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11 April 2012

Personality, Habits of Thought and Gender Influence How We Remember



We all have them -- positive memories of personal events that are a delight to recall, and painful recollections that we would rather forget. A new study reveals that what we do with our emotional memories and how they affect us has a lot to do with our gender, personality and the methods we use (often without awareness) to regulate our feelings.
The study appears in Emotion, a journal of the American Psychological Association.
"We're looking at traits that are associated with the way that people process the emotional world and the way that they respond to it," said University of Illinois psychology professor Florin Dolcos, who conducted the study with postdoctoral researcher Sanda Dolcos and University of Alberta postdoctoral researcher Ekaterina Denkova. "We wanted to look not only at how personality traits might influence what and how people remember, but also to examine how that impacts their (subsequent) emotional state."
Previous studies of personality and its relationship to autobiographical memory have tended to focus only on women and only on negative memories, Florin Dolcos said. They do this because women are more likely than men to be diagnosed with emotional disorders such as depression or anxiety, which are associated with an increased focus on negative emotions.
Previous studies have found that people with high neuroticism -- the tendency to focus on negative emotions, particularly in times of stress -- also "are more disposed to become ill with affective disorders like depression and anxiety-related problems," Dolcos said. But these studies have not looked at differences between men and women, the relationship between positive and negative memories, the frequency with which individuals recall specific memories and the vividness of their memories, he said.
Nor have most such studies examined the strategies people use to regulate their emotions when calling to mind positive and negative autobiographical memories. Such strategies include suppression (trying to blunt or hide negative emotions) and reappraisal (trying to adopt a new perspective on unpleasant memories).
The new study examined all these variables, and the findings offer a first hint of the complex interplay of factors that contribute to mood in healthy young men and women.
The researchers used questionnaires and verbal cues to assess personality and to elicit more than 100 autobiographical memories in each of 71 participants (38 of them women). Their analysis revealed that both men and women who were high in extroversion (gregarious, assertive, stimulus-seeking) tended to remember more positive than negative life events. Men who were high in neuroticism tended to recall a greater proportion of negative memories than men who were low in neuroticism, while women who were high in neuroticism tended to return to the same negative memories again and again, a process called rumination.
Rumination is known to be associated with depression, Florin Dolcos said.
"Depressed people recollect those negative memories and as a result they feel sad," he said. "And as a result of feeling sad, the tendency is to have more negative memories recollected. It's a kind of a vicious circle."
None of the study subjects had been diagnosed with depression or other emotional disorders, but, as might be expected, both male and female participants were likely to experience a lower mood after recalling negative autobiographical memories. (Positive memories generally preceded a more positive mood, but the association was indirect and mediated by extroversion, the researchers reported.)
The most pronounced differences between men and women involved the effects of the emotional strategies they used when recalling negative autobiographical memories. Men who engaged in reappraisal, making an effort to think differently about their memories, were likely to recall more positive memories than their peers, while men who used suppression, trying to tamp down their negative emotional responses, saw no pronounced effect on the recall of positive or negative memories. In women, however, suppression was significantly associated with the recall of negative memories and with a lower mood afterward.
"I think that the most important thing here is that we really need to look concomitantly at sex- and personality-related differences and to acknowledge that these factors have a different impact on the way we record our memories, on what we are doing with our memories, and later, how what we are doing with our memories is impacting our emotional well-being," said Sanda Dolcos.
The findings are instructive for both men and women, she said. Being more outgoing, interrupting rumination and using reappraisal seems to work best for men and women as a strategy for dealing with negative memories and cherishing the positive ones, she said.
Florin and Sanda Dolcos are affiliates of the department of psychology and the Beckman Institute for Advanced Science and Technology at Illinois.

Las mujeres tienen más fantasías sexuales en sus periodos fértiles



  • Seguramente no haya recaído en ello, pero si presta atención, probablemente se de cuenta de que sus fantasía sexuales tienen mucho que ver con los distintos momentos de su ciclo menstrual. Un nuevo estudio acaba de confirmar que las mujeres tienen más fantasías sexuales durante los días fértiles del mes
El trabajo, que ha visto la luz en 'Archives Sexual Behavior' y que ha sido elaborado por científicos de la Universidad de Leethebridge (Canadá) y de la de Queens (Reino Unido) ha contado con la participación de 27 mujeres heterosexuales y solteras, de una media de 21 años y medio, que no estaban usando contraceptivos hormonales.
Samantha Jane Dawson, autora principal del trabajo, reconoce a ELMUNDO.es, "Algunos aspectos de la sexualidad de las mujeres parecen estar sincronizados con los períodos de máxima fertilidad, de tal forma que cuando las probabilidades de concerbir son más elevadas, hay un creciente interés por el sexo y la excitabilidad".
Durante mucho tiempo los investigadores han explorado el papel de las hormonas sexuales en la excitación femenina y masculina. Más recientemente, se han centrado en la menstruación como 'actor' de la excitación y las preferencias de las mujeres... Todos los resultados sugieren que la sexualidad femenina cambia con la ovulación. Nuestra investigación pretendía explorar los cambios en las fantasías sexuales a lo largo de todo el ciclo menstrual", introducen los autores en su ensayo, que aclaran que se centraron en las fantasías porque "éstas no dependen de la disponibilidad de pareja ni de otros factores externos".
A todas las participantes se les pidió que se sometieran a pruebas de orina para establecer el momento de la ovulación, además de rellenar cuestionarios sobre su historia sexual. Como parte del ensayo, completaron un diario electrónico con un cuestionario a lo largo de 30 días en el que se indagaba sobre sus fantasías.
Los datos revelan que, en las participantes, la media de fantasías sexuales fue de 0,77 al día pero en los momentos previos a la ovulación, concretamente los tres días antes, éstas aumentaron hasta 1,3 diarias.
"El objetivo fue examinar si los aspectos de la sexualidad femenina, es decir, la fantasía sexual y la especificidad de la categoría de interés sexual se modificaban en función del ciclo menstrual". Y al parecer sí. De hecho, los datos revelan que en los días más fértiles las mujeres tenían más "presente a los varones durante sus sueños eróticos".
No obstante, el contenido "emocional de los mismos aumentó, mientras que el sexual disminuyó", aclaran los investigadores.
Las mujeres "fantaseaban sobre todo acerca de los hombres, aunque poco más de la mitad de la muestra también informó de fantasías con las mujeres. En la mayoría de estas ensoñaciones participaban personas conocidas como la pareja o un ex novio", reconoce la directora del ensayo.
Además de que las fantasías sexuales fueron significativamente más frecuentes durante la ovulación que durante las fases no fértiles, "el nivel de excitación de las mismas también aumentó de forma significativamente. Estos resultados apoyan otras investigaciones que han sugerido que el pico de fertilidad coincide con el aumento de deseo sexual, excitabilidad y motivación sexual".

**Publicado en "EL MUNDO"

Brain-Injury Data Used to Map Intelligence in the Brain


Scientists report that they have mapped the physical architecture of intelligence in the brain. Theirs is one of the largest and most comprehensive analyses so far of the brain structures vital to general intelligence and to specific aspects of intellectual functioning, such as verbal comprehension and working memory.


Their study, published in Brain: A Journal of Neurology, is unique in that it enlisted an extraordinary pool of volunteer participants: 182 Vietnam veterans with highly localized brain damage from penetrating head injuries.
"It's a significant challenge to find patients (for research) who have brain damage, and even further, it's very hard to find patients who have focal brain damage," said University of Illinois neuroscience professor Aron Barbey, who led the study. Brain damage -- from stroke, for example -- often impairs multiple brain areas, he said, complicating the task of identifying the cognitive contributions of specific brain structures.
But the very focal brain injuries analyzed in the study allowed the researchers "to draw inferences about how specific brain structures are necessary for performance," Barbey said. "By studying how damage to particular brain regions produces specific forms of cognitive impairment, we can map the architecture of the mind, identifying brain structures that are critically important for specific intellectual abilities."
The researchers took CT scans of the participants' brains and administered an extensive battery of cognitive tests. They pooled the CT data to produce a collective map of the cortex, which they divided into more than 3,000 three-dimensional units called voxels. By analyzing multiple patients with damage to a particular voxel or cluster of voxels and comparing their cognitive abilities with those of patients in whom the same structures were intact, the researchers were able to identify brain regions essential to specific cognitive functions, and those structures that contribute significantly to intelligence.
"We found that general intelligence depends on a remarkably circumscribed neural system," Barbey said. "Several brain regions, and the connections between them, were most important for general intelligence."
These structures are located primarily within the left prefrontal cortex (behind the forehead), left temporal cortex (behind the ear) and left parietal cortex (at the top rear of the head) and in "white matter association tracts" that connect them.
The researchers also found that brain regions for planning, self-control and other aspects of executive function overlap to a significant extent with regions vital to general intelligence.
The study provides new evidence that intelligence relies not on one brain region or even the brain as a whole, Barbey said, but involves specific brain areas working together in a coordinated fashion.
"In fact, the particular regions and connections we found support an emerging body of neuroscience evidence indicating that intelligence depends on the brain's ability to integrate information from verbal, visual, spatial and executive processes," he said.
The findings will "open the door to further investigations into the biological basis of intelligence, exploring how the brain, genes, nutrition and the environment together interact to shape the development and continued evolution of the remarkable intellectual abilities that make us human," Barbey said.
The research team also included scientists from Universidad Autónoma de Madrid; Medical Numerics, in Germantown, Md.; George Mason University; the University of Delaware; and the Kessler Foundation, in West Orange, N.J.
The U.S. National Institute of Neurological Disorders and Stroke at the National Institutes of Health provided funding for this research.

Seis ratones 'astronautas' para estudiar la pérdida de masa ósea


La astronauta Nicolle Stott junto al módulo en el que viajaron los ratones. | NASA
La astronauta Nicolle Stott junto al módulo en el que viajaron los ratones. | NASA


Seis ratones han batido el récord de estancia de un animal en la Estación Espacial Internacional (ISS). Los roedores, que participaron en un experimento para investigar los efectos de la ingravidez en los seres vivos, permanecieron 91 días en la plataforma orbital, situada a unos 400 kilómetros de la Tierra. Los resultados de este experimento, centrado en la pérdida de masa ósea, se han publicado en 'PLoS ONE'.
Tres de los roedores fueron modificados genéticamente para que fueran capaces de producir mayor cantidad de la proteína pleiotrofina (PTN), un factor de crecimiento. Los investigadores pretendían averiguar si de esta forma lograban frenar la pérdida de masa ósea en los ratones de cara a la preparación de misiones de larga duración.
Los ratones volaron al espacio a bordo del transbordador 'Discovery' el 28 de agosto de 2009, en el marco de la misión 'Mice Drawer System', de la agencia espacial italiana (ASI). Regresaron el 27 de noviembre, tras permanecer 91 días en la ISS, donde los astronautas midieron los cambios en su masa ósea. Tras volver a la Tierra, el estado de salud de los roedores modificados genéticamente fue comparado con el de los tres compañeros. Según aseguran los autores de este estudio, liderados por Sara Tavella, del Departamento de Oncología, Biología y Genética de la Universidad de Génova, los roedores manipulados perdieron un 3% de masa ósea en la columna vertebral mientras que en los otros tres el descenso fue de un 41,5%.

Debilitamiento de los huesos

Uno de los mayores problemas de salud a los que se enfrentan los astronautas que pasan periodos prolongados en el espacio es la pérdida de masa ósea y muscular. En un ambiente de gravidez cero, el esqueleto apenas desarrolla su función principal de sostener el cuerpo. Los movimientos y el ejercicio se reducen considerablemente durante las estancias en el espacio, provocando un descenso en la masa de los huesos y haciéndolos más frágiles.
Los científicos han observado que la pérdida de masa ósea de los astronautas es similar a la causada por la osteoporosis, una enfermedad que afecta a millones de personas en todo el mundo y que está asociada al envejecimiento.
Para minimizar los efectos de la ingravidez, los astronautas deben realizar ejercicio a diario y tomar suplementos de calcio durante su estancia en la ISS. Pese a ello, pueden llegar a perder entre el 20 y el 30% de masa ósea, un porcentaje difícil de recuperar incluso cuando han regresado a la Tierra.
Los ratones volaron a bordo del 'Discovery' en 2009. | NASA. Los ratones volaron a bordo del 'Discovery' en 2009. | NASA.
La desmineralización ósea fue detectada ya en los primeros astronautas que participaron en las misiones 'Gemini' y 'Apollo', en los años sesenta. Los estudios se siguieron llevando a cabo en el laboratorio Skylab y en misiones de larga duración en la estación espacial rusa MIR. Por ejemplo, se comprobó que los cosmonautas rusos experimentaron una pérdida significativa de masa ósea en la tibia al cabo de un mes en el espacio, que fue aumentando a lo largo de su estancia de seis meses. El tratamiento que se llevó a cabo a su vuelta, durante medio año, fue insuficiente para restablecer la densidad de los huesos que tenían antes de iniciar su misión.
Un estudio más reciente llevado a cabo con 14 astronautas que habían permanecido entre cuatro y seis meses en la ISS reveló que, de media, perdieron cada mes un 0,8% de masa ósea de la columna vertebral y un 1,5% del fémur.

Preparación de largas misiones

En anteriores experimentos, los investigadores observaron que las ratas tampoco recuperan toda la masa ósea perdida durante una estancia en el espacio. Según señalan los autores, los ratones presentan varias ventajas respecto a las ratas para este tipo de experimentos. Tienen un tamaño menor, por lo que las jaulas en las que viajan son más pequeñas y, por tanto, más fáciles de transportar, un aspecto muy importante en cualquier viaje misión debido al reducido espacio disponible. Además, su esqueleto presenta algunas características moleculares y morfológicas similares a las de los humanos.
Los resultados de este estudio con ratones modificados genéticamente servirán para investigar el posible uso de estas proteínas en humanos. El objetivo es reforzar su esqueleto de los astronautas y contrarrestar los efectos de la ingravidez en misiones de larga duración, como un viaje a Marte (que podría durar unos dos años), a un asteroide o estancias prolongadas en la Luna.

**Publicado en "EL MUNDO"

Women Not Getting Enough Exercise; At Risk of Developing Metabolic Syndrome


 A national study shows that women are less likely than men to get at least 30 minutes of exercise per day, resulting in greater odds of developing metabolic syndrome -- a risky and increasingly prevalent condition related to obesity.

A group participants were outfitted with accelerometers that measured daily activity. In their study, slightly more than one in three women had metabolic syndrome, and one in five had symptoms of depression.
"It's pretty striking what happens to you if you don't meet that 30 minutes a day of activity," Cardinal said. "Women in our sample had better health behavior -- they were much less likely to smoke for instance, but the lack of activity still puts them at risk."
Cardinal said depression puts people at more risk of abdominal fat and insulin resistance, and both are risk factors for metabolic syndrome.
"Physical activity has been shown to reduce depression," he said. "So the key message here is to get that 30 minutes of exercise every day because it reduces a great deal of risk factors."
While their study does not address why women were not getting enough exercise, the authors said research shows that physical activity patterns often begin in childhood.
"Research has shown that around ages 5 or 6 these patterns begin," Cardinal said. "Parents tend to be more concerned with the safety of girls, and have more restrictive practices around outdoor time and playtime than with boys."
Loprinzi said this pattern tends to continue into adulthood, and that overall confidence may be a factor.
"Some evidence indicates that women, compared to men, have less confidence in their ability to overcome their exercise-related barriers," Loprinzi said, adding that women also often cite a lack of time to exercise due to child-rearing.
The researchers have a study coming out that may help those time-challenged women. Loprinzi said he and Cardinal found that adults can still enhance their health by accumulating physical activity in short periods throughout the day, such as taking the stairs instead of the elevator or pacing while talking on the phone.


**Published in "SCIENCE DAILY"

More exercise, eating less fat and weight loss programs are in, popular diets are out


"This is great news because studies have shown that even a 5 percent reduction in weight can lead to improved health," says lead author Jacinda M. Nicklas, MD, MPH, MA, a clinical research fellow at Beth Israel Deaconess Medical Center and Harvard Medical School. "With more than a third of Americans now obese and fifty to seventy percent of them trying to lose weight, this is important because the health risks associated with carrying that extra weight are substantial."
Nicklas and colleagues analyzed data from more than 4,000 obese individuals culled from the 2001-2006 National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention to assess the health and nutritional status of adults in the United States.
Individuals included in the study were over 20 years of age with a body mass index of 30 or more 12 months prior to the interview.
Of those surveyed, 2,523 individuals reported trying to lose weight. Forty percent of these said they experienced weight loss of 5 percent or greater, and another 20 percent lost 10 percent or more.
"Those who exercised more and ate less fat were significantly more likely to lose weight," say the authors. "Additionally we found a correlation between joining weight loss programs and greater reported weight loss, which may speak to the importance of structure in a weight loss regimen" says Nicklas. And while those who used prescription weight loss medications also reported weight loss success, this represented only a small number of study participants.
In contrast, the authors found that, "self-reported use of popular diets, liquid diets, nonprescription weight loss pills and diet foods/products were not associated with weight loss."
"It's very encouraging to find that the most of the weight loss methods associated with success are accessible and inexpensive," says senior author Christina Wee, MD, MPH who conducts research on obesity and health disparities as the Co-Director of Research in BIDMC's Division of General Medicine and Primary Care. "There are lots of fad diets out there as well as expensive over-the-counter medications that have not necessarily been proven to be effective, and it is important that Americans discuss product claims with their doctor before trying such products."
This study did not look at the long-term impact of these interventions on an individual's ability to keep the weight off. The authors suggest that future research is needed to identify and address barriers to maintaining weight loss.

**Source: Beth Israel Deaconess Medical Center

Explican cómo una diabetes descontrolada puede deteriorar a largo plazo el cerebro



Un grupo del Centro de Investigación Biomédica (CIBERobn) ha encontrado un vínculo entre el sistema nervioso central y la diabetes tipo 2 o del adulto.
Sus trabajos en modelos animales han permitido demostrar que el hipotálamo, la glándula endocrina que se encarga de liberar las principales sustancias que regulan el hambre y la saciedad, está relacionada con el desarrollo de diabetes.
La inflamación de esta región cerebral, que actúa como centro integrador del sistema nervioso vegetativo y es también responsable de la expresión fisiológica de las emociones, genera resistencia a la insulina, antesala de esta patología.
El hallazgo, que se publica en el último número de la revista «Endocrinology» abre la puerta a potenciales tratamientos farmacológicos contra esta enfermedad en humanos.
El equipo del CIBERobn, dirigido por el doctor Jesús Argente desde el Hospital Niño Jesús de Madrid, partió de esta hipótesis para demostrar el hecho de que la resistencia a la acción de la insulina está estrechamente relacionada con una señalización intracelular incorrecta de la leptina y la insulina, que intervienen en la regulación del apetito.
Estos hallazgos sugieren que el tratamiento farmacológico dirigido a estas vías de señalización para ambas hormonas y el bloqueo de las dianas de inflamación hipotalámicas estudiadas podrían ser de interés para el tratamiento de la resistencia a la acción de la insulina y la diabetes tipo 2.
El hallazgo ayuda también a explicar cómo una diabetes descontrolada puede deteriorar a largo plazo el cerebro y producir daños en la memoria. Estos estudios proporcionan una explicación sobre la prevalencia de deterioro cognitivo en pacientes con desórdenes metabólicos, estableciendo un enlace directo entre la resistencia a la insulina y el daño cerebral. Además, respalda estudios epidemiológicos en los que enfermedades como la obesidad, la hiperinsulemia o la diabetes incrementan el riesgo de desórdenes neurodegenerativos, tales como la enfermedad de alzhéimer.

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