetic resonance imaging. Our results show that, first, the amygdala and the fusiform gyrus are sensitive to recognition of facial and bodily fear signals. Secondly, the extrastriate body area-area V5/MT is specifically involved in processing bodies without being sensitive to the emotion displayed. Thirdly, other important areas such as the superior temporal sulcus, the parietal lobe and subcortical structures represent selectively facial and bodily expressions. Finally, some face/body differences in activation are a function of the emotion expressed.

Resolved imaging of extra-solar planets with future 10-100km optical interferometric arrays

Abstract: In the recent years, interferometric arrays of optical telescopes have reached sizes of the order of 100m, but they have yet to produce high-resolution images. The analysis of image formation now shows that such images are obtainable directly in the recombined focal plane, if there are enough telescopes. Resolved images of extra-solar planets are in principle obtainable with 10km ground-based arrays.