Decision, Decisions

A recent Science Magazine issue has a special section on the underlying processes of decision-making. Here is Peter Stern's introduction to the section:

Who hasn't agonized over a major decision in life, whether to accept a job offer, move house, or perhaps switch research fields? We are confronted with a multitude of decisions on a daily basis. Many decisions are trivial and can be dealt with in seconds. However, others may have wider ramifications and can be excruciatingly complicated. In the past few years, our understanding of the underlying processes of decision-making has progressed markedly. This neuroscience special issue highlights some of the most exciting developments in this area.

Koechlin and Hyafil review recent experimental studies that provide new insights into the function and connectivity of the anterior prefrontal cortex, which forms the apex of the executive system underlying decision-making. The authors propose an original model of the anterior prefrontal function and provide a theoretical framework for addressing major unresolved issues and guiding future research on decision-making and higher cognition.

Human beings are highly social animals. Many of our decisions make sense only within a social environment. Sanfey outlines the advantages that can be gained by combining tasks and formal mathematical models from game theory with modern neuroimaging methods to characterize the processes that underlie social decision-making. He also summarizes recent research that offers good examples of how this neuroeconomic approach has already begun to illuminate our knowledge of this process.

Sometimes things can also go wrong in this complicated and well-balanced interplay between several brain regions. Paulus proposes that decision-making in psychiatric populations cannot be viewed simply as an alteration of the preference structure or the way individuals experience the outcome of the decision. Instead, it must be understood from the homeostatic balance perspective of the individual. Increased risk-taking behavior in drug addicts, for example, although maladaptive in the generic sense, may actually be adaptive for the substance user in a complex, highly unpredictable environment while attempting to respond to internal urges and cravings.

Decision theory has boomed in the past decade. Körding gives an overview of how decision theory, including normative/Bayesian approaches, can lead us to better understand the functions of the nervous system.

Mozart vs. James Bond

This is a hoot, if you are in for a moment of comic relief.

A Ramachandran lecture...

In this excellent and engaging talk, Vilayanur Ramachandran discusses how brain damage can reveal the connection between internal structures of the brain and corresponding functions of the mind. Focus is on phantom limb pain, synesthesia (when people hear color or smell sounds), and the Capgras delusion (when brain-damaged people believe their closest friends and family have been replaced with imposters.)

Thinking like a genius

Here is a stimulating stumble.

MindBlog on the road

Congress Avenue, Austin Texas
I drove from Madison, WI to Austin, Texas this past weekend, to visit my son and his wife. They now live in the family house I where I grew up. Tomorrow I hit the road again to drive to Ft. Lauderdale, MindBlog's winter home. The timing turns out to have been perfect, it is 24 degrees fahrenheit with light snow flurries in Madison right now .

Blog postings might be a bit flakey this week.

Drug craving? - Just zap your insula!

An important factor that contributes to drug-seeking in addicted individuals is the negative feelings that result from abstinence. Such mood states are monitored by the interoceptive sensory system, and particularly by a brain area called the insular cortex, known to process emotional information. Thus this abstract from Contreras et al. is of interest:

Addiction profoundly alters motivational circuits so that drugs become powerful reinforcers of behavior. The interoceptive system continuously updates homeostatic and emotional information that are important elements in motivational decisions. We tested the idea that interoceptive information is essential in drug craving and in the behavioral signs of malaise. We inactivated the primary interoceptive cortex in amphetamine-experienced rats, which prevented the urge to seek amphetamine in a place preference task. Interoceptive insula inactivation also blunted the signs of malaise induced by acute lithium administration. Drug-seeking and malaise both induced Fos expression, a marker of neuronal activation, in the insula. We conclude that the insular cortex is a key structure in the perception of bodily needs that provides direction to motivated behaviors.

The therapeutic intervention was an injection of 2% lidocaine (a sodium channel blocker to inhibit nerve activity) into the left and right insula to cause a transient shutdown of insular nerve activity (injecting adjacent cortex was not effective). Although this is a sledgehammer approach with possible dire side effects, it suggests that therapeutic interventions in the insula may help to alleviate drug cravings, .

Music and Dancing

Daniel Levitin has offered this brief essay in the New York Times Op-Ed section.

Less SAD with more sun and serotonin

Welberg offers a summary and review of work by Willeit et al. on the role of serotonin, and a serotonin transporter, in seasonal affective disorder. Here is an portion of the review:

Short, dark winter days put most of us in a gloomy mood, but in people with seasonal affective disorder (SAD), they can cause severe clinical depression. Fortunately, this depression can be treated with bright-light therapy (BLT), and it disappears altogether in summer. Willeit et al. now show that these changes in mood are associated with alterations in the efficiency of the serotonin (5-hydroxytryptamine) transporter (5-HTT) in the patients' blood platelets.

One theory of depression posits that impaired functioning of monoamine neurotransmitters, such as serotonin, causes the disorder, but it is unknown how this impairment might arise. Serotonin levels in the synapse are controlled by the 5-HTT, and Willeit and colleagues therefore investigated whether alterations in 5-HTT functioning might underlie depression in SAD.

The authors compared people with SAD with healthy volunteers, and assessed 5-HTT functioning in winter, after 4 weeks of BLT and in summer. They did this by measuring 5-HTT-mediated inward and outward transport in blood platelets (which are easily obtainable). In winter, both inward transport rate and outward transport were enhanced in the platelets of SAD patients compared with healthy controls. Importantly, these differences in platelet 5-HTT functioning disappeared after 4 weeks of BLT and were absent in summer. The number of 5-HTTs and their affinity for serotonin did not change with BLT or with the seasons, indicating that the increased 5-HTT inward transport that was found in SAD patients was due to increased efficiency of the transporter.

The authors also assessed the patients' depression levels at the three time points, using a structured interview. They found that post-treatment, both inward transport rate and outward transport correlated with depression scores in SAD patients. Moreover, patients whose depression did not decrease after treatment did not show a change in 5-HTT-mediated outward transport after treatment.

Are we having fun?

This is an engaging bit of fluff, be happy! (if the Strauss waltz repeated in a loop doesn't drive you crazy.)

Short-term meditation training improves attention and self-regulation

An interesting study from Tang et al. showing that even short term meditation training can influence attention and self-regulation. The integrative meditation method used:

...stresses no effort to control thoughts, but instead a state of restful alertness that allows a high degree of awareness of body, breathing, and external instructions from a compact disc. It stresses a balanced state of relaxation while focusing attention. Thought control is achieved gradually through posture and relaxation, body–mind harmony, and balance with the help of the coach rather than by making the trainee attempt an internal struggle to control thoughts in accordance with instruction.

Their abstract:

Recent studies suggest that months to years of intensive and systematic meditation training can improve attention. However, the lengthy training required has made it difficult to use random assignment of participants to conditions to confirm these findings. This article shows that a group randomly assigned to 5 days of meditation practice with the integrative body–mind training method shows significantly better attention and control of stress than a similarly chosen control group given relaxation training. The training method comes from traditional Chinese medicine and incorporates aspects of other meditation and mindfulness training. Compared with the control group, the experimental group of 40 undergraduate Chinese students given 5 days of 20-min integrative training showed greater improvement in conflict scores on the Attention Network Test, lower anxiety, depression, anger, and fatigue, and higher vigor on the Profile of Mood States scale, a significant decrease in stress-related cortisol, and an increase in immunoreactivity. These results provide a convenient method for studying the influence of meditation training by using experimental and control methods similar to those used to test drugs or other interventions.

Another window into the minds of chimps and humans

Rilling et al. compare resting-state brain activity in humans and chimpanzees:

In humans, the wakeful resting condition is characterized by a default mode of brain function involving high levels of activity within a functionally connected network of brain regions. This network has recently been implicated in mental self-projection into the past, the future, or another individual's perspective. Here we use [18F]-fluorodeoxyglucose positron emission tomography imaging to assess resting-state brain activity in our closest living relative, the chimpanzee, as a potential window onto their mental world and compare these results with those of a human sample. We find that, like humans, chimpanzees show high levels of activity within default mode areas, including medial prefrontal and medial parietal cortex. Chimpanzees differ from our human sample in showing higher levels of activity in ventromedial prefrontal cortex and lower levels of activity in left-sided cortical areas involved in language and conceptual processing in humans. Our results raise the possibility that the resting state of chimpanzees involves emotionally laden episodic memory retrieval and some level of mental self-projection, albeit in the absence of language and conceptual processing.

Our Brains on Music, and Musicophilia

Steven Pinker has called music useless, with no adaptive value. Oliver Sacks and Daniel Levitin beg to differ. I'm currently reading and enjoying Oliver Sacks' new book: Musicophilia: Tales of Music and the Brain. I'm linking you to a review of this book by Laura Garwin in the current issue of Nature that notes that our brains seem to be finely tuned to music, and asks of what use are our musical powers and passions? She also reviews Levitin's "This is Your Brain on Music: Understanding a Human Obsession." I also thoroughly enjoyed reading this book this past spring, it has a very accessible introduction of the fundamentals of music structure and brain mechanisms associated with music processing.

The hash realities

Murray et al. offer an interesting history and analysis of Cannabis use, with several interesting graphics (PDF here):

Cannabis has been known for at least 4,000 years to have profound effects on the mind — effects that have provoked dramatically divergent attitudes towards it. Some societies have regarded cannabis as a sacred boon for mankind that offers respite from the tribulations of everyday life, whereas others have demonized it as inevitably leading to 'reefer madness'. The debate between the protagonists and prohibitionists has recently been re-ignited, but unfortunately this debate continues mainly in ignorance of our new understanding of the effects of cannabis on the brain and of studies that have quantified the extent of the risks of long-term use.

A Consciousness Debate

Christof Koch and Susan Greenfield offer a written version of their Oxford University Debate in the summer of 2006 in the Oct. 2007 issue of Scientific American. While they make a point of contrasting their models of the neuronal correlates of consciousness, I think a blending of the two may most closely approach the real situation.

What happens in your brain when you see a dog, hear a voice, suddenly feel sad or have any other subjective experience?

KOCH'S MODEL
A coalition of pyramidal neurons linking the back and front of the cortex fires in a unique way. Different coalitions activate to represent different stimuli from the senses (left). In a mouse cortex (right) these pyramidal cells (green) lie in brain layer 5, surrounded by nonneuronal cells (blue).


GREENFIELD'S MODEL
Neurons across the brain fire in synchrony (green) and prevail until a second stimulus prompts a different assembly to arise (orange). Various assemblies coalesce and disband moment to moment, while incorporating feedback from the body. In a rat brain (bottom), an assembly in the cortex forms (a, b), peaks (c), then decays (d) within 0.35 second after the thalamus is electrically stimulated.

Christof Koch is professor of cognitive and behavioral biology at the California Institute of Technology, where he teaches and has conducted research on the neuronal basis of visual attention and consciousness for more than two decades.

Susan Greenfield is professor of pharmacology at the University of Oxford, director of the Royal Institution of Great Britain and member of the British Parliament's House of Lords. Her research focuses on novel brain mechanisms, including those underlying neurodegenerative diseases.

A new consiousness and philosophy of mind bibliography

David Chalmers and David Bourget are offering a more extensive online service, outlined in this message from ASSC (Assoc. for Sci.Stud. Cons.):

We are pleased to announce the launch of MindPapers, a new website
with a bibliography covering around 18000 published papers and online
papers in the philosophy of mind and the science of consciousness.
This site grew out of a combination of David Chalmers' bibliography in
philosophy of mind and his page of online papers on consciousness, but
it is much larger and has many new capacities, programmed by David
Bourget. The site address is:

http://consc.net/mindpapers/

There is also a separate front end for "Online Papers on
Consciousness". Where MindPapers now combines both offline published
papers and online papers from free and commercial sites, Online Papers
on Consciousness is devoted to free online papers (currently around
4700). It is based on the same database as MindPapers, but is
organized in a way to emphasize issues concerning consciousness and
cognitive science rather than the philosophy of mind. The address is

http://consc.net/online/

The MindPapers database contains 2773 papers on the philosophy of
consciousness (under 59 topics and subtopics) and 3917 papers on the
science of consciousness (under 71 topics and subtopics), as well as
thousands of papers on such related topics as perception,
intentionality, the philosophy of AI, and the philosophy of cognitive
science.

Capacities include (i) links and citation information throughout, (ii)
flexible navigation, display, and search options, (iii) the ability to
submit and edit entries, (iv) the capacity for automated off-campus
proxy access to commercial sites, and (v) a wealth of statistical
information.

We encourage everyone to try these sites to submit any relevant
material that we are missing (for a start, try searching on your own
name). There are tools on the site for submitting entries, as well as
for correcting entries and notifying us of any bugs and suggestions.

--David Chalmers and David Bourget
chalmers@anu.edu.au; david.bourget@anu.edu.au

Sleep deprivation diminishes recall of neutral and positive, but not of negative, events.

We remember emotional events, particularly negative ones, better than neutral events. Sterpenich et al. show that while consolidation of neutral and posititive memories is diminished by sleep deprivation, recall of negative events is less compromised. They show that after sleep deprivation, recollection of negative, potentially dangerous, memories recruits an alternate amygdalo-cortical network, which would keep track of emotional information despite sleep deprivation. Here is their description of the work:

Declarative memories, which can be consciously and verbally retrieved, are initially critically dependent on the hippocampus. However, reliable retrieval of long-term memory depends on a process of consolidation, which partly occurs during sleep, when memories are thought to be progressively transferred to long-term cortical stores. Because people tend to remember emotional memories better than neutral ones, we wondered whether the emotional significance of a memory would enhance its consolidation in a sleep-dependent manner. During a first session, participants viewed pictures with neutral and emotional content without realizing that their memory of the pictures and their content would be tested later (called incidental encoding). Three days later, during a functional MRI scanning session, subjects indicated whether they recognized previously viewed and new pictures. Half of the subjects were totally sleep deprived during the first post-encoding night, but all subjects slept as usual during the second and third post-encoding nights. We show here that the recollection of emotional stimuli elicited larger responses in the hippocampus and various cortical areas in the well-rested group than in the sleep-deprived group, suggesting that emotional significance boosts memory consolidation of the information during sleep. Interestingly, in sleep-deprived subjects, recollection of negative items recruited another network including the amygdala, as if an alternate consolidation process allowed them to keep track of negative, potentially dangerous, information despite the cognitive aftermath of sleep deprivation.

Biology and Health Inequality

PLoS Biology has ventured beyond its usual fare to publish several articles focusing on poverty, human development, and the environment. This article is from Eric Brunner. He points out several studies that demonstrate a direct psychosocial pathway to disease. It's precis: "Intriguing parallels between civil servant and nonhuman primate hierarchies suggest that highly stratified societies foster health inequalities. Determining how social differences translate into chronic disease remains a challenge, but neuroendocrine pathways appear to play a role."

Silent Minds

I want to point you to an excellent article by Jerome Groopman, with the title of this post, that appeared in a recent New Yorker Magazine. It describes recent work showing that brain imaging of some vegetative patients reveals responses to faces, and other visual and auditory inputs, that are indistinguishable from those of normal subjects (note: there are approximately 35,000 Americans in a vegetative state and another 280,000 in a minimally conscious state). Responses during various mental tasks, such as resolving ambiguous sentences or imagining playing a tennis game, can also be normal. This shows that an assumption held by doctors for decades - that vegetative patients lack capacity for conscious thought - is incorrect. Other vegetative patients (such as Terri Schiavo), in contrast, can show almost no cortical activity.

This all suggests a better medical definition of consciousness is required - such as the ability to report to ourselves or others the content of the representations in our brains, to sustain these representations over time and broadcast them broadly within the brain.

Evolution - with feeling....

A recent issue of American Scientist has a review by Robert Pennock of two books that attempt to show that a mechanistic Darwinian view of the world does not have to lead to a nihilistic ennui, but rather can satisfy our need to feel richness, purpose, and meaning.

With the familiar references to the "uncaring" Darwinian struggle, and the "mechanical" and "pitiless" action of natural selection, evolutionary biology has long been the obvious whipping boy for those who are uncomfortable with scientific naturalism. It is not just fundamentalist religious beliefs that motivate creationists' attacks on evolution; they are also driven by a deep existential angst—a fear that evolution renders the world pointless, emptying it of purpose, meaning and morality.

In "Darwin Loves You:Natural Selection and the Re-enchantment of the World" George Levine argues that evolution

if properly portrayed, is not only perfectly compatible with meaningfulness but provides a new basis for it...He makes the important point that at the same time that evolution pulls the rug out from under anthropocentrism (which is not only a smug but ultimately a dangerous attitude), it provides a foundation for a justifiable form of anthropomorphism. Darwin showed that humans are not the apex of creation but are one with the rest of the biological world, related to all living things through our common ancestors. This discovery allows us to find common ground with other animals without denigrating our humanness, Levine argues, permitting us to legitimately attribute human characteristics (albeit in simpler or incipient forms) to them. This provides an avenue to the re-enchantment of the world, for it shows we are not wrong to find in it a recognizably human notion of meaningfulness. It is wrong to see nature as cold and unfeeling; for those who understand evolutionary processes and relationships, the biological world becomes a warm and caring network of mutual interactions that are suffused with meaning. Levine is a romantic, but not a naive one; he does not close his eyes to those aspects of nature that are "red in tooth and claw," but shows how these need not negate the positive vision.

In "Evolution for Everyone: How Darwin's Theory Can Change the Way We Think about Our Lives" David Sloan Wilson, in the service of finding harmony between evolution and religion:

...discusses some of the evidence for his evolutionary hypothesis that religions are adaptive at the group level, providing practical benefits relating to the specific conditions the group is confronted with...Given the central importance of evolution in biology, the most extraordinary thing about the public's view, Wilson points out, is not that 50 percent don't believe it, but that nearly 100 percent haven't connected it to anything of importance in their lives. One of Wilson's chief goals—one he accomplishes admirably—is to demonstrate the relevance and value of evolutionary biology not just to scientists but to ordinary people. In story after engaging story, he conveys not only the sweep and the power of evolutionary thinking but the grandeur, as Darwin put it, of this view of life. By the end of the book, the reader understands Wilson's metaphor that evolution is an artist that has helped fashion the sculpture that is the living world.

The Outsourced Brain

I can't resist passing on this clever NY Times Op-Ed piece by David Brooks - on the subject of the dissolution of our individual intelligences into the mush of the infosphere.