March 3, 2011

Interactive Video: Progression of Alzheimer’s in the Brain

Click here for an interactive video showing the progression of Alzheimer’s in the brain from the Globe and Mail.

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December 2, 2007

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

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November 1, 2007

Decision-making special issue in Science:

From Mind Hacks: This week’s Science has a special selection of papers on the psychology and neuroscience of decision making. While most of the articles are closed-access, one on how game theory and neuroscience are helping us understand social decision-making is freely available.

It is a great introduction to ‘neuroeconomics’, a field that attempts to work out how the brain supports cost-benefit type decisions.

This can be directly applied to financial decision-making, but also to other types of situations where weighing possible gains and losses is important, whether the gains and losses are in the form of money, time, social advantage or status – to name just a few.

One of the crucial discoveries of recent years is that people do not act as rational maximisers – making individual decisions on how to get the most benefit out of each choice. In fact, social influences can be huge and often lead people to reject no-risk economic gains when then feel it is socially unjustified.

This had led the field into interesting territory, both informing models of the economy, and illuminating how we make social decisions.

As part of the neuroeconomic approach, researchers have begun to investigate the psychological and neural correlates of social decisions using tasks derived from a branch of experimental economics known as Game Theory. These tasks, though beguilingly simple, require sophisticated reasoning about the motivations of other players. Recent research has combined these paradigms with a variety of neuroscientific methods in an effort to gain a more detailed picture of social decision-making. The benefits of this approach are twofold. First, neuroscience can describe important biological constraints on the processes involved, and indeed, research is revealing that many of the processes underlying complex decision-making may overlap with more fundamental brain mechanisms. Second, actual decision behavior in these tasks often does not conform to the predictions of Game Theory, and therefore, more precise characterizations of behavior will be important in adapting these models to better fit how decisions are actually made.

Link to Science special issue on decision making.
Link to article ‘Social Decision-Making: Insights from Game Theory and Neuroscience’.
Link to previous Mind Hacks post on game theory and (ir)rationality.

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October 29, 2007

Young minds — 3 papers

The journal Cognitive Development has released its latest issue, with a few interesting titles.

Among these, we here present three titles with direct impact on the study of consciousness. These cover topics as self-regulation in pre-schoolers, decision making in adolescence, and impulsivity and control in childhood.

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August 26, 2007

Chimps hold out

animal minds,executive functions — thomasr @ 9:20 am

thinkingchimp.jpgResearchers have found that chimps know how to distract themselves with play in order to ward off temptation.

Most children practice this mental trick: When asked to wait patiently for a promised treat–say, an hour of television–they occupy themselves with a toy or a book. Researchers have now shown that chimpanzees engage in similar self-distraction, a finding that further blurs the cognitive and behavioral boundary between humans and other primates. The discovery comes from a study conducted at Georgia State University in Atlanta. Psychologists Theodore Evans and Michael Beran put each of four chimps in front of a container connected to a candy dispenser. The chimps could reach over and pick up the container to eat the accumulated candies at any time, but doing so stopped the dispenser from delivering any more. That allowed the chimps to delay the reward as long as they wanted–so that they could get more of it.

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June 12, 2007

Latest articles on executive functions and will

The scientific study of choice, aka decision making, willed action or executive functions, has provided plenty of new articles just during the past few weeks. Here we provide some of them.

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March 25, 2007

Studying the wandering mind

absent_minded.jpgDo your thoughts stray from your work or studies? Do you catch yourself making to-do lists when your attention should be elsewhere? Welcome to the club.

College students reported mind-wandering almost one-third of the time in their daily lives, according to a new study led by faculty and graduate students at The University of North Carolina at Greensboro. The study will be published in the July issue of Psychological Science.

The study followed 124 undergraduates, who carried personal digital assistants for a week. The PDAs signaled the students eight times a day between noon and midnight to report whether their thoughts were wandering away from what they were doing and to answer multiple-choice questions about their current activity, surroundings and state of mind.

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March 24, 2007

Why We Give In To Temptation

executive functions,self-awareness — thomasr @ 8:18 pm

We’ve all had our moments of weakness when trying to control ourselves; eating that donut on your diet, losing your temper with your kids, becoming upset when you’re doing your best not to. It isn’t like we plan on these lapses in judgment. It’s more like they just sort of happen.

There is scientific evidence that explains this phenomenon of everyday life. Self regulation, our strength to inhibit impulses, make decisions, persist at difficult tasks, and control emotions can be spent just like a muscle that has been lifting heavy weights. When we spend our strength on one task (trying to control your emotion around a petulant boss), there is less to spend on others (avoiding the Ben & Jerry’s when we get home).

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February 8, 2007

How the brain becomes aware of errors

For a long time psychologists have devised methods to make people erroneous on a task. A well-known example is the Stroop effect, a demonstration of interference in the reaction time of a task. When a word such as blue, green, red, etc. is printed in a colour differing from the colour expressed by the word’s semantic meaning (e.g. the word “red” printed in blue ink), a delay occurs in the processing of the word’s colour, leading to slower test reaction times and an increase in mistakes.

The study of the neural correlates of the Stroop effect have revealed, among other correlates, an increased activation in the prefrontal cortex. But what happens if you discover that you have made a mistake and try to correct it? This kind of “error awareness” has now been documented in a recent study published in NeuroImage. We here bring the abstract and a poster.

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