Neuroscience for Beginners

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Neuroscience for Beginners

Postby ashley72 » Fri Oct 26, 2012 4:45 am

I found this talk by Bradley Voytek - a young neuroscientist a good introduction to the field. It only goes for about 17 minutes but was very interesting and insightful.

http://www.youtube.com/watch?feature=player_embedded&v=ki24i6NPic0
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Re: Neuroscience for Beginners

Postby ashley72 » Fri Oct 26, 2012 5:50 am

In this video Michael Posner discusses the different diagnostic tools neuroscientists used to understand the brain. Goes for about 16 mins.

http://www.youtube.com/watch?v=eFmKUQSKDXc&feature=relmfu

The diagnostic tools he would like to have in the future would need to do the following.

1. Measure the activity of single cells in non-invasive way.
2. The expression of different gene's within different parts of the brain in a non-invasive way. We could look at how gene expression occurs in the anterior cingulate in relationship to tasks.
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Re: Neuroscience for Beginners

Postby ashley72 » Sat Oct 27, 2012 10:20 pm

How Neural Networks Lean By A Process Of Trial & Error

This is a great introduction to neural networks, these kind of computer networks are designed to mimick the way biological neural networks function. However, biological neural networks are still poorly understood due to there enormous complexity and difficulty diagnosing non-invasively. This short video is merely an introduction to how neural networks learn using weighted hidden nodes through a very slow process of trial & error using feedback loops.

http://youtu.be/DG5-UyRBQD4
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Re: Neuroscience for Beginners

Postby Sighclone » Mon Oct 29, 2012 7:27 pm

The latest research via fMRI on deep-level brain tissue activity suggests that the default-mode-network gets shut down by psilocybin, just like it does by years of meditation. Gary Weber gave his talk at SAND IV last Friday on this:

http://www.pnas.org/content/early/2012/ ... 9.abstract

Andy
A person is not a thing or a process, but an opening through which the universe manifests. - Martin Heidegger
There is not past, no future; everything flows in an eternal present. - James Joyce
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Re: Neuroscience for Beginners

Postby smiileyjen101 » Mon Oct 29, 2012 10:20 pm

http://www.npr.org/templates/story/stor ... =110997741

I was reading this article yesterday. Showing different resonances of brain activity. The Theta correlations are interesting.

No mushrooms involved ; )
Our rights start deep within our humanity; they end where another's begin~~ SmileyJen
http://www.balancinginfluences.com
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Re: Neuroscience for Beginners

Postby ashley72 » Mon Oct 29, 2012 10:35 pm

Sighclone wrote:The latest research via fMRI on deep-level brain tissue activity suggests that the default-mode-network gets shut down by psilocybin, just like it does by years of meditation. Gary Weber gave his talk at SAND IV last Friday on this:

http://www.pnas.org/content/early/2012/01/17/1119598109.abstract

Andy


Andy,

Great post. default-mode-network = mind wandering

IMO selective control of attention (attention-regulation) stops or prevents our attentional focus wandering into the neural network which controls self-referential reflections (mind wandering).

Meditation & certain drugs can inhibit or excite our selective attention.

This attention training program I've found very helpful in relation to better understanding my selective attention.

http://youtu.be/OtYYcWJcZas

I've been practising this attention program twice daily for about a month with good results. It works a lot like meditation. In some sessions I feel extremely relaxed even though I'm listening to all these sounds. Memories, thoughts, distractions arise as usual, which lead your attention astray momentarily, but the guided exercise brings you back to attending to the sound.

If our selective attention is like a muscle/function, it needs to be strengthened when its condition is impaired.

Eckhart Tolle meditation practices promote better control of our selective attention function. The only difference is his guided meditations ask us to attend to the stillness, inner body etc. IMO it doesn't matter what you attend to as long as the attention merely stays on the object without introspecting or wandering about.

Here is a Eckhart Tolle guided meditation. The only big difference between the two selective attention practices is the spiritual connotations.

http://youtu.be/1sQ0DTF2tAM
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Re: Neuroscience for Beginners

Postby ashley72 » Tue Oct 30, 2012 4:44 am

This is a good article which talks about the default-network called "Self Referential Thought: A Neuro-Scientific Perspective".

http://www.fairobserver.com/article/self-referential-thought-neuro-scientific-perspective

The Default Network appears to be responsible for task-independent introspection, or self-referential thought. Put differently, whenever an individual engages in thoughts associated with him or herself, this particular network of brain regions is activated. Scientists suggest that the Default Network may be required for generating spontaneous thoughts during mind-wandering, and that it may be an essential component for creativity. More specifically, it becomes active when individuals focus on internal tasks, such as daydreaming or envisioning the future.

Another interesting article which relates social anxiety to the default network.

http://www.ncbi.nlm.nih.gov/pubmed/19559343


The role of the default-Mode-Network in social cognition, we suggest that its impairment in the default-Mode-network in Social Phobia Patients might be relevant in the development of the feeling of wariness of others' judgment and may be related to the so-called self-focused attention. Self-focused attention is the awareness of self-referent information, and is present in many emotional disorders and may additionally prevent individuals from observing external information that could disconfirm their own fears. Moreover, the abnormal modulation of activity in the Default-Mode-Network may reflect persistent rumination or anxiety-related thoughts that are not modulated by the switch from rest to task.

My hunch is that socially anxious people activate their default-mode-network more often than people who are not socially anxious. The only way to prevent this habit, is to strengthen their selective attentional control. Any selective attention task needs to stay focussed on the external factors, conversations, planning & things occurring in the moment. Rather than have the attentional focus wander off into the default-mode-network and start ruminating about self-referent information.
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Re: Neuroscience for Beginners

Postby ashley72 » Tue Oct 30, 2012 11:04 pm

This is a two part talk by Gary Webber at the science & non-duality conference (SAND) in 2011.

He discusses the default-mode-network, mind-wandering & how meditation practices can de-activate mind-wandering (default-mode).

He also presents fMRI studies which show which regions of the brain get activated.

No Thoughts, No Time, Part I - Gary Weber

No Thoughts, No Time, Part II - Gary Weber
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Re: Neuroscience for Beginners

Postby ashley72 » Sat Nov 03, 2012 3:35 am

Marcus Raichle is a neurologist at the Washington University School of Medicine in Saint Louis. He is a professor in the Department of Radiology with joint appointments in Neurology, Neurobiology and Biomedical Engineering. His research over the past 40 years has focused on the nature of functional brain imaging signals arising from PET and fMRI and the application of these techniques to the study of the human brain in health and disease.

Here Marcus talks about the default mode network. Video 6:31 min

http://youtu.be/uZgOUAtwUA8
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Re: Neuroscience for Beginners

Postby Sighclone » Sun Nov 04, 2012 5:07 am

Thanks, Ash...interesting discussion re DMN and depression.

Gary's latest talk (October 27, 2012) included discussion of an article in PNAS for February 7, 2012, abstract below:

Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin

Robin L. Carhart-Harrisa,b, David Erritzoea,c, Tim Williamsb, James M. Stonea, Laurence J. Reeda, Alessandro Colasantia, Robin J. Tyackea, Robert Leechd, Andrea L. Maliziab, Kevin Murphye, Peter Hobdene, John Evanse, Amanda Feildingf, Richard G. Wisee, and David J. Nutta,b,1aNeuropsychopharmacology Unit,dImperial College London, London W12 0NN, United Kingdom;bAcademic Unit of Psychiatry, University of Bristol, Bristol BS8 2BN, United Kingdom;eBrain Research Imaging Centre, Cardiff University, Cardiff CF10 3AT, United Kingdom;fThe Beckley Foundation, Beckley Park, Oxford OX3 9SY, United Kingdom; andcNeurobiology Research Unit, Rigshospitalet, and Center for Integrated Molecular Brain Imaging, University of Copenhagen, DK-2100 Copenhagen, Denmark

Edited by Leslie Lars Iversen, University of Oxford, Oxford, United Kingdom, and approved December 20, 2011 (received for review December 3, 2011)

Abstract Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.

Gary has suggested that the state of consciousness we label as satori, kensho or even samahdi can be duplicated for a brief period by psychoactive chemicals. The fMRI scans certainly appear similar to the shift to an alternate DMN in meditation states observed by Jud Brewer at Yale:

PNAS November 23, 2011:

Meditation experience is associated with differences in default mode network activity and connectivity
Judson A. Brewera,1, Patrick D. Worhunskya, Jeremy R. Grayb, Yi-Yuan Tangc, Jochen Weberd, and Hedy Kobera
aDepartment of Psychiatry, Yale University School of Medicine, New Haven, CT 06511;bDepartment of Psychology, Yale University, New Haven, CT 06510;cDepartment of Psychology, University of Oregon, Eugene, OR 97403; anddDepartment of Psychology, Columbia University, New York, NY 10027
Edited by Marcus E. Raichle, Washington University in St. Louis, St. Louis, MO, and approved October 4, 2011 (received for review July 22, 2011)

Abstract
Many philosophical and contemplative traditions teach that “living in the moment” increases happiness. However, the default mode of humans appears to be that of mind-wandering, which correlates with unhappiness, and with activation in a network of brain areas associated with self-referential processing. We investigated brain activity in experienced meditators and matched meditation-naive controls as they performed several different meditations (Concentration, Loving-Kindness, Choiceless Awareness). We found that the main nodes of the default-mode network (medial prefrontal and posterior cingulate cortices) were relatively deactivated in experienced meditators across all meditation types. Furthermore, functional connectivity analysis revealed stronger coupling in experienced meditators between the posterior cingulate, dorsal anterior cingulate, and dorsolateral prefrontal cortices (regions previously implicated in self-monitoring and cognitive control), both at baseline and during meditation. Our findings demonstrate differences in the default-mode network that are consistent with decreased mind-wandering. As such, these provide a unique understanding of possible neural mechanisms of meditation.

The fMRI patterns from both studies were shown as a Powerpoint presentation in Gary's recent SAND talk and they look almost identical.

Implications of this research remain to be explored.

Andy
A person is not a thing or a process, but an opening through which the universe manifests. - Martin Heidegger
There is not past, no future; everything flows in an eternal present. - James Joyce
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Re: Neuroscience for Beginners

Postby ashley72 » Sun Nov 04, 2012 6:13 am

Hi Andy,

Thanks for that. I'd come across the second study you posted a few days ago.

Have you heard of the retired neurologist Dr James Austin?

He gave this interesting talk at Google which may interest you. It's quite a technical talk on brain functioning and how it might also relate to meditation.

http://youtu.be/vEIXijQctlQ
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Re: Neuroscience for Beginners

Postby runstrails » Sun Nov 04, 2012 4:13 pm

Thanks, Andy. If I'm reading the abstracts correctly--in the first study there is a decoupling between posterior cingulate (PC) and pre-frontal (PFC) areas during the psychedelic 'satori' states, while in the second study there is an increased coupling between PCC and PFC areas during meditation states. Did Gary address this seeming discrepancy? If not, no worries, this can be typical of fMRI research sometimes. (and I've not bothered to read the entire articles either, of course).
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Re: Neuroscience for Beginners

Postby ashley72 » Tue Nov 06, 2012 1:38 am

The blue pathway represents the Egocentric pathway. The red pathway represents the Allocentric (other) pathway. This illustration is relevant to James Austin's talk.

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Re: Neuroscience for Beginners

Postby Sighclone » Thu Nov 08, 2012 3:53 am

rt -

Activity (apart from coupling) in the mPFC and PCC is typical and a key part of the DMN during "selfing" or the "blah-blah" constant stream of thoughts for most people. Activity in these areas deceased during meditation and psilocybin use. An increase in activity in the dACC and dlPFC was noted during meditation in the Yale study, sugesting a new DMN occurs during meditation. Also, the 10,000-hour Theravadan Buddhist meditators in the Yale study showed a baseline state (when "not meditating") which had much more dACC and dlPFC activity than the controls. The suggestion was that a new DMN is part of awakening. I also did not read the articles and do not know how they use the word "coupling."

A recent post on Gary's blog discusses this further:

http://www.happinessbeyondthought.blogs ... chnew.html

Andy
A person is not a thing or a process, but an opening through which the universe manifests. - Martin Heidegger
There is not past, no future; everything flows in an eternal present. - James Joyce
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Re: Neuroscience for Beginners

Postby ashley72 » Sun Aug 18, 2013 1:29 pm

This is great TED talk on the recent use of deep brain stimulation as a treatment for a variety of neurological diseases and disorders.

This technique allows neurosurgeons to insert electrodes into specific locations within the brain. The electrodes stimulate the area and alleviate the disturbance.

The neuroscientists have been identifying & pinpointing disturbed brain regions using fMRI imaging.

Its estimated 100,000 patients, the huge majority with Parkinson's disease, have been treated with DBS to date..... not an insignificant number!


http://www.ted.com/talks/andres_lozano_parkinson_s_depression_and_the_switch_that_might_turn_them_off.html

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