2009年5月4日星期一

脑电Twitter后续:美国新发明只用思考便可网上发帖

美国新发明只用思考便可网上发帖(图)

 威尔逊通过大脑微型扫描仪用思考向互联网发布电子信息。

  研究人员获大脑探索重要成果,只用思考便能向互联网发布电子信息

  大脑究竟如何“运转”?这个问题长期困扰着人类。由于大脑缺乏“活动部件”,因此通过解剖难以了解它的工作机理。不过,面对迅猛发展的新技术,大脑正不断失去笼罩在它周围的神秘气息。

  用脑发帖

  英国《星期日泰晤士报》3日报道,研究人员亚当·威尔逊上月成为只通过思考向互联网发布电子信息的第一人。威尔逊当时并未精心措词,只是简单地在微型博客Twitter上“写”下与大学体育队有关的一句口号。

  威尔逊当时身处美国威斯康星大学的一个实验室,头戴“绒球帽”。实际上,这个“绒球帽”是一部大脑微型扫描仪。每个“绒球”内都有复杂的微电子结构,用以探测威尔逊大脑工作时产生的微弱电场。

  经过数分钟练习,威尔逊发现自己可以用这部大脑微型扫描仪“想”出电子信息并把它们发送出去。用脑在Twitter上“写”下首句话20分钟后,威尔逊继续让那句普通口号变得不再平凡。他以同样方式“写”道:“我正用大脑来拼写。”

  他上周接受采访时说:“如果当初知道会如此受关注,我会‘写’点更有意义的话。”

  威尔逊希望,这种装置最终能使因病既不能讲话、也无法书写的人仅通过思考就可再度同外界交流。

  最新应用

  如今,针对大脑的一些技术已走出实验室,甚至开始进军商业领域。一些科研人员时下正向一些大公司推销自己的大脑扫描技术,称这些技术能揭示人们内心最深处的想法和欲求。

  英国沃里克大学应用神经学教授杰玛·卡尔弗特就是其中一员。卡尔弗特是神经学营销咨询企业Neurosense创始人,Neurosense的客户包括不少大型跨国企业。公司将为这些企业扫描志愿者大脑,以观察他们对不同品牌和产品作何反应。

  “企业界清楚,在推出的新产品中,多达90%会在1年内失败,即使所有市场调研小组和研究活动均表示它们应该成功,”卡尔弗特说,“研究显示, 这是因为我们大多数购买决定出于下意识,以我们甚至未意识到的‘程序’为基础。大脑扫描可揭示这些‘程序’,就如何营销及改进产品向企业提供更佳意见。”

  刘鹏(新华社供本报特稿)

Our amygdala is more responsive to pleasant words

source: deric bownds

Interesting observations from Herbert et al. Some brain correlates of how we remember pleasant better than unpleasant reading content. Their event-related functional magnetic resonance imaging (fMRI) study:
...investigated brain activity elicited by emotional adjectives during silent reading without specific processing instructions. Fifteen healthy volunteers were asked to read a set of randomly presented high-arousing emotional (pleasant and unpleasant) and low-arousing neutral adjectives. Silent reading of emotional in contrast to neutral adjectives evoked enhanced activations in visual, limbic and prefrontal brain regions. In particular, reading pleasant adjectives produced a more robust activation pattern in the left amygdala and the left extrastriate visual cortex than did reading unpleasant or neutral adjectives. Moreover, extrastriate visual cortex and amygdala activity were significantly correlated during reading of pleasant adjectives. Furthermore, pleasant adjectives were better remembered than unpleasant and neutral adjectives in a surprise free recall test conducted after scanning. Thus, visual processing was biased towards pleasant words and involved the amygdala, underscoring recent theoretical views of a general role of the human amygdala in relevance detection for both pleasant and unpleasant stimuli. Results indicate preferential processing of pleasant information in healthy young adults and can be accounted for within the framework of appraisal theory.

Risk-dependent reward value signal in human prefrontal cortex

source: deric bownds

From Tobler et al., observations on brain activity during risk-reward situations that emphasize lateral prefrontal cortex, while the risk-reward study referenced in my April 25 post points at ventral medial prefrontal cortex. It is because of this kind of variation in results reported by different labs that one has to wait a bit for a concensus to emerge on structure-function correlations. Here is the Tobler et al. abstract:
When making choices under uncertainty, people usually consider both the expected value and risk of each option, and choose the one with the higher utility. Expected value increases the expected utility of an option for all individuals. Risk increases the utility of an option for risk-seeking individuals, but decreases it for risk averse individuals. In 2 separate experiments, one involving imperative (no-choice), the other choice situations, we investigated how predicted risk and expected value aggregate into a common reward signal in the human brain. Blood oxygen level dependent responses in lateral regions of the prefrontal cortex increased monotonically with increasing reward value in the absence of risk in both experiments. Risk enhanced these responses in risk-seeking participants, but reduced them in risk-averse participants. The aggregate value and risk responses in lateral prefrontal cortex contrasted with pure value signals independent of risk in the striatum. These results demonstrate an aggregate risk and value signal in the prefrontal cortex that would be compatible with basic assumptions underlying the mean-variance approach to utility.

Psyched out by stereotypes: Research suggests thinking about the positive

In a new study, cognitive scientists have shown that when aware of both a negative and positive stereotype related to performance, women will identify more closely with the positive stereotype, avoiding the harmful impact the negative stereotype unwittingly can have on their performance.

......

more on physorg

Memory grows less efficient very early in Alzheimer's disease

WASHINGTON Even very early in Alzheimer's disease, people become less efficient at separating important from less important information, a new study has found.

Knowing this, clinicians may be able to train people in the early stages of Alzheimer's to remember high-value information better, according to a report in the May issue of Neuropsychology, published by the American Psychological Association.

......

more on biomed.org

Mind and Body Reunite as Premier Indianapolis Psychiatry Practice Adds Integrative Medicine

INDIANAPOLIS, May 4 /PRNewswire/ -- Indiana Health Group (IHG) announced today Angela LaSalle, M.D., Integrative Medicine, will be joining its clinical staff at the Carmel office located at 703 Pro-Med Lane.

For further information about Dr. LaSalle or Indiana Health Group, visit the web sites http://www.indianahealthgroup.net or http://www.angelalasallemd.com.

A graduate of Indiana University School of Medicine, Dr. LaSalle is board certified in Family Medicine with a fellowship in Integrative Medicine through the University of Arizona, a program founded by Andrew Weil, M.D. Hailing from Fort Wayne, IN, Dr. LaSalle's focus has been in the field of Endocrinology, with special emphasis on the interplay of hormones, nutrition and lifestyle on the balance of the neurotransmitters and the immune system. She is the recipient of Fort Wayne Newspaper's 2008 Readers Choice award for Best Physician, and is thrilled that she will be able to broaden her range of services by relocating to Indianapolis.

......

more on biomed.org

Every Cell Is Precious, Every Cell is Great

作者:

The brain's billions of neurons form an incredibly complex network that seems to work in a synchronized manner. Because electrical signals in the organ form larger patterns that are called brain waves, it has been thought that only a large number of cells working together can have an important influence on the rest of the brain's function. Now experiments on the cortex area of mouse brains suggests that even a single cell in the brain can have large implications on the rest of the organ's electrical activity.

From a statement by the Howard Hughes Medical Institute:

Studying anesthetized rats, they used one electrode to spur a neuron to fire rapidly and used another electrode nearby to activate the local neuronal connections. A third electrode was used to pick up the larger pattern emitted by all the neurons in the area. They wanted the overall brain state to remain constant during the experiment, but instead found that tickling one neuron could cause the entire brain state to change.

"Initially, this was very inconvenient," says Dan [Yang Dan]. But then the researchers realized that the phenomenon deserved more attention. Looking more closely, they verified that a neuron firing at high frequency could switch the brain from a “non-REM pattern” of activity to a “REM pattern,” and vice versa.

The result was counterintuitive. “Every neuron makes connections to roughly 1,000 other neurons, but most of those are quite weak,” says Dan. A target cell won’t respond unless many, many neurons that connect to it fire at the same time and therefore she says it’s surprising that a single neuron could change the activity of the whole brain. “Single neurons have more weight than we used to think,” she says.

Dan doesn’t yet know how one cell could exert such power. The researchers had to repeatedly and rapidly fire a cell to cause the pattern to switch, so they might be emulating the effect of many cells firing at once. A neuron doesn’t normally fire in that way, so it is an open question whether the activity of a single neuron could change overall brain pattern under normal circumstances.

Press release: Breaking the Waves: A Single Neuron Can Change the Activity of the Whole Brain ...

Research abstract:
Visual Coding and Cortical Plasticity: From Synapse to Perception

Image: Pyramidal neurons forming a network in the brain. These are nerve cells from the cerebral cortex that have one large apical dendrite and several basal dendrites. Colour-enhanced light microscopy Credit: Dr Jonathan Clarke. Wellcome Images

source: medgadget

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