December 8, 2008

H.M.’s Brain and the History of Memory

memory,web resource — alice @ 2:45 am

For an audio recording provided by the National Public Radio on patient H.M. and his contribution to memory research, click here.

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H. M., an Unforgettable Amnesiac, Dies at 82

memory — alice @ 1:18 am

From The New York Time (4 Dec. 2008): He knew his name. That much he could remember.

He knew that his father’s family came from Thibodaux, La., and his mother was from Ireland, and he knew about the 1929 stock market crash and World War II and life in the 1940s.

But he could remember almost nothing after that.

In 1953, he underwent an experimental brain operation in Hartford to correct a seizure disorder, only to emerge from it fundamentally and irreparably changed. He developed a syndrome neurologists call profound amnesia. He had lost the ability to form new memories.

For the next 55 years, each time he met a friend, each time he ate a meal, each time he walked in the woods, it was as if for the first time.

And for those five decades, he was recognized as the most important patient in the history of brain science. As a participant in hundreds of studies, he helped scientists understand the biology of learning, memory and physical dexterity, as well as the fragile nature of human identity.

On Tuesday evening at 5:05, Henry Gustav Molaison – known worldwide only as H. M., to protect his privacy – died of respiratory failure at a nursing home in Windsor Locks, Conn. His death was confirmed by Suzanne Corkin, a neuroscientist at the Massachusetts Institute of Technology, who had worked closely with him for decades. Henry Molaison was 82.

From the age of 27, when he embarked on a life as an object of intensive study, he lived with his parents, then with a relative and finally in an institution. His amnesia did not damage his intellect or radically change his personality. But he could not hold a job and lived, more so than any mystic, in the moment.

“Say it however you want,” said Dr. Thomas Carew, a neuroscientist at the University of California, Irvine, and president of the Society for Neuroscience. “What H. M. lost, we now know, was a critical part of his identity.”

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Seeking Insights Into the Human Mind in Art and Science

bookreview — alice @ 12:44 am

Proust Was a Neuroscientist
BY JONAH LEHRER
HOUGHTON MIFFLIN, 2007
230 PAGES

Reviewed by Steven Rose, Ph.D.
About Steven Rose, Ph.D.

From The Dana Foundation: Proust was a neuroscientist? No, despite Jonah Lehrer’s provocative title, the novelist Marcel Proust was not.

Proust’s seven-volume novel, À la recherche du temps perdu (English translations are titled either Remembrance of Things Past or In Search of Lost Time), published between 1913 and 1927, is a profound meditation on the nature of emotional and sensual memory and the complex interpersonal relationships of a decadent aristocracy and a rising bourgeoisie. Researchers studying memory will almost certainly be aware of the famous passage, early on in the first volume, where the taste of a madeleine cake evokes in Proust’s semi-autobiographical narrator an entire ensemble of childhood memories, as it is one of the few references to the work of a novelist to find its way regularly into neuroscience textbooks. But while Proust was profoundly introspective and focused on his own thoughts and feelings, his concern with the bodily mechanisms that underlay them was almost certainly confined to medical consultations about his perennially poor health.

Lehrer’s title thus reflects both the ambitious goals of his book and their limitations. His thesis, presented in a series of eight case studies, is that through the 19th and early 20th centuries, writers, painters, musicians, and even cooks achieved insights into the mind that both contradicted the assumptions of the sciences of their time and anticipated some of the understanding of the brain that modern neuroscience offers. It’s a fun and thought-provoking argument, even though I feel that at times his case remains at best non-proven.

Click here for complete article.

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November 24, 2008

Real-time chemical responses in the nucleus accumbens differentiate rewarding and aversive stimuli

neurochemistry,neuroscience,perception — alice @ 1:28 am

Mitchell F Roitman, Robert A Wheeler, R Mark Wightman and Regina M Carelli
Article in Nature Neuroscience

Abstract
Rewarding and aversive stimuli evoke very different patterns of behavior and are rapidly discriminated. Here taste stimuli of opposite hedonic valence evoked opposite patterns of dopamine and metabolic activity within milliseconds in the nucleus accumbens. This rapid encoding may serve to guide ongoing behavioral responses and promote plastic changes in underlying circuitry.

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Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model

Christoph Börgers, Steven Epstein, and Nancy J. Kopell
Article in Proceedings of the National Academy of Science, USA

Abstract
Simultaneous presentation of multiple stimuli can reduce the firing rates of neurons in extrastriate visual cortex below the rate elicited by a single preferred stimulus. We describe computational results suggesting how this remarkable effect may arise from strong excitatory drive to a substantial local population of fast-spiking inhibitory interneurons, which can lead to a loss of coherence in that population and thereby raise the effectiveness of inhibition. We propose that in attentional states fast-spiking interneurons may be subject to a bath of inhibition resulting from cholinergic activation of a second class of inhibitory interneurons, restoring conditions needed for gamma rhythmicity. Oscillations and coherence are emergent features, not assumptions, in our model. The gamma oscillations in turn support stimulus competition. The mechanism is a form of “oscillatory selection,” in which neural interactions change phase relationships that regulate firing rates, and attention shapes those neural interactions.

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The Decider

Informing the debate over the reality of ‘free will’ requires learning something about the lateral habenula.

From ScienceNews: At the end of The Matrix trilogy, Neo and Agent Smith are engaged in one final, interminable scene of surreal combat, a surrogate competition for an eternal battle between humans and machines. “It’s pointless to keep fighting,” Agent Smith declares to Neo. “Why do you persist?”

“Because I choose to,” Neo replies, just before the computer-generated Smith meets his demise in a cinematic celebration of human free will’s superiority to the programming that enslaves machines. Machines are mindless. The brain is a decider.

All very inspiring, except that the brain itself is a machine, a network of cells that computes its choices based on the sum of sensory inputs and their interactions with neural anatomy. “Free will” is not the defining feature of humanness, modern neuroscience implies, but is rather an illusion that endures only because biochemical complexity conceals the mechanisms of decision making.

Yet belief in free will persists as stubbornly as Neo’s resistance to electronic tyranny. Whether supposedly free choice is actually a Matrix-like mirage remains one of the great questions of human philosophical history. For centuries that question was assessed mostly with thought -uninformed by actual neurobiological knowledge. Nowadays, though, the inner workings of the brain are revealing themselves to modern methods of neuroinquiry, and free will seems merely to emerge from electrochemical networks of neuronal interactions. But like tourists exploring a strange city without a GPS map, scientists don’t know how all the neural neighborhoods are connected and occasionally encounter surprising enclaves-such as a place in the brain called the lateral habenula.

“There’s lots of new research showing that an overactive habenula has behavioral effects,” says neuropharmacologist Martine Mirrione of Brookhaven National Laboratory in Upton, N.Y.

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November 20, 2008

“Giving Up Maleness”: Abraham Maslow, Masculinity, and the Boundaries of Psychology

history — alice @ 1:37 am

In a paper in History of Psychology, Nicholson (2001) examines Abraham Maslow’s attempt to reconstruct the boundaries of psychology. This paper focuses on Maslow’s struggle to find a way to “soften” scientific psychology without completely undermining what he believed was its essentially male nature.  Nicholson argues that Maslow’s attempt to broaden what it meant to be a psychologist was intimately linked to the question of what it meant to be a man, and that Maslow’s struggle to come to terms with his masculinity should stand as a testament to the power of gender assumptions in psychology and in American professional life as a whole.  According to Nicholson, Maslow stands as a dramatic demonstration of how significant the search for a powerful masculinity can be for the seemingly unrelated task of developing a powerful discipline.

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November 17, 2008

BOOK: Frontiers of consciousness — The Chichele lectures

books,reviews,theory — thomasr @ 10:31 am

Frontiers of ConsciousnessIn recent years consciousness has become a significant area of study in the cognitive sciences. The ‘Frontiers of Consciousness‘ is a major interdisciplinary exploration of consciousness. The book stems from the Chichele lectures held at All Souls College in Oxford, and features contributions from a ‘who’s who’ of authorities from both philosophy and psychology. The result is a truly interdisciplinary volume, which tackles some of the biggest and most impenetrable problems in consciousness.

The book includes chapters considering the apparent explanatory gap between science and consciousness, our conscious experience of emotions such as fear, and of willed actions by ourselves and others. It looks at subjective differences between two ways in which visual information guides behaviour, and scientific investigation of consciousness in non-human animals. It looks at the challenges that the mind-brain relation presents for clinical practice as well as for theories of consciousness. The book draws on leading research from philosophy, experimental psychology, functional imaging of the brain, neuropsychology, neuroscience, and clinical neurology.

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November 9, 2008

Self-awareness deficits following loss of inner speech: Dr. Jill Bolte Taylor’s case study

personal identity,self-awareness — alice @ 5:08 am

Alain Morin
Article in Consciousness and Cognition

Abstract
In her 2006 book ‘‘My Stroke of Insight” Dr. Jill Bolte Taylor relates her experience of suffering from a left hemispheric stroke caused by a congenital arteriovenous malformation which led to a loss of inner speech. Her phenomenological account strongly suggests that this impairment produced a global self-awareness deficit as well as more specific dysfunctions related to corporeal awareness, sense of individuality, retrieval of autobiographical memories, and self-conscious emotions. These are examined in details and corroborated by numerous excerpts from Taylor’s book.

Click here for complete article.

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November 5, 2008

How good are you at Self-Control?

SCR Feature — alice @ 1:47 am

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Connectomics: Tracing the Wires of the Brain

brain networks — alice @ 12:54 am

From The Dana FoundationScientists working with rapidly advancing computer technology and electron microscopes hope one day to map the billions of neuronal connections in the brain. The resulting map, or “connectome,” could help us understand memory, intelligence and mental disorders, Dr. Sebastian Seung writes.

Suppose that someone gave you a radio and asked you to figure out how it works. You could try measuring electrical signals inside it, but the measurements might not be sufficient. You might be more successful if you were also given a circuit diagram illustrating all the components of the radio and how they are connected to each other.

Now imagine that your goal is to discover how a brain works. A map of brain connections would be helpful for interpreting measurements of the signals transmitted between neurons. In the human brain, these signals travel in a complex network of 100 billion or so neurons, each of which is connected to 10,000 others.

Such a map of a brain, human or otherwise, does not yet exist. But as technology advances, researchers are setting their sights on the “connectome,” a word coined in a 2005 study by Olaf Sporns and colleagues to describe a complete map of connections in a brain or a piece of a brain.

Click here for complete article.

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November 3, 2008

Human Brain is Capable of Subliminal Conditioning, Study Shows

From The Dana Foundation: Imagine you are playing a game of poker. Watching your opponent, you have a gut feeling that if you raise the bet, he will fold. You decide to go with your intuition and it works.

Were you just lucky?

According to neuroscientist Mathias Pessiglione, the gut feeling you experienced could be the result of your brain picking up subliminal cues from your opponent and associating them with a positive outcome. Pessiglione uses a poker game as a possible real-life example of the kind of subliminal instrumental conditioning that he and his colleagues at the Institut National de la santé et de la recherche médicale (INSERM), a public research institute in Paris, have demonstrated for the first time in the human brain.

They report the results of a carefully designed study using a system of masked cues matched to win or loss outcomes in the Aug. 28 issue of the journal Neuron.

Click here for complete article.

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November 2, 2008

Art Teams With Science to Explain It All to You

attention,perception — alice @ 11:53 pm

From NY Times (Oct 31, 2008):  The taste of a ripe tomato, the hook of a catchy song, the scent of a lover’s hair. What is it, exactly, that drives us to seek these things again and again?

Neuroscientists who study perception are starting to discover the inner workings of the sensory mind. Starting on Monday at the New York Academy of Sciences, researchers and artists will team up to explore this new research in a series of talks called Science of the Five Senses. Their conversations will raise a question for the amateur hedonist: If we had a better understanding of the signals our bodies send to our brains, might we take more pleasure from them? 

Click here for complete article.

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Online papers on consciousness

web resource — alice @ 11:52 pm

David Chalmers had compiled a directory of 2573 online papers on consciousness and related topics. Most of these papers are by academic philosophers or scientists. Click here to check out this great online resource.

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Theta phase synchrony and conscious target perception: Impact of intensive mental training

Heleen A. Slagter, Antoine Lutz, Lawrence L. Greischar, Sander Nieuwenhuis, and Richard J. Davidson.
Article in Journal of Cognitive Neuroscience

Abstract
The information processing capacity of the human mind is limited, as is evidenced by the attentional blink-a deficit in identifying the second of two targets (T1 and T2) presented in close succession. This deficit is thought to result from an overinvestment of limited resources in T1 processing. We previously reported that intensive mental training in a style of meditation aimed at reducing elaborate object processing, reduced brain resource allocation to T1, and improved T2 accuracy [Slagter, H. A., Lutz, A., Greisschar, L. L., Frances, A. D., Nieuwenhuis, S., Davis, J., et al. Mental training affects distribution of limited brain resources. PloS Biology, 5, e138, 2007]. Here we report EEG spectral analyses to examine the possibility that this reduction in elaborate T1 processing rendered the system more available to process new target information, as indexed by T2-locked phase variability. Intensive mental training was associated with decreased cross-trial variability in the phase of oscillatory theta activity after successfully detected T2s, in particular, for those individuals who showed the greatest reduction in brain resource allocation to T1. These data implicate theta phase locking in conscious target perception, and suggest that after mental training the cognitive system is more rapidly available to process new target information. Mental training was not associated with changes in the amplitude of T2-induced responses or oscillatory activity before task onset. In combination, these findings illustrate the usefulness of systematic mental training in the study of the human mind by revealing the neural mechanisms that enable the brain to successfully represent target information.

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The Problem of Consciousness

essays,web resource — alice @ 12:26 am

John R. Searle 
Copyright John R. Searle. Click here for complete online text.

The most important scientific discovery of the present era will come when someone — or some group — discovers the answer to the following question: How exactly do neurobiological processes in the brain cause consciousness? This is the most important question facing us in the biological sciences, yet it is frequently evaded, and frequently misunderstood when not evaded. In order to clear the way for an understanding of this problem. I am going to begin to answer four questions: 1. What is consciousness? 2. What is the relation of consciousness to the brain? 3. What are some of the features that an empirical theory of consciousness should try to explain? 4. What are some common mistakes to avoid?

* An earlier version of this article has appeared in the publications of the CIBA Foundation. The theses advanced in this paper are presented in more detail and with more supporting argument in Searle, J.R. The Rediscovery of the Mind, MIT Press, 1992.

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October 31, 2008

Is surfing the internet altering your brain?

From Reuters: CANBERRA (Reuters) – The Internet is not just changing the way people live but altering the way our brains work with a neuroscientist arguing this is an evolutionary change which will put the tech-savvy at the top of the new social order.

Gary Small, a neuroscientist at UCLA in California who specializes in brain function, has found through studies that Internet searching and text messaging has made brains more adept at filtering information and making snap decisions.

But while technology can accelerate learning and boost creativity it can have drawbacks as it can create Internet addicts whose only friends are virtual and has sparked a dramatic rise in Attention Deficit Disorder diagnoses.

Small, however, argues that the people who will come out on top in the next generation will be those with a mixture of technological and social skills.

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October 26, 2008

New vistas for alpha-frequency band oscillations

EEG,attention,brain networks,memory — alice @ 3:50 am

Palva S, Palva JM.
Article in Trends in Neurosciences

Abstract
The amplitude of alpha-frequency band (8-14 Hz) activity in the human electroencephalogram is suppressed by eye opening, visual stimuli and visual scanning, whereas it is enhanced during internal tasks, such as mental calculation and working memory. Alpha-frequency band oscillations have hence been thought to reflect idling or inhibition of task-irrelevant cortical areas. However, recent data on alpha-amplitude and, in particular, alpha-phase dynamics posit a direct and active role for alpha-frequency band rhythmicity in the mechanisms of attention and consciousness. We propose that simultaneous alpha-, beta- (14-30 Hz) and gamma- (30-70 Hz) frequency band oscillations are required for unified cognitive operations, and hypothesize that cross-frequency phase synchrony between alpha, beta and gamma oscillations coordinates the selection and maintenance of neuronal object representations during working memory, perception and consciousness.

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I move, therefore I am: A new theoretical framework to investigate agency and ownership

personal identity,self-awareness — alice @ 1:12 am

Matthis Synofzik, Gottfried Vosgerau and Albert Newen
Article in Consciousness and Cognition

Abstract
The neurocognitive structure of the acting self has recently been widely studied, yet is still perplexing and remains an often confounded issue in cognitive neuroscience, psychopathology and philosophy. We provide a new systematic account of two of its main features, the sense of agency and the sense of ownership, demonstrating that although both features appear as phenomenally uniform, they each in fact are complex crossmodal phenomena of largely heterogeneous functional and (self-)representational levels. These levels can be arranged within a gradually evolving, onto- and phylogenetically plausible framework which proceeds from basic non-conceptual sensorimotor processes to more complex conceptual and meta-representational processes of agency and ownership, respectively. In particular, three fundamental levels of agency and ownership processing have to be distinguished: The level of feeling, thinking and social interaction. This naturalistic account will not only allow to “ground the self in action”, but also provide an empirically testable taxonomy for cognitive neuroscience and a new tool for disentangling agency and ownership disturbances in psychopathology (e.g. alien hand, anarchic hand, anosognosia for one’s own hemiparesis).

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Attention regulation and monitoring in meditation

attention,emotions,meditation,reviews — alice @ 12:41 am

Antoine Lutz, Heleen A. Slagter, John D. Dunne and Richard J. Davidson
Review article in Trends in Cognitive Sciences, click here for full article

Abstract:
Meditation can be conceptualized as a family of complex emotional and attentional regulatory training regimes developed for various ends, including the cultivation of well-being and emotional balance. Among these various practices, there are two styles that are commonly studied. One style, focused attention meditation, entails the voluntary focusing of attention on a chosen object. The other style, open monitoring meditation, involves nonreactive monitoring of the content of experience from moment to moment. The potential regulatory functions of these practices on attention and emotion processes could have a long-term impact on the brain and behavior.

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