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.

Wicked Witch of the West steps on Scarecrow Brains with Magic Red Shoes

Charlene and I made this for Qinwei's birthday. We spent a whole week modifying things and planning what we could do to fit the Wizard of Oz theme. This is the result.

Ingredients

Green peppers

Red peppers

Bean sprouts

Rice

Can of corn

Carrots

Squash

Method

Cook the rice. Set it aside when done. First dice up the carrots and squash into small cubes. Make sure the corn is drained and dry. Pre-heat over to 350F. Start frying the carrots and squash in some oil. When they are almost done, add the corn and fry the mix for a few more minutes. Add the rice and mix the ingredients well under high heat. Add salt and pepper to taste. When done, cut the top off the green peppers, remove the seeds, and scoop the fried rice into the green peppers, making sure that they are compact. Coat the peppers with a little oil. Place the stuff green peppers into the oven, you can also bake the red pepper as well, it should take around 15-20 min. While the peppers are baking, stir fry the bean sprouts adding salt and pepper to taste. When the bean sprouts are done, lay them on the plate. Take the peppers out of the oven when done. Cut the red peppers into strips so that you can form little "shoes". Arrange them on the plate of bean sprouts, and place the whole green peppers on top of the red pepper shoes. Done! Wicked Witch of the West steps on Scarecrow Brains with her Magic Red Shoes.

3T Trio finds a new home in Beckman Institute

The Siemens 3T Trio is a full body MRI scanner. The Beckman Institute just recently acquired it. Today, the machine was brought to the basement of the Beckman building and we were fortunate enough to have some free time to glimpsed part of the process.

The scanner was brought in through a hole they have in the back of the building. It had rained the night before, so the ground around the hole was a little soggy. More importantly, they had to move fast because more rain was coming. The movers had to remove the heavy covers on the hole, lift the magnet bore and lower it into the basement, where there is a trolley for them to push the magnet into its final place. The movers took a break halfway because the rain did come anyway, before they could finish, but they continued later. As far as I know, the scanner is in the basement now, just waiting to be tested and used!

This is a full-body scanner, compared to the head-only scanner 3T Allegra. It should provide more uniform signal, although the 3T Allegra is sometimes better for certain sequences, or so I hear. So we'll see which one shines. They will move the 3T Allegra, head-only scanner, which is right now at the BIC down south, up into the Beckman basement as well, once this Trio is fully functional. There will still be about a month or so of testing and installation before we can begin to use it.

If you are my Facebook friend, you can check out other photos I have of this there [Facebook photo link].

An evening at Harvest Moon Drive-In

We went again to Bayern Stube, the German restaurant at Gibson City, just 40 min away from Champaign by car. This was to celebrate Sylvia's completion of her defense and graduating! Bayern Stube sells great beer and sausages, not to mention awesome desserts. Creme brule there is a must.

After dinner, we watched Year One at the nearby Harvest Moon Drive-In theater. Back in the good old days in Singapore, we used to have one drive-in theater at Jurong. This was taken over my mediacorp and turned into some place for housing film sets.

Harvest Moon Drive-In as two screens, and the thrill is not so much the movie, as it is the feel of sitting out under the stars, watching a screen, straining your ears to hear the dialogue from other peoples' car radios (you don't turn on your own because you are afraid the car battery will die out). And have that venture thwarted because the local train rolls by, chugging along on the metal tracks just behind the screen. The mosquitoes make a full meal out of you. Some people bring their sofas out behind the back of their trucks, some people bring their bbq. As the sun sets, the sky is glorious. All these make the movie a wonderful experience, no matter what the movie is about!

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]

VSS Conference Day 4: Demo Night Exhibit

VSS Conference Day 4: Demo Night Dinner

VSS Conference Day 4: Beach Day

VSS Conference Day 4: My Poster

This poster was presented at VSS Conference 2009 [link to VSS website], morning session [download poster pdf]. This study investigated the effect of task instructions on repetition suppression in the brain. Repetition suppression refers to the phenomenon that the brain response to repeated stimuli is usually reduced or attenuated. It is thought that such reduction in brain response reflects less neuronal recruitment, and hence, a more "efficient" way of processing the same information.
In this study, however, I postulated that under certain circumstances, the brain requires more neuronal recruitment in order to effectively process information for task demands. That is, repetition suppression becomes inefficient because it reduces the degrees of freedom that the brain can use to manipulate existing representations.

The study evaluated brain response in the fusiform region to face-pairs morphed at different levels of similarity. The idea is that the more similar face-pairs are, the more repetition suppression should be observed in the fusiform face area. Participants viewed the face-pairs under two different task instructions. The first task made face-pair similarity irrelevant. In this task, repetition suppression was observed to repeated faces. In the second task, face-pairs were made critical as participants had to make same-different judgments about the pairs. In this task, repetition suppression was eliminated.

The idea here is that in the same-different judgment task, the brain has to represent faces as distinctinctively as possible so that subtle morph differences can be detected. Thus, repetition suppression is prevented, possibly from executive function areas that process task instruction and exert a top-down modulatory control in the fusiform area.

The study also shows that there are individual differences in participants ability to exert this top-down modulation to regulate repetition suppression in the fusiform regions. This study was also performed in older adults, which will be reported in a subsequent research article. Briefly though, it is thought that older adults show declines in behavioral performance because of less distinctiveness in cognitive representations. This design is thus useful as a means to measure and related distinctinveness of representations in the brain and how that affects behavior.

VSS Conference Day 3: Illusion Night

Start of Illusion Night! This is an annual event where conference attendees submit their visual illusions for competition to see who's is the best. The top 10 are selected and show their exhibit here at Illusion Night. You can check out the illusions online [link]. The one that really wowed me was the curveball illusion, its the most dramatic one!

VSS Conference Day 3: Club car to beach

VSS Conference Day 3: Walking to the conference hotel

VSS Conference Day 2: Naples Grande

Touring the hotel lobby grounds.

VSS Conference Day 2: Poster session

Check out the poster session.

VSS Conference Day 1: Arriving at Fort Myers Airport

Just arrived at Fort Myer's airport, Florida. It is 80F and humid. Nice. The airport is about 30 min away from Naples. The shuttle will bring us there. More as we go along in the conference.

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?

A structural model of aging, brain and behavior

Possible working structural model that can be tested with measures of stimulus, behavior, neuro-functional, neuro-anatomical variables. The dynamic influences of age and "culture" can also be tested. Culture here refers to long-term experiences of any kind. More complex models can be postulated from this current framework by adding more factors, or measures, and by also constraining the specific weights and covariances. In the broadest sense, the weights and covariances are modeled linearly. However, certainly, non-linear functions can be imposed. The result of such impositions would be a neural network with non-linear activation functions.

Saltimbocca Chicken

Found this recipe while we were watching America's Test Kitchen. So you can look it up there also. I've modified it a little here. This is good. Saltimbocca means "jumps in your mouth" and this really does! Strictly speaking, the chicken is the saltimbocca, the pasta is from another recipe. I'll start with the pasta, because its relatively simpler.

Simple Creamy Pasta
Ingredients
Pasta (spaghetti, or any other type, string noodles are probably best)
Mascapone cheese
Two eggs
Salt & pepper
Any kind of suitable additional ingredients (we used mushrooms and asparagus here)

Instructions
Cook spaghetti in salted boiling water. Prepare sauce in the meantime. Use two egg yolks in a bowl, add two and half large "scoops" of mascapone cheese, stir until a smooth sauce, add salt and pepper to taste. Once spaghetti is done, mix into sauce, add chopped mushrooms and fresh asparagus, mix again, and done!

Saltimbocca Chicken
Ingredients
4 chicken breasts (thin fillet)
4 proscuitto (or ham) same size as chicken, or cut to same size
1 lemon
Parsley
Sage leaves
1/2 cup flour
Salt & pepper
1 1/2 cup white wine
4 table spoon butter.

Instructions
Preheat oven to 200F (this is for keeping the cooked chicken warm later when preparing the sauce). Make sure chicken and ham are dry. Add some pepper into flour. Coat the chicken with light layer of the flour. Sprinkle some chopped sage onto chicken. Place ham on chicken. Heat 2 tablespoon olive oil in pan. Fry some large sage leaves, few seconds each side, then set aside on oil draining paper for later garnishing. Place chicken in oil, ham side down. Leave for 4-5min. Turn chicken, cook for another 3-4min. Remove chicken and place in oven. Drain oil from pan, but leave the bits from cooking the chicken. Pour the white wine into hot pan and scrape the bits into the wine, let the wine reduce to 1/3 cup. Add half lemon juice, chopped parsley, and butter, stir mixture into a nice sauce. Take chicken out of oven, place on plate, put fried sage leaves on top, and pour sauce over and serve. Done!

Admiring a Predecessor's Work

In the course of writing my dissertation, I come across John Horn's work on Fluid & Crystallized Intelligence over the lifespan back in 1965. This is his thesis that he did while here at University of Illinois, and the copy is in our library. I borrowed it because in his work, he talks about how the factorial structure of psychometric intelligence changes with age.

The first thing I noticed about this work was that it was typewritten! Of course, it is not surprising, since back then, computers were not as available. Its not that. It was because I imagined the painstaking hours it took to generate this written document. What happens when you make a mistake on one single letter halfway? What happens if a fire burns the paper? Did someone digitize? I certainly hope so! How did he do all those calculations? It is extremely humbling to know that others have done this without the huge aid of modern technology and still produced such a marvelous product.

The next thing was that this thesis was signed by Cattell, well-known for formalizing this dual-factor theory of intelligence. Imagine, he touched this piece of paper. This is not sentimentality. This is reverence. I can only hope that my own work will one day be deemed useful to someone, even if only slightly. This is a perennial concern, beyond my control...but it is a strong hope. So much work has been done in the past, of which we mostly overlook or disrespect in our own ego to validate our own thoughts. We must recognize that "there is nothing new under the sun". But what has been given us is the joy of refreshing the old, and progressing into it in greater depths.

The final thing regards what Horn studied. Basically, he found that young adults perform better at tests of fluid intelligence than older adults, and older adults perform better than young adults on tests of crystallized intelligence. This is quite a well-known notion, of which I hear very little about these days. Perhaps it is my own ignorance? I am not sure, but reviewing this work sparks some need in me to investigate this further. Hence the impetus to pursue adolescent research to "fill" up the gap in lifespan studies in cognitive aging, which has focused on older adults. Perhaps much has already been done, I just haven't been in contact with this field or literature...time will tell. I will have to read up more. The graph in this photo is from his thesis. It is hand drawn, and it truly speaks a thousand words.

Studying Adolescents

The more I research into aging, the more I think that one important aspect of lifespan research is the adolescent period. This is an "impressionable" age, and there may be a good reason for that. Longitudinal neuroimaging data is needed to evaluate the impact of life experiences on determining subsequent aging outcome. Possible future pursuit?