Dado el hecho que muchos veteranos de guerra generalmente sufren de recuerdos traumáticos recurrentes después de volver a casa, nuestro sistema de borrado selectivo de recuerdos y una vía rápida e inducible sugiere la existencia de paradigmas moleculares bajo recuerdos traumáticos pueden ser borrados o degradados mientras se preservan otros recuerdos en el cerebro.

Los resultados claramente demuestran que la actividad neural en la zona media prefrontal, como en la zona temporo-parietal, linealmente aumentaron el grado de similitud de comportamiento a un humano por parte del compañero de juego, por ejemplo, mientras el comportamiento más se parecia al de un humano, más participantes del estudio enlazaban regiones corticales asociadas con el estado mental de atribución/mentalización.

Más aún, en un cuestionario posterior, los participantes respondieron que disfrutaron más cuando su compañero mostro actitudes humanas evaluando a los robots como "más inteligentes".

"Hydrogen sulfide is the stinky gas that can kill workers who encounter it in sewers; but when adminstered to mice in small, controlled doses, within minutes it produces what appears to be totally reversible metabolic suppression," says Warren Zapol, MD, chief of Anesthesia and Critical Care at MGH and senior author of the Anesthesiology study. "This is as close to instant suspended animation as you can get, and the preservation of cardiac contraction, blood pressure and organ perfusion is remarkable."

The researchers measured factors such as heart rate, blood pressure, body temperature, respiration and physical activity in normal mice exposed to low-dose (80 ppm) hydrogen sulfide for several hours. They analyzed cardiac function with electrocardiograms and echocardiography and measured blood gas levels. While some mice were studied at room temperature, others were kept in a warm environment - about 98º F - to prevent their body temperatures from dropping.

In all the mice, metabolic measurements such as consumption of oxygen and production of carbon dioxide dropped in as little as 10 minutes after they began inhaling hydrogen sulfide, remained low as long as the gas was administered, and returned to normal within 30 minutes of the resumption of a normal air supply. The animals' heart rate dropped nearly 50 percent during hydrogen sulfide adminstration, but there was no significant change in blood pressure or the strength of the heart beat. While respiration rate also decreased, there were no changes in blood oxygen levels, suggesting that vital organs were not at risk of oxygen starvation.

The mice kept at room temperature had the same drop in body temperature seen in earlier studies, but those in the warm environment maintained normal body temperatures. The same metabolic and cardiovascular changes were seen in both groups, indicating that they did not depend on the reduced body temperature, and analyzing the timing of those changes showed that metabolic reduction actually began before body temperature dropped.

"Producing a reversible hypometabolic state could allow organ function to be preserved when oxygen supply is limited, such as after a traumatic injury," says Gian Paolo Volpato, MD, MGH Anesthesiology research fellow and lead author of the study. "We don't know yet if these results will be transferable to humans, so our next step will be to study the use of hydrogen sulfide in larger mammals."

Los Diatomos, o diatomeas, son algas unicelulares que forma una unica formacion de concha, llamada frustula. Producen cerca de la tercera parte del oxigeno mundial, y son las que en un comienzo de la tierra hicieron posible la aparicion del oxigeno y de la atmosfera en la tierra.