Reduced Neural Selectivity Increases fMRI Adaptation with Age during Face Discrimination

Key project finally published! This took quite a while, but it was worth it.

[Link to article if you have journal access]
[Link to Pubmed abstract access]

By Joshua O., Goh , Atsunobu, Suzuki , Denise C., Park
Beckman Institute, University of Illinois, Urbana-Champaign, IL, USA; Center for Vital Longevity, University of Texas, Dallas, TX, USA.

Ventral-visual activity in older adults has been characterized by dedifferentiation, or reduced distinctiveness, of responses to different categories of visual stimuli such as faces and houses, that typically elicit highly specialized responses in the fusiform and parahippocampal brain regions respectively in young adults (Park et al., 2004). In the present study, we demonstrate that age-related neural dedifferentiation applies to within-category stimuli (different types of faces) as well, such that older adults process less distinctive representations for individual faces than young adults. We performed a functional magnetic resonance imaging adaptation experiment while young and older participants made same-different judgments to serially presented face-pairs that were Identical, Moderate in similarity through morphing, or Different. As expected, older adults showed adaptation in the fusiform face area (FFA), during the Identical as well as the Moderate conditions relative to the Different condition. Young adults showed adaptation during the Identical condition, but minimal adaptation to the Moderate condition. These results indicate that older adults' FFA treated the morphed faces as Identical faces, reflecting decreased fidelity of neural representation of faces with age.

NeuroImage, In Press, Accepted Manuscript, Available online 6 February 2010

Origami and the Brain

Origami. The art of folding paper into shapes using a single sheet of paper without tearing or cutting. Perhaps, at an abstract level, this may be likened to what our brains do. We have one brain. We can't make big changes to it, like take one part of the brain and manually "connect" it to another part of the brain. Rather, we have to work within the limits of certain neural connection rules to establish a certain way to get to an end state.

For example, some rules may be related to the fact that our neurons have many short range local connections with neighboring neurons, as well as, some long range connections to more distant groups of neurons. Establishing and pruning these connections is dependent on time and stimulation from external as well as internal events. These events can be cognitive or biological or physical (e.g. the intention to retrieve a memory, or some neurotransmitter regulation, or some visual energy input, respectively). Within this system, our brains try to represent external information, and to generate certain actions or responses.

In a similar manner, in origami, each fold is like an imprint of an event that happens. The effect of folding, however, is limited by the thickness, elasticity, and size of the paper, as well as the force of the folding. Folding could be a sharp strong crease, a light depression, or a curve. Folding also occurs along specific lines or regions on the paper at a time. Finally, folding has temporal order. Through a combination of these factors, the paper encodes what forces have been exerted on it, and represents all of that in a particular physical form. The end state.

The end state maybe be a meaningful shape, or it may have a meaningful function. We can transform a simple piece of paper into a form of a crane, or a box, or a really complex shape (origami experts have been able to do wonders!). We can even use the tension inherent in the folded paper as a spring with tremendous kinetic energy when released. We can also use folding to allow a large piece of material that ordinarily would not fit in specific area to conform to the shape and therefore fit in the area.

Likewise, the brain performs an interesting function in incorporating sensory information from the physical world and representing all the rich material within a single piece of organic tissue. This "folding" of information from one state to another may be a framework to understand neural function.

Consider that we can quantify the physical forces and characteristics of a piece of paper and its folds. Based on low level parameters, we can then determine what the origami will look like, what it can do, what properties its resulting form maintains. Applying a similar method to parameterize neural function may allow us to better describe how the properties of the brain relate to cognition and behavior. For example, the ease with which a paper folds may be dependent on the thickness of the paper (for a given material elasticity/rigidity/brittleness). This will in turn determine how much force must be applied to the paper to achieve a fold of a certain angle. In the same way, one property of the brain may be how strong the connections in a certain neuronal region may be. The stronger the connections, the easier it may be for a signal in one region to affect the activity in another. Another case in point, the brain maintains a certain level to generate new neurons in key parts of the cortex. Neurogenesis is known to occur even in late adulthood in the hippocampus and the peri-ventricular walls. Importantly, recent studies have shown that neurogenesis may be helpful in overcoming drug addiction. A possible mechanism might be that the new neurons enable the brain to represent existing addiction behaviors (information "folding"), in a new way that discourages addiction [link to relevant post]. Moreover, it is possible that different individuals have different rates, or ability, of neurogenesis, and external events or neurochemical interventions may also encourage neurogenesis. It is this rate of neurogenesis that might be a candidate parameter that determines how much a particular brain can fold.

Of course, this is all analogical. There is no necessary association between paper and brain. But, this presents an interesting way to approach the problem of quantifying brain function. Paper folding has been applied to several interesting real life problems. For example, the folding of solar-energy panels into a satellite so that large plates fit into a small structure for launching, and unfold in space to achieve maximum surface area for efficient energy collection. In addition, protein folding occurs according to the electro-chemical forces at the molecular level. Paper folding has been applied to understanding and even manipulating these forces to make protein molecules that achieve specific helpful biomolecular functions. Here's an example of applying origami to practical problem from an MIT group [link].

After all, the reason why origami is meaningful, is because we perceive cranes in a few simple folds.

The Automation of Science

Article from Science:

[REPORTS] The Automation of Science
"A robot scientist discovers orphan enzymes that take part in yeast metabolism."

This was published a while ago. But it may be worth mentioning because it could be the pivotal moment in AI.

Increasing neurogenesis might prevent drug addiction and relapse

Article from ScienceDaily:

Increasing neurogenesis might prevent drug addiction and relapse
"Researchers hope they have begun paving a new pathway in the fight against drug dependence."

This makes computational sense. Adding new neurons creates the possibility of forming new inhibitory connections, as well as de-potentiating the strength, or contribution, of existing ones. Such predifferentiated neurons serve as fresh unwritten computational space for which new behaviors and cognitions can be learned. In addition, old pathways which have been entrained and which are hard to change (because of prolonged experience or intensity) can have their effects counterbalanced.

New Year Thoughts

"Beloved, let us love one another, for love is of God; and everyone who loves is born of God and knows God. He who does not love does not know God, for God is love. In this the love of God was manifested toward us, that God has sent His only begotten Son into the world, that we might live through Him. In this is love, not that we loved God, but that He loved us and sent His Son to be the propitiation for our sins. Beloved, if God so loved us, we also ought to love one another.

"No one has seen God at any time. If we love one another, God abides in us, and His love has been perfected in us. By this we know that we abide in Him, and He in us, because He has given us of His Spirit. And we have seen and testify that the Father has sent the Son as Savior of the world. Whoever confesses that Jesus is the Son of God, God abides in him, and he in God. And we have known and believed the love that God has for us. God is love, and he who abides in love abides in God, and God in him.

"Love has been perfected among us in this: that we may have boldness in the day of judgment; because as He is, so are we in this world. There is no fear in love; but perfect love casts out fear, because fear involves torment. But he who fears has not been made perfect in love. We love Him because He first loved us.

"If someone says, "I love God," and hates his brother, he is a liar; for he who does not love his brother whom he has seen, how can he love God whom he has not seen? And this commandment we have from Him: that he who loves God must love his brother also."

1 John 4:7-21

How difficult it is to love! How easy it is to know we have to do it, to say it. But it is next to impossible to do it. John gives a good reminder that inspires and defines for us what life we should be living. If we chase after anything, it should be love. For God is love. This is the contemplation on the eve of 2009.

Merry Christmas and a Happy New Year.

Separation vs. Association

A key function of the brain is to first, process the fact that we are encountering different types of stimuli at every moment, and second, process the simultaneous fact that while there are these different types of stimuli, there are also many consistencies that reflect modifications of the same stimulus at a higher level of abstraction.

One way to evaluate what a cortical region may be doing with respect to this separation/association dichotomy may be to determine the number of neurons at the first level relative to the second level.

If the ratio of neurons at the first relative to second level is large, then the function of the second level is probably to associate. This is a many-to-few limitation. So various permutations and combinations at the first level are funneled into the reduced dimensionality of the second level. Therefore, some combinations are subsumed.

If the ratio of neurons from first to second levels is small, then there is the potential for expansion. The problem becomes a few-to-many scenario. The same combination at the first level may elicit several possible outcomes at the second level. There is information expansion.

...

Slicing up HM's brain

Watch HM's brain being documented, slice by slice.

Click here for live link. At the time of this posting, they are already at the occipital structures. So they may finish soon. Not sure what will happen to the link or the video once this entire process is done.

HM was a famous epileptic patient who had much of his medial temporal structures removed as a treatment for the epilepsy. The result of this operation rendered HM unable to form new long-term memories. This finding was instrumental in the notion that the medial temporal structures, such as the hippocampus, is important for memory. Since his operation, HM has been heavily studied. HM passed away on the 8 Dec 2008 due to respiratory failure. [More about HM]

Developments after...

This has got to be the wettest year ever. The rains got so bad this year that snow aphids snowed down on our small little town of Champaign. Winter rears its cold face around the corner now.

The reason why I am posting this now, is because I have just returned from a series of inspirational events. Traveling north and south between Champaign and Dallas takes its toll at times. You get up early at 6am, clean up, and get on the 7.30am flight (2 hrs). Reach DFW. Get onto the shuttle for the rental car mall of the airport (takes 15min). Get the car, drive to the Dallas lab (20min). Work. Check-in to Embassy Suites (which is an awesome hotel!). And on trips back, leave the lab by 4pm. Return the rental car, take the shuttle to terminal B of DFW. Pass security. Have a beer and a burger at TGIF in the airport before getting on the 6.50pm flight back to Champaign, and be picked up by a familiar face.

Do this 20 times.

Recently though, work has been progressing. Papers are being submitted. Finally. And hopefully accepted! But I think the most inspiring event happened yesterday. Instead of going south, I headed north and gave talks at Northwestern. The data seems well received and everyone seems so interested and in agreement. I felt glad. It was worthwhile to drive up 3hrs and back 3hrs for that one day of wonderful meetings and interactions.

Now, the main concern are next steps. Where to go after this one year of post-doctoral research? Another post-doctoral position? Faculty? Tough decisions with too many factors that plague my mind, that give no clear direction. No amount of grad school prepares you for this! For life!

One can only dive in.

Agnostic Brain, Biased Mind - what does the FFA do?

Many neuroimaging studies have repeatedly found an area in the human brain that seems to be involved in processing visual faces. This area located in the fusiform gyri in humans, has been affectionately named the fusiform face area or FFA. The FFA is most active when we are looking at pictures of faces, and almost non-responsive to other types of visual items such as objects, houses, scenes, random textures, or a blank screen. Prosopagnosics, who are not able to recognize faces, but are still able to detect the presence of a face and also show no difficulty in processing other types of visual stimuli, have been shown to involve less FFA activity. Even more compelling, patients with lateral occipital lobes lesioned lose some form of object-processing, but show intact face processing. And yet other patients with lesions that have affected the FFA, have problems with face processing (acquired prosopagnosia) but intact processing for other stimuli. The evidence strongly suggests that there is something special about faces, and something about the FFA that deals with this specialization.

The debate regarding the FFA pertain to whether it is the only region or even a critical region that does face processing. Some labs have shown that face processing information can be found in other regions of the brain that are not the FFA. Yet some labs have shown that the FFA is recruited to process fine levels of category distinctions. For example, bird and car experts have been shown to engage some level of FFA activity when processing these stimuli compared to novices. These findings suggest that the FFA is not processing faces per se, but visual representations that have come to require high-levels of fine discrimination through experience, of which faces are the best example of this currently.

I suggest that a more flexible definition is called for when thinking about the FFA and its role in processing visual information. Certainly, it does seem that faces occupy a special place in human experiences. On the other hand, it is difficult to explain why there would be a brain region that codes for faces and faces along based simply based on genetic or biologically determined causes.

In terms of a neural network, if indeed the brain consists of many different sub-types of neural networks that conglomerate to form one large complex network, the FFA is a sub-network specialized to perform a specific operation that is maximized and specialized (trained) for a specific information domain - faces. This or these specific operation(s) could involve identification, discrimination, recognition, or all of these, or even a yet unknown operation. Certainly neural network non-linearities can surprise us! Moreover, these operations have been tuned for a specialized class of stimuli that consists of eyes, nose, mouths, and other visual characteristics of faces when occurring together as a whole (whether from external input, or through internal imagination or retrieval).

What this means is that if you were able to "remove" the FFA, and plug it into a computer so that you can feed this FFA network with inputs and measure its outputs, you could theoretically feed it anything, but the information would be most meaningful or organized when the inputs correspond to information about a face. Of course, this would require us to know what is the language of the input to perform such an experiment.

Other types of inputs may elicit some level of meaningful output of the FFA. Neural network do that. Yet other types may elicit nothing at all. This does not necessarily mean that the FFA outputs from such inputs is useless, nor does necessarily mean that it is used! It is just output. What higher-level brain mechanisms do with the output depends on the task, and how the brain is wired to treat outputs from its sub-networks. It may be ignored, or it may actually incorporate relevant information. That is, the FFA is agnostic to the incoming information. It does not care. It will process it anyway. But other regions decide whether what is it saying needs to be incorporated or not, or if it should be further modified even.

Such a view would reconcile why the FFA is special for faces, yet seems to be carrying some information about other stimuli. It would also be consistent with the idea that information about faces is certainly also available to a certain extent in non-FFA regions, the same principles being applied to these other sub-networks. It would also be consistent with how self-organizing behavior in neural network (see von der Malsburg article [link]) can lead to a consistent topology across every person that processes a particular stimulus in a particular way in a particular spatial location.

This is probably not a new idea, but needs to be clarified in the literature I think.

Cognitive abilities in kindergartners and first graders: A comparison, evaluation, and extension of models using data from Robinson et al. (1996)

Paper submitted for final in structural equation modeling class, Spring 2009, UIUC Psychology. This paper is a critique of Robinson et al.'s (1996) paper on "The structure of abilities in math-precocious young children: Gender similarities and differences", published in the Journal of Educational Psychology (Vol. 88, Iss. 2, p341-352). This current paper, though, focuses on the age differences in abilities of kindergartners and first graders.

It is known that very young children show less differentiated cognitive abilities. Children who perform well in tests such as those involving math, tend to have correlated performance in other tests such as in verbal tests. As children age and progress towards adolescence, however, their cognitive abilities becomes differentiated so that abilities such as math and verbal abilities are not necessarily equally developed in the child.

Presumably, this occurs because when children are very young, they are untrained and unaffected by external factors such as education and related experiences (e.g. streaming into majors). Thus, the best predictor of the child's performance is the individual difference or a general factor. With age, the child undergoes specialization where children start to develop more specific knowledge in selective domains. Some children become more trained at math, while others at language. Importantly, these abilities aren't always equally developed. This may be the underlying reason for differentiated abilities in older children.

This current paper is a methodological exploration of the data in Robinson et al. (1996) using various modifications of the basic structural equation model. The main results are consistent with differentiated abilities in first graders relative to kindergartners. Some discrepancies in Robinson et al.'s (1996) paper are noted as well.

[Download pdf of paper]

Default Network, Meditation, and Focus Training

A recent study found that teaching children to focus improves their health outcome [ScienceDaily report]. In relation to the default network in the brain, perhaps one of the things that such early training does is to improve the individual's ability to regulate default network activity. DN activity has been linked to self-reflection, self-monitoring, day-dreaming, task-unrelated thoughts etc., and has often been seen to be negatively correlated to one's ability to perform a task. That is, the more you are able to disengage your default network, the better you can perform the task. This is presumably because your attention is more focused and not distracted by task-unrelated thoughts.

It is then not hard to see the link between DN activity regulation and meditation. Meditation is an act of self-regulation of thoughts, and has been related to several positive outcomes, in terms of physical and mental health and ability. If we apply to adolescence and aging, perhaps one form of training that would be extremely deterministic of cognitive efficacy in older adults is the amount of focus training experienced.

Likewise, if we were to train indivduals on how to focus their mental thoughts, and improve them over time, might brain activity be modulated? And subsequently, might cognitive abilities be improved or preserved better with age?

My View on the Singapore River...Apparently!

Ha ha, forgot that I did this for Elaine long long time ago. Wow! Check out my interview.

http://www.fas.nus.edu.sg/geog/SingaporeRiver/vidz2.htm

Evolution of Hope

Hope in a few things,
Hope in nothing,
Hope in everything,
Hope in one thing.

The White Chapter

The White Chapter

Water in sight
Robbed of life
Sealed with unrelenting grip
Incapacitated by apathy
Unable to do anything
Unable to be

The color of dry
In stark sarcasm to its nature
Smirking at our hope for the future
Hope for a better world
How do we know?
For all that is seen
Is the wind
Blowing away the white powder
That was unable
Unable to cling to family

How To Make Teh Tarik

Teh Tarik, literally, pulled tea, is actually an Indian method of making milk tea. The milk tea containing condensed milk is poured from one container to another, which cools the tea down, and at the same time, introduces air bubbles. This gives it a lighter texture, and, as with most interactions between liquid consumables (such as wine) and air, brings out more flavor. Although, the average tea drinker will probably never notice the difference, watching the process of making this tea is a treat in itself.

The name Teh Tarik, is in fact a Malaysian word. Tarik means pull in Malay. This meshing of words and cultures is a result of exchange happening in the South East Asian regions because of the multi-cultural backgrounds present.

Presenting, how to make teh tarik...

Formosa Formosa!

Ok ok. It may seem like I very the free, traveling everywhere. But really, you have to see me in between. I is very the busy one. Only rare chance got time to go see see things, meet meet people. So must cherish the moment. Anyway, Taiwan. Shiokanadenmatology!

I got a free ticket because I claim mileage on Singapore Airlines. SQ hwaaa! Is good man. So much better than all the other airplanes. Acherly, I think any Asian airline is much better than any US airline. Ok back to the story...

Touchdown at Taipei airport and went to Bei Pu to have lei cha. This is where you use the stick and grind the tea leaves into powder. And eat muah chee. And grind and grind and grind until your chiu sng already. Then the tea become oily oily. Then ask the lady add water. Then and only then, can you drink your tea. Maybe is because you work so hard. The tea taste great. Then, after tea, we head to Changhua. Spend the night there, get pampered. Wake up to lots of fruits! Very healthy breakfast. And then, its off back to Taipei.


Went to eat xiao long bao at the original Ding Tai Feng with Zhimao. The bao is so juicy. I say, better than the Ding Tai Feng in Singapore. Very good. Can go again. There were a lot of people waiting in line. For some weird reason, they were mostly nihon-jin. Don't ask me why. So we eat eat eat. Then we walk walk around Taipei. Go to the 101 building. Their MRT exactly the same as Singapore one man! They also got the LOVE sign.

Then during dinner, we also meet Charlene's lab people to eat eat eat again at some Japanese teppanyaki style thing. Then we went to her small sister's place to spend the night. Next morning, we got up, went to get tau hway and Taiwan mian sian for breakfast and watched Transformers movie. Then its off to Hualien!

Hualien is beautiful. The place where mountains run into the ocean. The Pacific ocean to the east, the mountain ranges, Taroko Gorge to the west. Cliffs that hit the ground at ninety degrees. Water as blue as the sky. The sky as blue as the water. Rocks with lines and holes and rivers. All the color and texture coming together to make you feel that you are at home in the earth. We spent the night first at Bright Moon home stay in Hualien, which is a very cool and quaint place where you stay in a family like situation. We check out the ye shi there also. Eat and eat some more. The famous niu pai of course! And guan cai ban. And bbq sticks. I miss ye shis. And then we spent the next night at Taroko Gorge, Formosa Hotel.

Then we came back to Taipei and had dinner with the sisters at this cool yakiniku place. Very nice food and a fun time. Spent the night at Yuan Shan hotel (check out Ghost in the Shell, SAC 2nd Gig). Next day had niu rou main. Then fly fly away back to sg. Going back there again soon!
Check out the other pics [click here]

Nihon Nihon!

Some of you may or may not be aware (what kind of stupid statement is that anyway?), that I went to Japan for holiday. Shiokanaden! Subarashi! Hontoni hontoni! The food is good. The service is great. The people are gentle, and ...interesting. The sights and sounds are captivating. And did I mention the food is good? I never bluff.

The first day, we arrived at Narita. Took the Kensei line to Ueno, transferred to Ginza line to go to Asakusa. This took all about 2 hrs or so. But it was a pleasant ride. The most impressive thing about it was the train itself. Absolutely quiet! Acherly its going very fast lah. But then you don't feel it at all. How do they do it? Some weird nihon-o technology must be.

Then we arrived in Asakusa. This is where the Kamenarimon is. The Thunder Gate! Mon= men2 = door, by the way. We stayed at Ryokan Shigetsu. Very decent priced, very nice experience. Sleep on tatami floor and all that. There was also an onsen on the roof. I soaked in it. You are supposed to do it with other people naked. Separate for guys and gals lah, of course. Koki, a friend we met at a conference in New York, brought us around there with his girlfriend.

After Asakusa, we went to Hakone. Dai kirei da! This is near Fuji-san and lake Ashi. Take the romance car, the odakyu-sen, to Hakone-Yumoto. Then take a bus to Hakone-machi. We stayed at Ryokan Yugiriso. The whole package man! One night. Dinner and breakfast. Sushi lah, hot pot lah, pickled stuff lah, and a lot of other things dunno what it is. And of course, got onsen. Sleep on tatami. Can cry ah. Then after that, can see see the area. Very nice scenery in front of the lake. And also can go shopping at Hakone-Yumoto, very nice rustic charm.

Next is back to Tokyo, Shinjuku. We toured Akihabara where there weird people acting out anime and singing on the streets. We also met Niwako who brought us around the Meiji Shrine and also dinner at a sushi place in Shinjuku station. I tell you, so many cool things...can die already.

I took so long to put all these down because it seems that words cannot describe lor. Anyway, next time coming again. Check out the pictures [click here].

Goose or Noose?

This is a simple way of collecting data. Please indicate whether you think the two birds below are from the same species or no. Please also indicate your ethnicity and which country you come from.

Use the following template:
Answer: Same / Not the same
Ethnic Group:
Country:
1st Language:
Age of Acquisition:
2nd Language:
Age of Acquisition:

Neurotree

This is a cool website that tracks who was taught by who, and through it, you could trace how ideas get formulated and how they evolve...or not!!!

My Neurotree

HBM Conference 2007 Chicago

Went to Human Brain Mapping Conference last week. Stayed at Sheraton Hotel. We ate at several places during that time, so hungry...because always using brain, so all the sugar used up. But it was fun. First night we arrived, there were fireworks and the Blues Fest was on in Grant Park. Anyway, no photos because too busy working. Check out what was cool at the conference [click here].

Here are the eatery reviews:
Happy Chef Chinatown
Always my standard place to eat...we had dim sum there, although usually for dinner, you can do a set meal for very cheap (works out usually to be ~$8), and it comes with free lobster or crab.

Oysy
Japanese sushi place. Not bad...but probably Sai Cafe is better but more expensive. Anyway, its one of those modern sushi places. There's two outlets, one on Grand, and one one Michigan. Average cost ~$20-$30, depending on what you order.

Dao Thai Restaurant
Good food and cheap prices (~$6). Has some pretty authentic Thai dishes, and the restaurant has nice Thai looking decor where you sit on floors with wells in them so that you are the same height as the table...get it?

Gino's East
Took a while to get our pizzas, but that's because they were making it fresh, as any good pizza should be. The pizza is pretty good. Nice and thick. We had a mix of supremo and vege. The sauce was not too sweet or rich, so its good. ~$15. Giordano's near the Water Tower still has my vote.

John Hancock, the Signature Room on 95th Floor
What would a trip to downtown Chicago be without a brunch at the Signature Room? $20. Best view with food combination. Menu changes. Brunch is from 11.30am to 2.30pm. This is the same view you get as when you go to the observatory, for which you must pay ~$15. So go do the math...

Andy's Jazz Pub
In my opinion, this is the heart of Chicago, and the most worthwhile place to hang out for good music. Don't come here to have deep conversation. Come here to listen to the depths of music. Cover $5-$20. Drinks are decent, not too wide ranged, but enough, serves dinner too. Historically, several notable musicians have jammed here. I like the way you can sit right in front of the band, and also the jam nights...informal, naughty, crazy, eclectic, and it all gets into your ears. Trumpets, guitars, drums, piano, bass, the whole shebang.

House of Blues
Significant venue where many musicians have performed including Louis Armstrong. Its a theatre set up inside. Cover is more expensive, concert based. You'll have to check online to get tickets in advance. Serves food. I think its worthwhile to visit once.

Red Fish
Cajun style. Food is pretty good. ~$20. They have a live band. Plays rock.

Some Tapas bar somewhere...