December 18, 2007

Unconscious Perception: Adding a Dorsal Stream to IDA

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December 14, 2007

Personality & Individual Differences — new issue

human nature,journal,personality — thomasr @ 3:28 am

A new issue of the journal Personality and Individual Differences (Volume 44, Issue 3) hosts a number of interesting articles including:

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Cognition & Emotion new issue

A new issue of Cognition & Emotion is out, including articles on emotional memory and awareness, music and emotions, and anger-induction methods.

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December 12, 2007

Call for book reviewers

bookreview,books — thomasr @ 5:49 am

SCR is expanding! We now call for people that are interested in reviewing books. Recently published and forthcoming books are often made available to SCR, and we have the opportunity to bring you the latest news on the consciousness book frontier.

There are two ways to suggest a book review. First, SCR will bring the latest book news as explicit “to be reviewed” headlines. Second, you may have a book you want to review (that has not already appeared at SCR). In both cases, please write to SCR and suggest yourself as a reviewer. If you are interested, please send an email to thomasr AT drcmr DOT dk. Please add some information about yourself; your education, affiliation and interests. Students are encouraged to participate!

We look forward to a continuous expansion of SCR as the forum for the review and discussion of the science of consciousness.

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December 11, 2007

The trivial function of sleep

Rest in poikilothermic animals is an adaptation of the organism to adjust to the geophysical cycles, a doubtless valuable function for all animals. In this review, we argue that the function of sleep could be trivial for mammals and birds because sleep does not provide additional advantages over simple rest. This conclusion can be reached by using the null hypothesis and parsimony arguments.

First, we develop some theoretical and empirical considerations supporting the absence of specific effects after sleep deprivation. Then, we question the adaptive value of sleep traits by using non-coding DNA as a metaphor that shows that the complexity in the design is not a definitive proof of adaptation.

We then propose that few, if any, phenotypic selectable traits do exist in sleep. Instead, the selection of efficient waking has been the major determinant of the most significant aspects in sleep structure. In addition, we suggest that the regulation of sleep is only a mechanism to enforce rest, a state that was challenged after the development of homeothermy.

As a general conclusion, there is no direct answer to the problem of why we sleep; only an explanation of why such a complex set of mechanisms is used to perform what seems to be a simple function. This explanation should be reached by following the evolution of wakefulness rather than that of sleep. Sleep could have additional functions secondarily added to the trivial one, although, in this case, the necessity and sufficiency of these sleep functions should be demonstrated.

The trivial function of sleep. R.V. Rial, Maria C. Nicolau, Antoni Gamundi, Mourad Akaarir, Sara Aparicio, Celia Garau, Silvia Tejada, Catalina Roca, Lluis Gene, David Moranta, Susana Esteban, 2007. Sleep Medicine Reviews 11(4):311-325.

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Belief, disbelief and uncertainty activate distinct brain regions

The capacity of the human mind to believe or disbelieve a statement is a powerful force for controlling both behavior and emotion, but the basis of these states in the brain is not yet understood. A new study found that belief, disbelief and uncertainty activate distinct regions of the brain, with belief/disbelief affecting areas associated with the pleasantness/unpleasantness of tastes and odors. The study will publish online in the Annals of Neurology, the official journal of the American Neurological Association.

Led by Sam Harris of the University of California, Los Angeles, the study involved 14 adults who underwent functional MRI scans during which they were presented with short statements that they had to evaluate as true, false or undecided. Each participant underwent three scans while they evaluated statements from a broad variety of categories such as mathematical, geographical, autobiographical, religious and factual. The statements were designed to be clearly true, false or undecidable.

Contrasting belief and disbelief trials yielded increased signal in the (VMPFC), which is involved in linking factual knowledge with emotion. “The involvement of the VMPFC in belief processing suggests an anatomical link between the purely cognitive aspects of belief and human emotion and reward,” the authors state. The fact that ethical belief showed a similar pattern of activation to mathematical belief suggests that the physiological difference between belief and disbelief is not related to content or emotional associations, they note.

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December 10, 2007

Neurons in the frontal lobe may be responsible for rational decision-making

decision making,human nature,neuroscience — thomasr @ 7:17 am

From physorg.com — You study the menu at a restaurant and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

“Transitivity is the hallmark of rational economic choice,” says Camillo Padoa-Schioppa, a postdoctoral researcher in HMS Professor of Neurobiology John Assad’s lab. According to transitivity, if you prefer A to B and B to C, then you ought to prefer A to C. Or, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

Padoa-Schioppa is lead author on a paper that suggests this trait might be encoded at the level of individual neurons. The study, which appears online Dec. 9 in Nature Neuroscience, shows that some neurons in a part of the brain called the orbitofrontal cortex encode economic value in a “menu invariant” way. That is, the neurons respond the same to steak regardless if it’s offered against salmon or lobster.

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Researchers can read thoughts to decipher what a person is actually seeing

From physorg.com — Following ground-breaking research showing that neurons in the human brain respond in an abstract manner to particular individuals or objects, University of Leicester researchers have now discovered that, from the firing of this type of neuron, they can tell what a person is actually seeing.

The original research by Dr R Quian Quiroga, of the University’s Department of Engineering, showed that one neuron fired to, for instance, Jennifer Aniston, another one to Halle Berry, another one to the Sydney Opera House, etc. The responses were abstract. For example, the neuron firing to Halle Berry responded to several different pictures of her and even to the letters of her name, but not to other people or names.

This result, published in Nature in 2005 and selected as one of the top 100 scientific stories of the year by Discover Magazine, came from data from patients suffering from epilepsy. As candidates for epilepsy surgery, they are implanted with intracranial electrodes to determine as accurately as possible the area where the seizures originate. From that, clinicians can evaluate the potential outcome of curative surgery.

Dr Quian Quiroga’s latest research, which has appeared in the Journal of Neurophysiology, follows on from this. Dr Quian Quiroga explained:

“For example, if the ‘Jennifer Aniston neuron’ increases its firing then we can predict that the subject is seeing Jennifer Aniston. If the ‘Halle Berry neuron’ fires, then we can predict that the subject is seeing Halle Berry, and so on. “To do this, we used and optimised a ‘decoding algorithms’, which is a mathematical method to infer the stimulus from the neuronal firing. We also needed to optimise our recording and data processing tools to record simultaneously from as many neurons as possible. Currently we are able to record simultaneously from up to 100 neurons in the human brain.

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Are Humans Evolving Faster?

From physorg.com –  Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the
National Academy of Sciences:

“We aren’t the same as people even 1,000 or 2,000 years ago,” he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. “The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence.”

“Human races are evolving away from each other,” Harpending says. “Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity.” He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”

“Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups.”

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Subliminal smells bias perception about a person’s likeability

From physorg.com — Anyone who has bonded with a puppy madly sniffing with affection gets an idea of how scents, most not apparent to humans, are critical to a dog’s appreciation of her two-legged friends. Now new research from Northwestern University suggests that humans also pick up infinitesimal scents that affect whether or not we like somebody. “We evaluate people every day and make judgments about who we like or don’t like,” said Wen Li, a post-doctoral fellow in the Cognitive Neurology and Alzheimer’s Disease Center at Northwestern’s Feinberg School of Medicine and lead author of the study. “We may think our judgments are based only on various conscious bits of information, but our senses also may provide subliminal perceptual information that affects our behavior.”

“Subliminal Smells Can Guide Social Preferences” was published in the December issue of Psychological Science. Besides Li, the
study’s co-investigators include Isabel Moallem, Loyola University; Ken Paller, professor of psychology in the Weinberg College of Arts and Sciences at Northwestern; and Jay Gottfried, assistant professor of neurology at Feinberg and senior author of the paper.

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December 7, 2007

How emotions colour our perception of time

emotions,perception — thomasr @ 6:39 am

Our sense of time is altered by our emotions to such an extent that time seems to fly when we are having fun and drags when we are bored. Recent studies using standardized emotional material provide a unique opportunity for understanding the neurocognitive mechanisms that underlie the effects of emotion on timing and time perception in the milliseconds-to-hours range.

We outline how these new findings can be explained within the framework of internal-clock models and describe how emotional arousal and valence interact to produce both increases and decreases in attentional time sharing and clock speed. The study of time and emotion is at a crossroads, and we outline possible examples for future directions

Article by Sylvie Droit-Volet & Warren H. Meck in Trends in Cognitive Sciences, Volume 11, Issue 12, December 2007, Pages 504-513

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December 2, 2007

New issue: Emotion

emotions,journal — thomasr @ 2:42 am

A new issue of Emotion is now out, including articles on audition and time perception, distraction and emotional bias, mood and cognition, and emotioms over time. Here, we bring the table of contents.

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Subjective values

Neuroimaging studies of decision-making have generally related neural activity to objective measures (such as reward magnitude, probability or delay), despite choice preferences being subjective. However, economic theories posit that decision-makers behave as though different options have different subjective values.

Here we use functional magnetic resonance imaging to show that neural activity in several brain regions—particularly the ventral striatum, medial prefrontal cortex and posterior cingulate cortex—tracks the revealed subjective value of delayed monetary rewards.

This similarity provides unambiguous evidence that the subjective value of potential rewards is explicitly represented in the human brain.

Joseph W Kable & Paul W Glimcher, The neural correlates of subjective value during intertemporal choice. Nature Neuroscience 10, 1625 – 1633 (2007)

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November 26, 2007

Social neuroeconomics: the neural circuitry of social preferences

Combining the methods of neuroscience and economics generates powerful tools for studying the brain processes behind human social interaction. We argue that hedonic interpretations of theories of social preferences provide a useful framework that generates interesting predictions and helps interpret brain activations involved in altruistic, fair and trusting behaviors. These behaviors are consistently associated with activation in reward-related brain areas, such as the striatum, and with prefrontal activity implicated in cognitive control, the processing of emotions, and integration of benefits and costs, consistent with resolution of a conflict between self-interest and other-regarding motives.

Fehr & Camerer in Trends in Cognitive Science 2007 Oct ; 11(10): 419-27

Hubmed

PDF of article

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Is Theory of Mind dependent on episodic memory?

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November 22, 2007

Morality starts young

The key to successful social interactions is the ability to assess others’ intentions — be they friend or foe. A new study in 6- and 10-month-old infants shows that humans engage in social evaluations even earlier than was thought, before they can use language. The infants could evaluate actors on the basis of their social acts — they were drawn towards an individual who helps an unrelated third party to achieve his or her goal, and they avoided an individual who hinders a third party’s efforts to achieve a goal. The findings support the claim that precursors to adult-like social evaluation are present even in babies. This skill could be a biological adaptation that may also serve as the foundation for moral thought and action later in life.

Editor summary in Nature

Nature article by Hamlin, Wynn & Bloom

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Consciousness & mind related articles in Psychological Science

human nature,journal — thomasr @ 4:54 pm

Psychological Science is out with a new issue that brings several articles relevant to the SCR audience. Here, we bring some selected abstracts.

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November 20, 2007

Toward a Science of Consciousness: 2008 Conference

calendar-event,conferences — alice @ 12:00 am

The eighth biennial Tucson conference, hosted by the Center for Consciousness Studies and the University of Arizona, continues an interdisciplinary tradition of intense, far-ranging and rigorous discussions on all approaches to the fundamental issue of how the brain produces conscious experience.

The conference will take place from April 8-12, 2008 at the Tucson Convention Center, Tucson, Arizona.

For more information, please check the conference website.

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November 19, 2007

APS 20th Annual Convention

calendar-event,conferences — alice @ 11:29 pm

The Association for Psychological Science (APS) is a nonprofit organization dedicated to the advancement of scientific psychology and its representation.

From May 22-25, 2008, the Sheraton Chicago Hotel & Towers will host thousands of psychological researchers as they converge for presentations by award-winning scientists and leaders across all areas of psychology.

For more information, please check the conference website.

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15th Annual CNS meeting

calendar-event,conferences — alice @ 11:06 pm

This year marks the 15th anniversary of the Cognitive Neuroscience Society (CNS). Founded in 1994, CNS’s mission was to provide its members with a forum to present posters, symposia and to engage in scientific discourse on the understanding of the nature of the mind. 15 years later, CNS’s mission is the same and the Society is going strong thanks to the involvement of its 2,000 members world wide. As usual, the annual meeting promises not to disappoint and it is scheduled to take place from Saturday, April 12 to Tuesday, April 15 at the Hyatt Regency Hotel in San Francisco, California.

For more information, please check the conference website.

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