dilluns, 31 d’octubre de 2011

Redes 108: El cerebro construye la realidad

Redes 108: “El cerebro construye la realidad” //  Fecha de emisión: 30/10/11.



Solemos pensar que nuestra percepción del mundo es mucho más completa de lo que es en realidad. Sentimos que registramos lo que pasa en nuestro entorno al igual que una cámara de vídeo, pero lo que sucede es muy distinto.

Eduard Punset viajó a Mallorca para entrevistar a algunos de los neurocientíficos más destacados del mundo que se habían reunido en el undécimo Congreso Internacional de Neurociencia Cognitiva. En este capítulo de Redes, Kia Nobre, neurocientífica de la Universidad de Oxford, nos explica algunos de los recursos que utiliza el cerebro para hacerse una idea de lo que sucede en su entorno.

diumenge, 30 d’octubre de 2011

"Facial Expressions Develop in the Womb" Life Science

Life Science // by Wynne Parry, LiveScience Senior Writer // Photo credit Nadja Reissland // 07 September 2011

Before he or she is born, a fetus begins to move his or her face — parting lips, wrinkling a nose or lowering a brow for example — making movements that, when combined, will one day assemble expressions we all recognize in one another. A new study has shown that, as the fetus develops, these facial motions become increasingly complex.



While it was known that fetuses could form expressions while in the womb, this study tracked facial movements over time. "What we have found for the first time is you can look at the progression of the complexity of the movements," said lead study researcher Nadja Reissland, a senior lecturer at the University of Durham in the United Kingdom.

Before he or she is born, a fetus begins to move his or her face — parting lips, wrinkling a nose or lowering a brow for example — making movements that, when combined, will one day assemble expressions we all recognize in one another. A new study has shown that, as the fetus develops, these facial motions become increasingly complex.

By capturing images of two fetuses periodically from 24 to about 35 weeks of gestation, the researchers watched individual, unrelated movements progress to complex combinations, associated with recognizable facial expressions. In addition to tracking 19 total facial movements, the study focused on sets of movements associated with two expressions, one associated with crying, the other laughing. Over time, the movements associated with these began to appear in more complex combinations. They used 4-D ultrasound images, which resemble video, to track the facial motions of twofemale fetuses.

At 24 weeks, fetuses were more likely to make a single movement, like a widening of the lips for example, all by itself. Then, as the weeks passed, they began combining the movements, putting, say, a lip widening movement with a nose wrinkle. By about 35 weeks, combinations of three and four movements associated with the two expressions had surpassed single or double movements. A similar trend occurred when the researchers looked at all 19 movements.

Reissland pointed out that these facial movements don't mean the fetuses were experiencing emotion. We can see the expressions which we can recognize; we can't say whether the fetus has emotion," she said. "They [don't] have yet the cognition necessary to have the emotions."

Rather, these motions are likely a form of practice, as the fetuses prepare to enter the social world, where they must form bonds with others. Fetuses also suck their thumbs in the womb and make breathing motions, both precursors for important activities once they are born, she said.

For future research, Reissland is interested in looking for other fetal facial expressions associated with anger, smiling and sadness. This study appeared Aug. 31 in the journal PLoS ONE.

Source: http://www.livescience.com/15939-fetus-facial-expressions.html

"Study: Botox Users Have Trouble Reading Emotions in Others" TIME

We all know that Botox injections paralyze facial muscles — which is why it's used between the brows to iron out frown lines — and can therefore make users appear less emotional. Now a new study finds that the cosmetic toxin may also make recipients less able to read the emotions of others.

TIME Heatlthland // By MEREDITH MELNICK // Monday, April 25, 2011

Social psychologists say we identify emotions in part by mimicking each other's facial expressions. "When you mimic, you get a window into their inner world," said lead researcher David Neal, a psychology professor at University of Southern California, in a statement. "When we can't mimic, as with Botox, that window is a little darker."
For the new study, researchers conducted two experiments: the first involved 31 women who had received either Botox or Restylane, a dermal filler that smoothes wrinkles but doesn't affect facial movement, in Los Angeles (where better to conduct a study on cosmetic procedures?). In a second experiment, 56 women and 39 men were given a topical facial gel that functioned as an "anti-Botox," by augmenting signals from facial muscles. All participants were asked looked at a series of faces on a computer screen and identify the displayed emotions.
The researchers found that compared with the Restylane-treated control group, the women who got Botox were less able to read emotions based on facial expression. Meanwhile, the participants who got the gel were better than the others at perceiving emotions.
Past research has suggested that muscle-paralyzing treatments also hinder people from feeling their own emotions — which could potentially interfere with their ability to empathize. USA Today reported:
"A similar study published last year in the journal Emotion said Botox injections may decrease a person's ability to feel emotions. That study, conducted at Columbia University, compared Botox and Restylane in 68 people. Its lead author, psychologist Joshua Davis, hasn't seen the new study but says the finding "would suggest that facial expression is an integral component of what we consider our emotional experience. Certainly the concept is one that fits with the research we did."
"Human communication can be a very subtle thing," Neal said. "When you eliminate a slice of information — whether by communicating through e-mail and Twitter or by paralyzing your own facial muscles — it can be the difference between successful communication and failure."

Source: http://healthland.time.com/2011/04/25/study-botox-users-have-trouble-reading-emotions-in-others/




dijous, 20 d’octubre de 2011

Interview with Antonio Damasio

Dr. Antonio Damasio is a renowned neuroscientist who direct's the USC Brain and Creativity Institute. Before that he was the Head of Neurology at the University of Iowa Hospitals and Clinics. His research focuses on the neurobiology of mind and behavior, with an emphasis on emotion, decision-making, memory, communication, and creativity.

His research has helped describe the neurological origins of emotions and has shown how emotions affect cognition and decision-making. He is the author of a number of books, including "Self Comes to Mind: Constructing the Conscious Brain," which will be published in November, 2010. Dr. Damasio is also the 2010 winner of the Honda Prize, one of the most important international awards for scientific achievement.

http://bigthink.com/antoniodamasio


Parts:

  • How Memory Works
  • "Consciousness" Is How We Know We Exist
  • How Our Brains Build Our Autobiographies
  • How Our Brains Feel Emotion
  • The Interconnectedness of Our Bodies and Our Minds
  • How Much Can We Really Control Our Minds?
  • The Brain's System of Checks and Balances

dilluns, 17 d’octubre de 2011

dijous, 13 d’octubre de 2011

"We are not thinking machines; we are feelling machines that think" Antonio Damasio in PBS Documentary "The Secret Life of the Brain"

The Secret Life of the Brain, a David Grubin Production, reveals the fascinating processes involved in brain development across a lifetime. The five-part series, informs viewers of exciting information in the brain sciences, introduces the foremost researchers in the field, and utilizes dynamic visual imagery and compelling human stories to help a general audience understand otherwise difficult scientific concepts. A startling new map of the human brain has emerged during the past decade of neuroscience research, contradicting much of what was previously believed. This series tells stories through a mix of personal histories, expert commentary, and animation.



1. The Baby's Brain: Wider than the Sky. A baby's brain is a mystery whose secrets scientists are just beginning to unravel. The mystery begins in the womb -- only four weeks into gestation the first brain cells, the neurons, are already forming at an astonishing rate: 250,000 every minute.

2. The Child's Brain: Syllable from Sound. A child's brain is a magnificent engine for learning. A child learns to crawl, then walk, run and explore. A child learns to reason, to pay attention, to remember, but nowhere is learning more dramatic than in the way a child learns language. As children, we acquire language — the hallmark of being human.

3. The Teenage Brain: A World of Their Own. When examining the adolescent brain we find mystery, complexity, frustration, and inspiration. As the brain begins teeming with hormones, the prefrontal cortex, the center of reasoning and impulse control, is still a work in progress. For the first time, scientists can offer an explanation for what parents already know — adolescence is a time of roiling emotions, and poor judgment.

4. The Adult Brain: To Think by Feeling. The adult brain is the apotheosis of the human intellect, but what of emotion? The study of emotion was once relegated to the backwaters of neuroscience, a testament to the popular conception that what we feel exists outside our brains, acting only to intrude on normal thought. The science has changed: Emotion is now considered integral to our over-all mental health.

5. The Aging Brain: Through Many Lives. At the age of 95, Stanley Kunitz was named poet laureate of the United States. Still writing new poems, still reading to live audiences, he stands as an inspiring example of the brain's ability to stay vital in the final years of our lives. The latest discoveries in neuroscience present a new view of how the brain ages. Overturning decades of dogma, scientists recently discovered that even into our seventies, our brains continue producing new neurons.

dijous, 6 d’octubre de 2011

Identical But Different: Twins and Genes or How Genes Set the Balance Between Autism and Psychosis

Psychology Today // Published on October 5, 2011 by Christopher Badcock, Ph.D. in The Imprinted Brain

In the previous post, I drew attention to two findings for which there is a rising tide of evidence. One is that, although identical twins may inherit identical genes, those genes may be differently expressed in each. The other is the growing realization that mental illnesses like autism or schizophrenia may be caused by such differences in gene expression: by epigenetics rather than simply genetics, so to speak.

Now a new study by a team at the Institute of Psychiatry at King's College, London, has added considerable weight to both propositions by studying 22 sets of identical twins among whom only one of the pair suffered from schizophrenia or bipolar disorder. This was the first genome-wide analysis of epigenetic differences between identical twins discordant for a major psychosis and, as such, strikingly endorses the principal contention of the imprinted brain theory: namely, that such disorders are the result of variations in gene expression, and not simply a question of inheritance.

The study found numerous disease-related differences in gene expression by factors up to 20%, many of them located close to genes previously implicated in psychosis. The top-ranking site was found in the promoter region of a key sialic-acid metabolizing enzyme gene on chromosome 17 (ST6GALNAC1). A rare case of schizophrenia associated with duplication of this part of the same chromosome suggests that over-expression of this gene may be critical for psychosis risk, and members of the same family of enzymes have been associated with schizophrenia and found to play a key role in the development of the forebrain in animal studies. Finally, the fact that the forebrain--and the pre-frontal cortex in particular--have been found to be critical to psychotic cognition suggests a direct mechanism for the role of this gene in schizophrenia, as the authors point out.

The authors also note that some of the genomic regions they discovered showed opposite changes in expression between schizophrenia and bipolar disorder. In other words, some genes whose expression was increased in one disorder were also found to show decreased expression in the other.

This is exactly what the imprinted brain theory predicts for genes implicated in autistic as opposed to psychotic disorders, but at first sight seemingly not within the psychotic spectrum. According to the imprinted brain theory, psychotic and autistic spectrum disorders are opposites caused by conflicting patterns of gene expression. Psychotic spectrum disorders exhibit hyper-mentalism, and autistic ones hypo-mentalism, with enhanced maternal and/or X chromosome gene expression driving the former and enhanced paternal and/or reduced X chromosome gene expression driving the latter. If this is so, how can genes implicated in bipolar disorder or schizophrenia show opposite patterns of expression between themselves? Surely, this is a finding which suggests that the diametric model of mental illness is just too simple--at least where its links to diametrically opposed gene expression are concerned.

Not necessarily. There are three good reasons why, rather than contradicting the diametric model, this finding may in fact corroborate it. The first is the fact that the theory proposes that the diagnosed outcome is a result of an overall imbalance in the expression of genes in the direction predicted. It does not claim that every single gene obeys the antithetic principle. It's a bit like politics. In the government of the genes not every deciding vote will have members of all parties voting consistently. Cross-party voting may occur, but what matters is who gets the majority, and the same goes for the imprinted brain theory: it's the overall outcome that matters.

The second consideration is that from the beginning it has been clear to me at least that within the psychoses there may be a further fundamental dichotomy. This would be between intra-psychic and extra-psychic cognition. As I point out in my book, you can see evidence of hyper-mentalism in both schizophrenia and bipolar disorder if you notice that in the latter case the hyper-active mind-reading is applied to the sufferer's own mind and not--as paradigmatically is the case in paranoia--to the minds of others. The extreme swings in mood symptomatic of bipolar disorder could be seen as pathologically exaggerated equivalents of more normal, but far less extreme mood swings which we all experience when, for example, we say "we feel like X" or "are not in the mood for Y." This is normal intra-psychic mind-reading: interrogating your own mentality about what you wish to do or not to do. In bipolar disorder the same process may become magnified into manic exultation or pathological depression in much the same way that normal reading of other people's minds gets amplified into erotomania or delusions of persecution in paranoia, as I explain at length in The Imprinted Brain.

A third and final consideration lies in the possibility that, as the authors point out, some of the epigenetic changes they measured may have been the result of medication. Anti-psychotic drugs can sometimes mimic the effect of oppositely-acting imprinted genes, and could conceivably activate genes in opposite ways, perhaps explaining the finding.

But however that may be, this landmark study confirms a rapidly emerging consensus among researchers in epigenetics that they can account, both for differences between identical twins, and for their discordant psychiatric illnesses.

Source:
http://www.psychologytoday.com/blog/the-imprinted-brain/201110/identical-different

dilluns, 3 d’octubre de 2011

La cara d'una dona pot provocar el mateix efecte que la cocaïna sobre el cervell dels homes

L'activitat cerebral masculina, observada a través d'un escàner, és igual quan consumeixen cocaïna que quan observen una bonica cara femenina


ARA Barcelona | 03/10/2011 10:52
Els científics confirmen el que tots ens pensàvem: els homes senten un plaer enorme per la bellesa femenina. Ho demostren unes anàlisis fetes en el seu cervell. Concretament, un estudi assegura que la reacció cerebral dels barons en observar la cara d'una dona guapa és igual que la d'aquests mateixos quan consumeixen cocaïna.

Els investigadors de la Universitat de Harvard han descobert que el cervell dels homes als quals se'ls va ensenyar la cara d'una dona atractiva presentaven la mateixa reacció davant els escàners que se'ls practicaven. De fet, l'estudi concreta que presenten activat el mateix "circuit mental de recompensa" que se'ls activa en cas de consum de cocaïna o algunes drogues narcòtiques.

Les cares que, segons els escàners, més activitat produeixen en les cervells masculins són les de dones que tenen un front corbat i prominent acompanyat d'un nas situat prou avall en el conjunt de la cara. Les galtes arrodonides i una petita barbeta també són elements considerats positius per estimular aquesta reposta cerebral de satisfacció.

Font:
http://www.ara.cat/societat/provoca-mateix-efecte-cerebral-cocaina_0_565743516.html