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Mind & Brain :: Mind Matters :: November 15, 2011 :: :: Email :: Print Celebrated neuroscientist Michael S. Gazzaniga explains the new science behind an ancient philosophical question By Gareth Cook
After orgasm, activity in the hypothalamus and nucleus accumbens gradually calms down. Illustration: Corbis Scientists have used brain scan images to create the world's first movie of the female brain as it approaches, experiences and recovers from an orgasm. The animation reveals the steady buildup of activity in the brain as disparate regions flicker into life and then come together in a crescendo of activity before gently settling back down again. To make the animation, researchers monitored a woman's brain as she lay in a functional magnetic resonance imaging (fMRI) scanner and stimulated herself.
Image 1 of 8 Hydra Our single-celled ancestors had sophisticated machinery for sensing and responding to the environment.
The synaptic pruning that helps sculpt the adolescent brain into its adult form continues to weed out weak neural connections throughout our 20s. The surprise finding could have implications for our understanding of schizophrenia, a psychological disorder which often appears in early adulthood. As children, we overproduce the connections – synapses – between brain cells. During puberty the body carries out a kind of topiary , snipping away some synapses while allowing others to strengthen. Over a few years, the number of synapses roughly halves, and the adult brain emerges.
The key to pleasant music may be that it pleases our neurons. A new model suggests that harmonious musical intervals trigger a rhythmically consistent firing pattern in certain auditory neurons, and that sweet sounds carry more information than harsh ones. Since the time of the ancient Greeks, we have known that two tones whose frequencies were related by a simple ratio like 2:1 (an octave) or 3:2 (a perfect fifth) produce the most pleasing, or consonant, musical intervals. This effect doesn't depend on musical training – infants and even monkeys can hear the difference. But it was unclear whether consonant chords are easier on the ears because of the way the sound waves combine in the air, or the way our brains convert them to electrical impulses . A new mathematical model presents a strong case for the brain.
The pregenual anterior cingulate cortex ( purple ) may be the seat of self-consciousness in the brain. Image: COURTESY OF W. IRWIN, University of California, San Francisco Feeling embarrassed?
LIVING DOLL: When the body is Barbie's, what happens to the brain? Image: iStock/Andrew Cribb In science fiction and fantasy tales, there is a long running fascination with the idea of dramatically diminishing or growing in stature. In the 1989 classic, Honey, I Shrunk the Kids, Rick Moranis invents a device which accidentally shrinks both his own and the neighbor’s children down to a quarter-of-an-inch tall.
It's less of a fear of the unknown, but we have a semantic memory store, which helps us to make implications about new or novel objects (such as a snake) that we've not seen before. We might not be aware what snakes are, but might make associations by the way they move, or the fact that they are reptiles, or that they have big teeth as potentially scary, based on the way our previous memories are structured (in networks and nodes) where facets can be drawn from. If you think about it, how would you know that a Cobra is scary if youve only seen a Rattlesnake?
I am abruptly inspired, as I noticed the sinus cavities expand, while thinking :wow, I wonder how horrible mine would look, given the chronic sinus problems that my dr. thinks is a figment of my imagination" ... before realizing "Hey, my neurologist got an MRI of my head last Summer! I bet I could actually look." Thanks - I've been meaning to call her anyway. :)
When you experience a new event, your brain encodes a memory of it by altering the connections between neurons. This requires turning on many genes in those neurons. Now, MIT neuroscientists have identified what may be a master gene that controls this complex process. The findings, described in the Dec. 23 issue of Science , not only reveal some of the molecular underpinnings of memory formation — they may also help neuroscientists pinpoint the exact locations of memories in the brain. The research team, led by Yingxi Lin, a member of the McGovern Institute for Brain Research at MIT, focused on the Npas4 gene, which previous studies have shown is turned on immediately following new experiences. The gene is particularly active in the hippocampus, a brain structure known to be critical in forming long-term memories.
MIT postdoc Emile Bruneau has long been drawn to conflict — not as a participant, but an observer. In 1994, while doing volunteer work in South Africa, he witnessed firsthand the turmoil surrounding the fall of apartheid; during a 2001 trip to visit friends in Sri Lanka, he found himself in the midst of the violent conflict between the Tamil Tigers and the Sri Lankan military. Those chance experiences got Bruneau, who taught high school science for several years, interested in the psychology of human conflict. While teaching, he also volunteered as counselor for a conflict-resolution camp in Ireland that brought Catholic and Protestant children together.
How does free will function in the brain? Image courtesy of Flickr user alles-schlumpf If you have, so far, held true to your New Year’s resolutions, I salute you and wish you much success in this noble endeavor. If, however, you have already tossed them aside like scolding squatters in your psyche, do I have a blog post for you.
For one thing, certain brain waves that correlate with heightened attention become more active, according to researchers who have used EEGs, or electroencephalographs, to study the brain’s electrical frequencies. Brain waves that signal less-focused attention, meanwhile, tend to subside. In other words, this is your brain on ads.
Babies who watch TV are more likely to have delayed cognitive development and language at 14 months, especially if they're watching programs intended for adults and older children. We probably knew that 24 and Grey's Anatomy don't really qualify as educational content, but it's surprising that TV-watching made a difference at such a tender age. Babies who watched 60 minutes of TV daily had developmental scores one-third lower at 14 months than babies who weren't watching that much TV. Though their developmental scores were still in the normal range, the discrepancy may be due to the fact that when kids and parents are watching TV, they're missing out on talking, playing, and interactions that are essential to learning and development. This new study, which appeared in the Archives of Pediatric and Adolescent Medicine , followed 259 lower-income families in New York, most of whom spoke Spanish as their primary language at home.
29 July 2011 Last updated at 04:44 ET By Judith Burns Science reporter, BBC News Volunteers wearing EEG caps used a driving simulator Tapping into drivers' brain signals can cut braking distances and avoid car crashes, according to scientists.