caffeinepig

How The Brain Sorts Babble Into Auditory Streams

Known as "the cocktail party problem," the ability of the brain's auditory processing centers to sort a babble of different sounds, like cocktail party chatter, into identifiable individual voices has long been a mystery. Now, researchers analyzing how both humans and monkeys perceive sequences of tones have created a model that can predict the central features of this process, offering a new approach to studying its mechanisms. The research team--Christophe Micheyl, Biao Tian, Robert Carlyon, and Josef Rauschecker--published their findings in the October 6, 2005, issue of Neuron. For both the humans and the monkeys, the researchers used an experimental method in which they played repetitive triplet sequences of tones of two alternating frequencies. Researchers know that when the frequencies are close together and alternate slowly, the listener perceives a single stream that sounds like a galloping horse. However when the tones are at widely separated frequencies or played in rapid succession, the listener perceives two separate streams of beeps. Importantly, at intermediate frequency separations or speeds, after a few seconds the listeners' perceptions can shift from the single galloping sounds to the two streams of beeps. The researchers could use this phenomenon to explore the neurobiology of perception of auditory streams, because they could explore how perception altered with the same stimulus. In the human studies, Micheyl, working in the MIT laboratory of Andrew Oxenham, asked subjects to listen to such tone sequences and signal when their perceptions changed. The researchers found that the subjects showed the characteristic perception changes at the intermediate frequency differences and speeds. Then, Carlyon, working in Rauschecker's laboratory at Georgetown University Medical Center, recorded signals from neurons in the auditory cortex of monkeys as the same sequences of tones were played to the animals. These neuronal signals could be used to indicate the monkeys' perceptions of the tone sequences. From the data on the monkeys, the researchers developed a model that aimed to predict in humans the change in perception between one or two auditory streams under different frequency separations and tone presentation rates.

我現在終於知道「欣喜若狂」是什麼樣的感覺了....
就像這樣 --->
（好啦...我是美一點啦...  ）
The thing is I take a course, Neuroanatomy, under medical school this semester. We need to dissect human brain in this class and look into each and every tiny structure, nuclei and pathway in three dimensions. It sounds real cool but challenging, especially to those who do not have much medical science background like me. Anyway, I've been pressed since the first class of this semester. I'm even not able to sleep well a day before the class, no mention about taking the exam for it. It was an awful experience. After the exam, I thought I did bad, at least not as good as I expected. I tried not to think about how bad it would be and hypnotized myself to just focus on the next coming one. But............."sometimes you just never know..." I got an email from the professor saying "your grade in exam I is A" .... I can't believe what I just saw....hahahaha..!!!

我忍不住狂笑、搥牆壁、跳來跳去....當天晚上，連作夢都夢到了說....
哇哈哈哈.....Am I good or what??   

上個週末，我作了兩道菜。一道是Carrie的「芝麻炸雞」，另一道是自己做實驗的，因為很來是要吃火鍋，買了火鍋專用的薄牛肉片，但是後來買了太多丸子、魚蛋蝦餃和青菜，吃不下，所以就決定來做點別的....
這一道我想可能是叫做「洋蔥牛肉」吧。 以下是成果: 
I. 芝麻炸雞
                                                                                                                                              

Why Females Are Better Off Choosing Unattractive Mates“Ladies choice” isn’t just a dance routine, it is also a driver of species evolution -- and two UBC researchers may have found a reason why. In a research paper published in today’s (Oct. 7) edition of the prestigious journal Science, UBC zoology professor Sarah Otto and graduate student Arianne Albert propose a model that explains why males in some species have extravagant displays for attracting females, while males in other species look just like females.Many groups of animals, including humans, have an “XY” sex-determining system through which the father determines the sex of the offspring -- the offspring is female if it receives an X chromosome from the father, and vice versa. For these species, the chromosome on which flashy displays is coded will determine whether the sons or the daughters inherit the physical trait.“If the genes coding for flashy displays are on the X, the genes from a sexy dad only appear in his daughters, making them visible to predators without improving their reproductive success, and thus favouring the evolution of preferences for dull males,” says Albert, lead author of the paper. “Females in XY species -- including humans -- should therefore prefer bland males, because they produce more fit daughters.” In other groups of animals (including birds), sex-determination is reversed. Females are ZW and males are ZZ, and therefore sex is decided by which sex chromosome (Z or W) is received from the mother. “In these cases, when display genes are on the Z chromosome, the female is better off choosing a sexy mate, because the dad passes the Z to the sons who are thus more attractive,” says Otto. Source:   University Of British Columbia 
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應該來做一個follow-up的實驗來印證這個研究。
找出美麗明星的爸爸們，看看他們是不是長得很普通...
我爸爸也長的蠻普通的啊，那我怎麼長的........
啊.......那可能變成是我媽的責任了.......
突然覺得好輕鬆喔...因為千錯萬錯都不是我的錯...嘻嘻...

Decision Makers May Be Blind To The Outcome Of Their ChoiceWhen evaluating facial attractiveness, participants may fail to notice a radical change to the outcome of their choice, according to a study by researchers at Lund University, Sweden, and New York University. Equally surprising, the study shows that participants may produce confabulatory reports when asked to describe the reasons behind their choices. The findings appear in the October 7 issue of Science.The authors on this paper are Petter Johansson, a graduate student; Lars Hall, a researcher; Sverker Sikstre, an assistant professor; all from Lund University Cognitive Science; and Andreas Olsson, a graduate student in NYU's Department of Psychology.Researchers showed picture-pairs of female faces to the participants and asked them to choose which face in each pair they found most attractive. In addition, immediately after their choice, they were asked to verbally describe the reasons for choosing the way they did. Unknown to the participants, on certain trials, a card magic trick was used to secretly exchange one face for the other. Thus, on these trials, the outcome of the choice became the opposite of what they intended.
  Researchers showed picture-pairs of  female faces to the participants and asked them to choose which face in each pair they found most attractive. In addition, immediately after their choice, they were asked to verbally describe the reasons for choosing the way they did. Unknown to the participants, on certain trials, a card magic trick was used to secretly exchange one face for the other. Thus, on these trials, the outcome of the choice became the opposite of what they intended. (Photographer: Mark Hanlon)
The researchers measured whether the participants noticed that something went wrong with their choice, both concurrently, during the experimental task, and retrospectively through a post-experimental interview. Less than 10% of all manipulations were detected immediately by the participants, and counting all forms of detection no more than a fifth of all manipulated trials were exposed. The researchers call this effect choice blindness.Theories about decision-making generally assume that we recognize when our intentions and the outcome of our choices do not match up, but this study shows that this assumption is not necessarily correct. By shedding new light on the links between intentions and outcomes, these results challenges both current theories of decision making, and common sense notions of choice and self-knowledge.

Neuron Network Goes Awry, and Brain Becomes an IPod Seven years ago Reginald King was lying in a hospital bed recovering from bypass surgery when he first heard the music. It began with a pop tune, and others followed. Mr. King heard everything from cabaret songs to Christmas carols. "I asked the nurses if they could hear the music, and they said no," said Mr. King, a retired sales manager in Cardiff, Wales."I got so frustrated," he said. "They didn't know what I was talking about and said it must be something wrong with my head. And it's been like that ever since."Each day, the music returns. "They're all songs I've heard during my lifetime," said Mr. King, 83. "One would come on, and then it would run into another one, and that's how it goes on in my head. It's driving me bonkers, to be quite honest."Last year, Mr. King was referred to Dr. Victor Aziz, a psychiatrist at St. Cadoc's Hospital in Wales. Dr. Aziz explained to him that there was a name for his experience: musical hallucinations. Dr. Aziz belongs to a small circle of psychiatrists and neurologists who are investigating this condition. They suspect that the hallucinations experienced by Mr. King and others are a result of malfunctioning brain networks that normally allow us to perceive music. They also suspect that many cases of musical hallucinations go undiagnosed. "You just need to look for it," Dr. Aziz said. And based on his studies of the hallucinations, he suspects that in the next few decades, they will be far more common.Musical hallucinations were invading people's minds long before they were recognized as a medical condition. "Plenty of musical composers have had musical hallucinations," Dr. Aziz said.

Melodies in your mind
Researchers map brain areas that process tues
Dartmouth College Office of Public Affairs • Press Release

Researchers at Dartmouth are getting closer to understanding how some melodies have a tendency to stick in your head or why hearing a particular song can bring back a high school dance. They have found and mapped the area in your brain that processes and tracks music. It's a place that's also active during reasoning and memory retrieval.The study by Petr Janata, Research Assistant Professor at Dartmouth's Center for Cognitive Neuroscience, and his colleagues is reported in the Dec. 13, 2002, issue of Science. Their results indicate that knowledge about the harmonic relationships of music is maintained in the rostromedial prefrontal cortex, which is centrally located, right behind your forehead. This region is connected to, but different from, the temporal lobe, which is involved in more basic sound processing."This region in the front of the brain where we mapped musical activity," says Janata, "is important for a number of functions, like assimilating information that is important to one's self, or mediating interactions between emotional and non-emotional information. Our results provide a stronger foundation for explaining the link between music, emotion and the brain."

(*The orange and red area indicates where Janata and his collegues tracked and mapped musical processing in the brain. The blue and purple areas are also processing music, but these areas did not track the harmonic changes as consistently as the red and orange areas. )
 
Using functional magnetic resonance imaging (fMRI) experiments, the researchers asked their eight subjects, who all had some degree of musical experience, to listen to a piece of original music. The eight-minute melody, composed by Jeffrey Birk, Dartmouth class of '02, when he was a student, moves through all 24 major and minor keys. The music was specifically crafted to shift in particular ways between and around the different keys. These relationships between the keys, representative of Western music, create a geometric pattern that is donut shaped, which is called a torus.

Imaging With Radiotracer FDG in Patients With Mild Cognitive Disorder Has Significantly Higher Accuracy Than Genetic Screening, Says Study in Journal of Nuclear MedicineRESTON, Va.—Positron emission tomography (PET) imaging—with the radiotracer fluorodeoxyglucose (FDG)—is a promising tool in detecting Alzheimer's disease in patients who have mild cognitive impairment (MCI), according to a study reported in the October issue of the Society of Nuclear Medicine's Journal of Nuclear Medicine. "PET imaging with FDG represents one of the most promising tools for diagnosis of Alzheimer's," said Alexander Drzezga, M.D., who is the senior physician with the department of nuclear medicine at the Technical University of Munich in Germany. In fact, using PET imaging with FDG "may be the best indicator for determining which MCI patients are most at risk of developing Alzheimer's," added the lead author of "Prediction of Individual Clinical Outcome in Mild Cognitive Impairment (MCI) by Means of Genetic Assessment and 18F-FDG PET." Mild cognitive impairment (MCI) is a term used to describe a subtle but measurable deterioration of cognitive capabilities, such as memory function. Individuals with MCI are able to function reasonably well in everyday activities, such as managing finances and purchasing items at stores without assistance, but may have difficulty remembering details of conversations, events and upcoming appointments. Patients with MCI do not yet exhibit the criteria for the diagnosis of dementia, but the disorder is seen as a precursor to Alzheimer's disease, which takes years to develop in a person, said Drzezga. Many patients with MCI develop a progressive decline in their thinking abilities over time, and Alzheimer's disease is usually the underlying cause. Alzheimer's is the most common form of dementia among older people; it is a progressive, irreversible brain disorder with no known cause or cure. More than 4.5 million Americans suffer from Alzheimer's and its symptoms of memory loss, confusion, impaired judgment, personality changes, disorientation and loss of language skills. "A high percentage of MCI patients will develop Alzheimer's disease within a year; however, some of these patients will never develop dementia and may even improve with time," said Drzezga. Most MCI patients who showed abnormalities typical of Alzheimer's in their original PET scan developed dementia within 16 months, according to findings from the 30-patient study. Most patients who did not show abnormalities in their original PET scan remained stable, he added. Patients with Alzheimer's show characteristic changes of the cerebral glucose metabolic pattern, with a decrease in affected brain regions, said Drzezga. PET imaging with FDG allows the analysis of regional cerebral glucose metabolism. The study showed that "the assessment of cerebral glucose metabolism actually reflects ongoing pathological changes associated with Alzheimer's disease on a molecular level and that the molecular imaging method PET is capable of depicting subtle changes in the brain of MCI patients before a diagnosis of Alzheimer's based on neuropsychological evaluation is possible," said Drzezga. The study revealed that PET with FDG has a significantly higher accuracy for detection of Alzheimer's than the genetic screening for the APOEe4-risk factor. In addition, using both PET with FDG and the APOEe4-genotype as genetic markers "allowed the definition of subgroups of patients with very high risk and with very low risk," he added. This finding could have implications for risk stratifying MCI patients in therapeutic trials, said Drzezga. "This study implies that PET—and in consequence nuclear medicine—should continue to be strongly involved in the challenging process of Alzheimer's research for early diagnosis as well as for the development and evaluation of new treatment options," he added. Although there is currently no cure for Alzheimer's, new treatments are on the horizon as a result of accelerating insight into the biology of the disease. "It is of increasing importance to identify 'converters' at the earliest possible stage of disease to develop and evaluate new and upcoming treatment options for Alzheimer's," added Drzezga, an SNM member. PET is a safe, effective and painless biological imaging exam that "photographs" or detects the presence and extent of neurological conditions. PET uses very small amounts of radioactive materials that are targeted to specific organs, bones or tissues. Radiotracers (such as FDG) are injected and then detected by a special type of camera that works with computers to provide precise pictures of the area of the body being imaged and molecular images of the body's biological functions. "The combination of molecular imaging with genotype assessment represents the unique opportunity to interpret imaging findings in the context of background information," explained Drzezga. "As we increase our understanding of the human genome, individualized therapy and individualized diagnosis will become increasingly important," he added. "The current study underlines that a genetic disposition does not necessarily represent a determined prognosis, thus, the need for measures that allow the definition of the actual onset of a disease process is apparent. Molecular imaging could play an important role in this context," he stated.

New York Times

The Claim: If Attacked by a Bear, Play Dead 
THE FACTS As bear populations from New Jersey to Yellowstone rebound, so do reports of tense human encounters with them.Common wisdom holds that the way to react, when all else fails, is simple: curl up in a ball and play dead.But that is not always the best idea. Attacks can generally be divided into two groups: predatory and defensive. Each calls for a different strategy.Black and grizzly bears are capable of both types of attack. Those involving grizzlies tend to be defensive, when the animal feels threatened, according to Stephen Herrero, a bear expert at the University of Calgary and the author of "Bear Attacks: Their Causes and Avoidance." Playing dead then lets the bear know you're not a threat and can cause it to back off.Black bears usually flee from humans, but when they do attack the motive tends to be predatory, and playing dead doesn't work. Neither does running away, since bears are much faster than humans.If the bear is after food, it is best to drop it and back away, Mr. Herrero says. If the animal presses, he adds, be aggressive: shout, bang on objects or use pepper spray to scare it off. The National Parks Service and the National Wildlife Federation recommend similar measures.THE BOTTOM LINE Experts do not recommend playing dead if a bear attack appears to be predatory.
Comment:
It's really good to know this fact...Otherwise, I would never have ideas of why the bear still takes me as its predator even if I play dead so much alike...   So, my conclusions are as follows:
When you encounter a bear, 
1. double check if he is a black or grizzly bear, and react in an appropriate way then... (but what if his color is grey?? Should I play dead, run away, scream, cry.....)
2. ask the bear if he has food already....if he has already fed his stomach, then you'd better think ways to excape...make sure he isn't lying...
3. ask the bear how he feels today...if he feels depressed, then you can act just as ferocious as a tiger is, shutting at him to make him even more depressed... (but what if he is in a great mood?? should I just take out two beer mugs and drink heartily with him...try to make him drunk and then run away....??  )
Hmm...good good good....

NewYork Times
Serious Riders, Your Bicycle Seat May Affect Your Love Life 

A raft of new studies suggest that cyclists, particularly men, should be careful which bicycle seats they choose.The studies add to earlier evidence that traditional bicycle saddles, the kind with a narrow rear and pointy nose, play a role in sexual impotence. Some saddle designs are more damaging than others, scientists say. But even so-called ergonomic seats, to protect the sex organs, can be harmful, the research finds. The dozen or so studies, from peer-reviewed journals, are summarized in three articles in September's Journal of Sexual Medicine. In a bluntly worded editorial with the articles, Dr. Steven Schrader, a reproductive health expert who studies cycling at the National Institute for Occupational Safety and Health, said he believed that it was no longer a question of "whether or not bicycle riding on a saddle causes erectile dysfunction."Instead, he said in an interview, "The question is, What are we going to do about it?"The studies, by researchers at Boston University and in Italy, found that the more a person rides, the greater the risk of impotence or loss of libido. And researchers in Austria have found that many mountain bikers experience saddle-related trauma that leads to small calcified masses inside the scrotum.This does not mean that people should stop cycling, Dr. Schrader said. And those who ride bikes rarely or for short periods need not worry.But riders who spend many hours on a bike each week should be concerned, he said. And he suggested that the bicycle industry design safer saddles and stop trivializing the risks of the existing seats.