February 24, 2011

Meditation alters your grey matter, studies show

From the Globe and Mail:

Move over cryptic crosswords and Sudoku, and make way for the ultimate mental workout. It’s called Mindfulness-Based Stress Reduction, or MBSR for short. Recent neuroscience research shows that novices using the method – developed at the University of Massachusetts Medical School in the 1970s – can get results in just eight weeks.

Brain-changing results, that is.

A 2010 study found that non-meditators who had eight weeks of MBSR training were more likely than a control group to access the brain region that provides a bodily sense of the “here and now” as opposed to the region associated with worry.

In other research published in January, brain scans of MBSR participants with no previous meditation experience showed increased grey-matter density in regions involved in learning and memory, emotion regulation, self-awareness and perspective taking.

Click here to read the rest of the article.

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December 7, 2010

The Same Old Consciousness

From: ErvinLaszlo.com:  It makes sense to paraphrase Einstein’s famous dictum in regard to consciousness. Our problem is the unsustainability of the world we have created, and we should be clear that we can’t solve this problem with the same kind of consciousness that gave rise to it.

But many people try to do just that, even the leaders of the world’s twenty richest and most powerful nations. The November 2010 meeting of the G20 in Seoul gave indisputable proof of it. Not only did the meeting fail to achieve its main objectives (among them rebalancing international trade and reaching an accommodation between the U.S. and South Korea), the objectives themselves proved to be out-of-date. They centered on re-stabilizing the same moribund economic and financial system that made the world unsustainable in the first place.

But why is the G20’s failure due to wrong consciousness? Because consciousness in the social, political, and cultural context is sum total of our view of the world, with its values, aspirations, and background assumptions. It’s the “paradigm” that underlies the way we think and the way we set our priorities. The consciousness of the G20 gives rise to an obsolete view of the world, with faulty values and outdated aspirations. The leaders view the world as the arena for a Darwinian struggle for survival, seen as a competition for growth in the economies of nations. Since assured growth cannot be achieved even by the wealthiest and most powerful nation in the world by itself, the leaders recognize the need for some level and form of cooperation—as a means to an end. The end is for the rich nations to make sure that they remain rich.

Click here for the complete article.

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November 15, 2010

Mental Training Through Meditation Enhances Attentional Stability

A. Lutz, H. Slagter, et al.
Article in Journal of Neuroscience

Abstract
The capacity to stabilize the content of attention over timevaries among individuals, and its impairment is a hallmark ofseveral mental illnesses. Impairments in sustained attentionin patients with attention disorders have been associated withincreased trial-to-trial variability in reaction time and event-relatedpotential deficits during attention tasks. At present, it isunclear whether the ability to sustain attention and its underlyingbrain circuitry are transformable through training. Here, weshow, with dichotic listening task performance and electroencephalography,that training attention, as cultivated by meditation, can improvethe ability to sustain attention. Three months of intensivemeditation training reduced variability in attentional processingof target tones, as indicated by both enhanced theta-band phaseconsistency of oscillatory neural responses over anterior brainareas and reduced reaction time variability. Furthermore, thoseindividuals who showed the greatest increase in neural responseconsistency showed the largest decrease in behavioral responsevariability. Notably, we also observed reduced variability inneural processing, in particular in low-frequency bands, regardlessof whether the deviant tone was attended or unattended. Focusedattention meditation may thus affect both distracter and targetprocessing, perhaps by enhancing entrainment of neuronal oscillationsto sensory input rhythms, a mechanism important for controllingthe content of attention. These novel findings highlight themechanisms underlying focused attention meditation and supportthe notion that mental training can significantly affect attentionand brain function.

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October 21, 2010

Could an Experimental Memory Drug Put an End to “Senior Moments”?

From: Discover Magazine Online:

A new drug seems to be able to reverse normal age-related memory decline in old mice–like a face-lift for neurons, bringing them back to their younger days. The results of the experimental treatment, which works by blocking certain stress hormones, were published in the Journal of Neuroscience.

“What’s most surprising is that even short-term inhibition was able to reverse memory loss in old mice,” says Jonathan Seckl, a professor of molecular medicine who was involved in the research. “I don’t think people had realized this was so reversible. It takes [the animals] back to being relatively young.” [Technology Review].

Research has shown that stress hormones called glucocorticoids play a role in memory loss, by damaging the brain over time. But targeting the glucocorticoids themselves is dangerous, because reducing their levels would leave the body without a stress response. The researchers therefore targeted an enzyme instead, which activates the hormone in neurons.

Click here for the complete article.

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October 5, 2009

Causal role of prefrontal cortex in the threshold for access to consciousness

attention,brain injury,perception — alice @ 12:36 am

A. Del Cul, S. Dehaene, P. Reyes, E. Bravo, A. Slachevsky
Article in Brain

Abstract
What neural mechanisms support our conscious perception of briefly presented stimuli? Some theories of conscious access postulate a key role of topdown amplification loops involving prefrontal cortex (PFC). To test this issue, we measured the visual backward masking threshold in patients with focal prefrontal lesions, using both objective and subjective measures while controlling for putative attention deficits. In all conditions of temporal or spatial attention cueing, the threshold for access to consciousness was systematically shifted in patients, particular after a lesion of the left anterior PFC. The deficit affected subjective reports more than objective performance, and objective performance conditioned on subjective visibility was essentially normal. We conclude that PFC makes a causal contribution to conscious visual perception of masked stimuli, and outline a dual-route signal detection theory of objective and subjective decision making.

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May 19, 2009

Learning, Arts, and the Brain: the Dana Consortium Report on Arts and Cognition

From the Dana Foundation: The Dana Foundation released at a news conference on March 4, Learning, Arts, and the Brain, a three-year study at seven universities, which finds strong links between arts education and cognitive development. Speakers included Michael Gazzaniga, Ph.D., UC, Santa Barbara; Michael Posner, Ph.D., University of Oregon;  Elizabeth Spelke, Ph.D., Harvard University  and Brian Wandell, Ph.D., Stanford University.  Guy Mckhann, M.D., Johns Hopkins University gave a summary and Dana Gioia, chairman of the National Endowment for the Arts spoke of the study’s importance to the field of education.

Click here for the webcast archive.

Click here for the event transcript.

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November 24, 2008

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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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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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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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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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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October 11, 2008

Comparison of event-related potentials in attentional blink and repetition blindess

EEG,attention — alice @ 4:44 pm

In a recent study, Mika Koivisto and Antti Revonsuo compared the timing and mechanisms of attentional blink (AB) and repetition blindness (RB) directly during the same rapid serial visual presentation stream to examine the relation between the two phenomena.  To do so, they recorded electrophysiological responses over the scalp (EEG, ERP) to repeated and unrepeated targets.

The authors report the following findings:

Comparable to earlier ERP studies on visual awareness, the results showed for both types of targets a negative amplitude difference between ERPs to consciously recognized and unrecognized targets during 250-350 ms from stimulus onset, suggesting that both AB and RB are associated with deficits of conscious perception, occurring at earlier stages than access to working memory. However, the perceptual deficit in RB is more severe, which may be related to higher overall negativity in response to repeated targets observed 150-300 ms after stimulus onset, suggesting stronger cortical baseline activation and higher perceptual threshold for repeated targets as compared with unrepeated ones.

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July 15, 2007

Attention and consciousness: two distinct brain processes

attention,perception — alice @ 10:09 pm

Abstract of Attention and consciousness: two distinct brain processes, in TRENDS in Cognitive Sciences.

The close relationship between attention and consciousness has led many scholars to conflate these processes. This article summarizes psychophysical evidence, arguing that top-down attention and consciousness are distinct phenomena that need not occur together and that can be manipulated using distinct paradigms. Subjects can become conscious of an isolated object or the gist of a scene despite the near absence of top-down attention; conversely, subjects can attend to perceptually invisible objects. Furthermore, top-down attention and consciousness can have opposing effects. Such dissociations are easier to understand when the different functions of these two processes are considered. Untangling their tight relationship is necessary for the scientific elucidation of consciousness and its material substrate.

For full access to this paper, click here.

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June 15, 2007

Learning to pay attention

EEG,altered states,attention — thomasr @ 3:20 am

attention_plos.jpgBy Rachel Jones

Our sensory system is constantly bombarded with inputs, but owing to the brain’s finite processing power, we are forced to pay attention to only a tiny proportion of these inputs at any given time. In a new study, Richard Davidson and colleagues report [in PLoS Biology] that intensive training in meditation can alter the way in which the brain allocates attentional resources to important stimuli, allowing people to improve their performance on a demanding visual task.

In the “attentional blink” task, volunteers were asked to identify two “target” stimuli—for example, two particular numbers—in a stream of rapidly presented “non-target” stimuli—for example, letters—which are irrelevant to the task. When the first target number appears on the screen, it captures the attention of the subject, and this can prevent the person from spotting the second target if it appears within around half a second of the first (the attentional blink). It is as if the brain is so busy processing the first target that it can’t also process the second, and therefore the second target goes unnoticed. However, the attentional blink does not represent a structural processing bottleneck. Most subjects are able to spot the second target on at least a small proportion of trials. Since this task gauges the ability of subjects to allocate cognitive resources efficiently when multiple stimuli compete for attention, it is perfectly suited for investigations of the effects of mental training on attention.

Read full story at PLoS Biology

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Neural Mechanisms of Visual Attention: How Top-Down Feedback Highlights Relevant Locations

attention.jpgAttention helps us process potentially important objects by selectively increasing the activity of sensory neurons that represent the relevant locations and features of our environment. This selection process requires top-down feedback about what is important in our environment. We investigated how parietal cortical output influences neural activity in early sensory areas. Neural recordings were made simultaneously from the posterior parietal cortex and an earlier area in the visual pathway, the medial temporal area, of macaques performing a visual matching task. When the monkey selectively attended to a location, the timing of activities in the two regions became synchronized, with the parietal cortex leading the medial temporal area. Parietal neurons may thus selectively increase activity in earlier sensory areas to enable focused spatial attention.

Science

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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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February 1, 2007

What do we hear with our eyes?

Would we hear things differently if we always kept our eyes closed? The answer is yes! The McGurk Effect is a classic illustration of how the spoken sounds we hear are influenced by whether or not we can see the speaker’s lips.

Click here for a great online example of the McGurk Effect. In this online example, we see a person saying (making lip movements for) “GA GA”, but in reality, we are hearing “BA BA”. When these sounds and lip movements are combined, most adults think that they are hearing “DA DA”.

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January 17, 2007

The Multi-Source Interference Task

attention,brain networks,fMRI — alice @ 11:35 pm

Abstract of The Multi-Source Interference Task: an fMRI task that reliably activates the cingulo-frontal-parietal cognitive/attention network, in Nature.

In this protocol we describe how to perform the Multi-Source Interference Task (MSIT), a validated functional magnetic resonance imaging (fMRI) task that reliably and robustly activates the cingulo-frontal-parietal cognitive/attention network (CFP network) within individual subjects. The MSIT can be used to (i) identify the cognitive/attention network in normal volunteers and (ii) test its integrity in people with neuropsychiatric disorders. It is simple to perform, can be completed in less than 15 min and is not language specific, making it appropriate for children, adults and the elderly. Since its validation, over 100 adults have performed the task. The MSIT produces a robust and temporally stable reaction time interference effect (range 200–350 ms), and single runs of the MSIT have produced CFP network activation in approximately 95% of tested subjects. The robust, reliable and temporally stable neuroimaging and performance data make the MSIT a useful task with which to study normal human cognition and psychiatric pathophysiology.

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December 30, 2006

Visuo-spatial consciousness and parieto-occipital EEGs

Which brain areas are involved in visuospatial consciousness? In a recent study by Babiloni and colleagues, subjects performed a visual perception task. Interestingly, these scientists found that visual-evoked potentials at parieto-occipital areas had the same peak latencies for cases of conscious, as well as unconscious, perception. These visual-evoked potentials were located to the occipital (BA 19) and parietal (BA 7) cortices.

Source strength was significantly stronger in consciously, compared to unconsciously, perceived cases at about +300 ms poststimulus. Babiloni and colleagues concluded that these features of the observed parieto-occipital activation might be connected to visuospatial consciousness.

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December 17, 2006

The impact of invisible stimuli

invisible.png

The more clear a stimulus is, the more distracting it can be. Or so you might think. In a recent Science publiation Tsushima et al. report that weak stimuli that are irrelevant to the task being performed—have
a greater impact than strong, easily noticeable distractors.

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