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Archive for the ‘neuroscience’ Category

face recognition in the brain

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One of my heroes in the field of neuroscience is Wilder Penfield. He pioneered the use of electrical stimulation of the brain, prior to surgery for treating epilepsy. The goal was to identify brain functions in the areas surrounding the locus of epilepsy and spare as much tissue as possible, if critical functions had been identified. The most remarkable part of this exercise was that the patient was fully conscious (although under a local anesthetic) and could verbally report sensations and perceptions experienced by the electrical stimulation of the probes. This technique contributed enormously to deriving functional maps of the human brain.

Penfield’s legacy is alive and well.  A couple of days ago, ScienceNow website reported on a study published in the Journal of Neuroscience.  By using techniques similar to Penfield’s, scientists at Stanford Univ, were able to determine the precise locus of face recognition in humans. Huffington Post has also included a really remarkable video of the patient’s experience as he is being stimulated by electrical current.  You must watch it!

That our three pound universe is a constructed reality, is on ample display in the video. Soul theorists, go figure!

What lay people may not appreciate, in this story and the video, is that our ability to recognize faces is confined to a small piece of our cerebral cortex. Destroying this piece of brain tissue only knocks out face recognition. One can still recognize objects (in the video, the perception of the scientist’s suit and tie is not distorted.) In fact, back in graduate school, I had the privilege of meeting a person, who due to an accident in early childhood, lost the ability to recognize faces, even his own! His non-face object perception was intact. He used salient features like a mustache, glasses, or other unique feature to remember and identify people he met.

This study and the video gave me the cognitive high for the day.

Written by asterix98

October 25, 2012 at 6:24 am

Subjectivity of our existence

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As computer users, we are all familiar with the “sleep” or “hibernate” function. Essentially, the computer maintains its current state while “powering down” different parts of the system to conserve power. When you “wake up” the computer, it lets you pick up what you were doing from where you left off. The “sleep” and “wake” nomenclature for this behavior is not happenstance but is a direct analogy to how brains function. But there is one crucial difference. In computers, it is a very well understood process. The current state of the system is stored in non-volatile memory and reinstated on waking up. In brains, this analogous process has the magical property of consciousness – subjectivity.  Below I have excerpted a  passage from Antonio Damasio’s book – The Self Comes to Mind,  that  beautifully captures the essence of this difference (if you had not thought of it in these terms, it will be a true wake up call – sorry, I could not help the pun).

“….We all have free access to consciousness, bubbling so easily and abundantly in our minds that without hesitation or apprehension we let  it be turned off every night when we go to sleep and allow it to return every morning when the alarm clock rings, at least 365 times a year, not counting naps. And yet few things about our beings are as remarkable, foundational, and seemingly mysterious as consciousness. Without consciousness-that is, a mind endowed with subjectivity-you would have no way of knowing that you exist, let alone know who you are and what you think. Had subjectivity not begun, even if very modestly at first, in living creatures far simpler than we are, memory and reasoning are not likely to have expanded in the prodigious way they did, and the evolutionary road for language and the elaborate human version of consciousness we now possess would not have been paved. Creativity would not have flourished. There would have been no song, no painting, and no literature. Love would never have been love, just sex. Friendship would have been mere cooperative convenience. Pain would never have become suffering-not a bad thing, come to think of it but an equivocal advantage given that pleasure would not have become bliss either. Had subjectivity not made its radical appearance, there would have been no knowing and no one to take notice, and consequently there would have been no history of what creatures did through the ages, no culture at all.”

The discovery of mirror neurons in the early nineties and subsequent research to understand their role in social cognition is offering tantalizing insights into the neural substrates underlying this subjectivity – the hallmark of human existence.

Written by asterix98

September 8, 2012 at 6:52 pm

Of molecules and (wo)men

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In this past weekend’s edition of WSJ review, the following article appeared

The Trust Molecule

(click above to go to article)

Why are some of us caring and some of us cruel, some generous and some greedy? Paul J. Zak on the new science of morality— and how it could be used to create a more virtuous society

The basic message is oxytocin can foster trust and increase social bonding. Zak writes “…oxytocin orchestrates the kind of generous and caring behavior that every culture endorses as the right way to live—the cooperative, benign, pro-social way of living that every culture on the planet describes as “moral.” The Golden Rule is a lesson that the body already knows, and when we get it right, we feel the rewards immediately….”

This all sounded very good and seemed like the only thing left for us to do was inject ourselves with oxytocin and the whole world would be one large Berkeley hippie commune. Obviously, this would be too easy. I was not entirely satisfied and tried to find out what others had to say on this topic. I found this on the APA site “…

Oxytocin has been on a joy ride for 20 years, ever since animal studies first linked the hormone to bonding between mother and newborn, as well as between mating adults. Dubbed the “cuddle” or “love” hormone by the popular press, more recently it has earned attention for its role in promoting trust.

One company, Vero Labs in Boca Raton, Fla., has even put it in a cologne-like spray, marketed as “Liquid Trust”: Fifty dollars buys a two-month supply that promises consumers “confidence in a bottle,” according to its website….”

Oxytocin doses seem to help children with autism cope much better socially. But some researchers warn that it does have a darker side. From the same APA article …”More evidence of oxytocin’s downside comes from Mount Sinai School of Medicine psychologist Jennifer Bartz, PhD. In a study published online in November in Social Cognitive and Affective Neuroscience, she and her colleagues examined whether oxytocin might boost trust and cooperation, as measured with a well-studied economic game, among men and women with borderline personality disorder, who tend to have volatile relationships. She found that rather than increasing trust and teamwork, a dose of oxytocin decreased those feelings compared with a placebo.”

While the jury is still out on the how, why and what of oxytocin, Zak has happily dubbed it the “moral” molecule and in new age style advocates a bunch of behaviors that can enhance social bonding, hugs being his most favorite one. I have to note here that as I was reading these articles, I was reminded of this lady who is fondly referred to as Amma(Mother), by her followers. She apparently can heal, just by hugging and touching. In fact, the byline on her website (link above) says – Embracing the World. The oxytocin definitely must be free flowing in that commune.

Another chemical doing the rounds in the news is dopamine. Researchers have figured out the more adventurous (“scout”)bees in a colony have lower amounts of dopamine making them less averse to novel experiences. Incidentally, in humans it is just the opposite, higher dopamine levels lead to novelty seeking behaviors. As Spock would say, Fascinating!

Written by asterix98

May 3, 2012 at 1:08 am

Neuroscience and the law

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Michael Gazzaniga, a Professor of Neuroscience at UC Santa Barbara, is considered the father of Cognitive Neuroscience. This was a nascent discipline when I entered graduate school, in the early 90s. Since then it has blossomed into a vibrant area of scientific inquiry and has revealed much about the functional/systems neuroscience of the brain. Specifically, functional MRI as a research tool, has been instrumental in helping neuroscientists peer into the inner workings of the brain. This has spawned many sub disciplines including neurotheology, but the most insidious offshoot is neuromarketing: the pursuit of research specifically targeted at influencing buying behavior. Out of curiosity, I participated in one such study in Berkeley, and got paid $100 for it!!

Nevertheless, all of this exciting new information about the brain has also caught the attention of the judicial system. Gazzaniga has been involved in helping people in the legal profession understand the ramifications, of the state of the art brain research, for defendants: juvenile delinquents to psychopaths. The crux of the problem is this: neuroscience tells us that there is really no such thing as free will, so if the “hardware” drives certain people to commit heinous crimes, who is responsible for these actions? In fact, his new book on the topic is entitled – Who’s in charge? . You can also watch his very interesting lecture on the same topic at the Edge.org:Neuroscience and Justice .  In a sense, the upshot is, as Hobbes noted,  as a society, without some commonly agreed upon rules, left to our own devices, we would be at each other’s throats. Given the new insights into the nature of free will, how should the existing social contracts be upgraded? This is a topic of discussion for society at large.

Written by asterix98

November 24, 2011 at 5:51 pm

Posted in neuroscience

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Pain is inevitable, suffering is an option

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In an earlier post, I had discussed an essay titled It’s a Beautiful Life. The author’s main point serves as the title of this blog. In some sense, she was pointing out that you do have control over the “experience of pain”. Today, I read an article entitled “Rewiring the Brain to Ease pain” . It opens with “how you think about pain can have a major impact on how it feels”. Much of this is borne out by a bunch of recent neuroscientific studies as well as “mind-body” therapies. Other techniques include meditation and distraction.

Behold the power of the “mind”.

Written by asterix98

November 16, 2011 at 6:54 am

Traumatic brain injury

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Here is an interesting NYTimes opinion piece – Starting again after a Brain Injury . The author shares here experiences after an accident that left her quite debilitated cognitively and physically. She talks about a complete change in personality, loss of memory, disrupted cognitive social map,  and coping with the world anew after 45 yrs in existence! She is somewhat more fortunate (or is she ?) than the famous neurological case of Phineas Gage.

Because of the injury, her cognitive apparatus, responsible for weaving her past, present and future  into a coherent canvas, is now in disarray, mostly cutting her loose from her past, resulting in the loss of all of her anchors, her bearings. Much of the narrative is about her journey piecing together her life again. Less poignant and more resolute.

 

 

 

Written by asterix98

October 16, 2011 at 5:10 pm

The tell-tale human brain

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I just finished reading a book entitled “The tell-tale human brain” by V.S.Ramachandran. [For those of you who do not know the name, Ramachandran, is a world renowned neuroscientist. He is a remarkably gifted scientist and has conducted many path breaking studies that have significantly advanced the status quo in our understanding of the human brain. Some people even think he may be a Nobel prize candidate for his pioneering work in neuroscience]. His research is one of the contributing causes to the many neuroX subdisciplines (neurotheology, neuroeconomics, neuromarketing to name a few) that have mushroomed in academia and industry.

This book is a good synthesis of much of his research. If you ignore his not so great sense of humor and sometimes chest beating, there is a lot of great material in the book to ponder on. What I love about his books is his rich catalog of neurological patients and their attendant deficits. Through their abnormalities, we are lead to an understanding of the inner workings of a normal human brain.  My favorite is the “god center” located in the temporal lobes. Patients with temporal lobe epilepsies see visions of god!! [My advisor used to say, irreverently, that the claims of received wisdom from God are actually manifestations of a hallucinating brain. I must say I agree with him.]

Some of the topics include mirror neurons and their role in social cognition, neural plasticity, synesthesia (blending of the senses), impostors moms and dads. It is utterly fascinating when we consider the remarkable insight that our unified percept of the external reality is really the orchestration of many interacting functionally specific brain modules [the timing and sychronization of these processes are also extensively studied topics in neuroscience]. Blindsight, a phenomenon, described in some detail, will make you wonder about what we really mean when we talk about consciousness.

Ultimately, the book is about what sets humans apart in the animal kingdom. The book format allows the author to speculate a great deal. If you pick this book up, I urge you to do so with a fairly wide open mind.

Written by asterix98

August 3, 2011 at 2:38 pm

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