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.

Evolution of Hope

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

I Think That I Shall Never See, A Brain as Pretty as a Tree

What if, sunlight to a tree, is as information to the brain? A tree needs sunlight to survive, to produce food. In response to this basic need, the tree spends a lot of its effort to maximize its ability to obtain sunlight. It does this by forming more leaves, and by spreading those leaves out at widely as possible to cover as much area as possible. Pushing this idea even further, to the extent that the tree covers a portion of area, that is the amount of sunlight it can absorb. Sunlight falling on other areas will be lost to the tree (albeit there might be secondary or tertiary transfer of energy via light reflection, diffusion, and other means). One important parameter that would determine the success of sunlight absorption for a tree would then be leaf surface area. Specifically, greater surface area would increase sunlight absorption rate.

Now, we project this idea onto the brain, of course being well aware that the brain is much different from a tree, although, probably not very very different. The brain is in the business of representing information. Its very function is the processing and retaining of all the information fed into it from the moment of its development. It would be interesting to pursue when this onsets, but that is a digression for later. Nevertheless, the brain develops in tandem with its experience with information. Some of that information is hardwired, or genetic. Some of that information is nurtured, or environmentally experienced. The role of each neuron then, in cooperation with all the other neurons in the brain, is to keep EVERY SINGLE EXPERIENCE, whether internal or external.

Why does the brain want to do that? Well, that's the same as answering why does a tree want so much sunlight for? We can only provide partial understanding here, because this borders on the domain of philosophical and religious pursuits. Biologically, a tree seeks sunlight as part of its nutritional source for the purpose of ultimately creating more trees. That is about as far as we can describe based on observation. This is, in a way, a tautology. Because what we impose as the purpose of the tree, is in fact, what we see the tree already doing. Therefore, such an answer may not satisfy some, but it is a partial answer at the least. Turning back to the brain, again, only a partial answer is given. The brain seeks to contain as much information as possible, because that's what is already observed that it is doing, and perhaps, this information helps the organism to survive, and to produce more organisms of this kind.

More importantly here, we shall consider how does the brain perform this function of representing as much information as possible. The tree does it by increasing surface area exposed to the sunlight. The brain's equivalent would be to increase the number of neurons it has, the connections between these neurons, the variability in the way these neurons can activate. Some smart person might be able to come up with an equation that tells us how much information a given brain with a given number of neurons and connections, and variability in activity, can hold. This could somehow be mathematically related to the concept of surface area...

However, there is a problem in terms of space. While the brain is fantastic and has way superior computational capacity, it is still finite. That is, there may come a time when a given person's brain can no longer process anymore new information. Maybe it has come already, just that we don't know it or that its not as big of a problem as we might think, given we have external aids for our memory now, through things such as computers, books, paper, language, and symbols. This finite capacity is indeed a problem, but our brains have a rather interesting way of solving it, at least to a great extent. Lets turn back to the tree for a moment, because its a greener thought. Lets say that to get more sunlight, the tree has two ways of doing it given a fixed amount of material. It can send more branches out with many leaves, or it can make fewer but bigger leaves. If it sends out more branches, it would have to content with using some of that material to make tree-parts that don't absorb sunlight (branches). If it makes bigger leaves, it may have to content with those leaves blocking each other out, since they will be close together as there are no branches to help spread them out. In the same way, the brain might have two ways of holding information within a limited amount of material. It can create more and more connections with more neurons, or it can use the existing neurons and connections in different ways. Here is where the tree analogy might break down. Unlike information, sunlight to a tree is a one-dimensional problem in the sense that it only needs to worry about expose area. Information, however, is obviously multi-dimensional, with auditory, visual, tactile, odor, taste modalities in the sensory domains, and countless of types of dimensions when you think about concepts and their associations, temporal information etc. Another dissimilarity between a tree and the brain is that most trees only make one kind of leaf, or grow with a certain fixed physical structure. The brain is able to flexibly use neuronal connections to group neurons in very dynamic ways. So, while a tree either has small or big leaves, the brain may use both small groups of neurons encoding some type of information, as well as bigger groups encoding other types of information.

The maximum surface area of the brain (meaning the physical ability of the brain to differentiate between its billions of states of activity using its neuronal connections), limits the total amount of different information the that brain can keep. This will be developed in later blogs. Here are some teasers. One brilliant way of reducing the space needed would be to encode information in terms of similarities and differences. And also, unlike a tree, the brain in the organism makes decisions about what the organism should do, affecting the environment and modifying subsequent experiences, as opposed to being completely at the mercy of the experiences.

Next time...."Similarities and Differences", and "The Brain, The Tree, Intentions, and Decisions".

Models that Account for the Same Data: The God Account

In reference to my post about models that account for the same data, one possible explanation for why there are so many religions is because of the principal component function in our minds (refer to the post). Here, we have the same data. But we refer to different dimensions to explain the data. Sometimes even omitting certain dimensions. Such omissions would lead to certain biases in explaining the data. And to the extent that the bias is critical (that is, to the extent that these biases are necessary for accounting for the truth), our explanation of the data will be off from reality. To the extent that the biases are not critical, we will not be off from reality.

The most accurate model therefore, is the one that most closely matches reality. Yet how are we to know reality? This is the problem of knowledge. Can we truly ever know anything since we are limited to our senses, five in all, and perhaps a little more. We have 5 dimensional information, and perhaps a little more. What if the data were more multi-dimensioned than our senses can experience? Even if we had secondary ways of measuring data from dimensions beyond our perception, our experience is still bounded by our perceptions. Thus, it appears that to ascertain reality, we need to transcend our 5 senses. But even then, how many senses or dimensions should we transcend? In theory, infinite. Which is of course, flatly impossible.

Therefore, the question is not about empirical proof anymore. We realize empiricism, limited to 5 senses, cannot ascertain reality. Really, all empiricism does is to come up with models to account for data within the 5 senses. Which has no consequence on reality itself.

We are back to the question: How can we know what reality is?

Why did Jesus Christ have to die?

There are many aspects to this question, but I would first deal with the most direct one and leave the rest for later comments and feedback.

Christ died because of our sin. Therefore, first we have to know what sin is. Sin is not just doing "bad" things like stealing, lying, or even killing. The core of sin is not knowing God as God. We all have sinned in that we all are born into this world not immediately knowing who God is, and not immediately acknowledging Him. All of us, at one point in our lives, were separate from God. This is a result of the original sin from Adam. But the sin also lies on us as well.

The result of our sin, is our death. Not just physical death, but death as separation. That is, once we are separated from God, we remain always separated. The problem is that God does not have sin, and therefore there is separation. On the other hand, God does not think that this separation is totally good. It is better for us to be with Him. So He worked out a way for us to be with Him again, even though we have sinned. The answer is Jesus.

Jesus Christ is God. Although He is God, He took on our sin, and died. This at once forms a bridge. It is both shocking as well as beautiful all at once, because God who cannot even have a hint of sin, took on our sin. And God, in whom is life itself, died. This might sound impossible, or ridiculous, or contradictory at first. But consider that there is a lot about God we don't fully understand. Furthermore, what is impossible to man, is possible to God. To live and die at the same time, to be pure but tainted at the same time. This is a radical concept, that perhaps we can slightly identify with in the form of our own emotions. How we can feel so completely elated but hollow, sad and happy, worried but at peace, angry yet in love, hate but respectful. How we can be many persons yet the same person at one time. Is it any more impossible for God to have this characteristic too but in infinite terms?

In any case, once Christ died, we see that the separation is made null, because God crossed over to our side, and in doing so, brought us back to Him. There is identification and acknowledgment. There is also a form of payment, as it were. A ransom for the price of sin. Sin meant death for us, but in our stead, Christ died. Ironically, it is Christ/God that defined that sin means death. So in essence, He was both fulfilling His own law as well as abolishing Himself and His law.

The story doesn't end there of course, because Christ also rose again from the dead.

Is it really about Ones and Zeros?

After all the arguments, the thinking, the theorizing, it probably only comes down to this: its either a 1 or a 0. The question is no longer whether its a 1 or 0, really. It has to be either one or the other, there is no middle ground. There is no 0.5. Because that would still be a 1. So, the real question, I think, should be: Who decides whether it is a 1 or a 0? Do we decide? Or does something else decides it?

After all our reasoning, we come to this point. Who is in charge? Us or Something Else? If we are in charge, can we be saved? Do we need to be saved? How can we be sure we don't? Can we ever save ourselves? Or in the end, do we realize that only Something Else can save us? In that case, are we really still in charge? Should we still live as if we are?

Impetus

Many of my friends blog. For some, it is a serious communication. A channel through which they can exchange ideas. Ideas that mean something to them. For some, it is just something to do. And yet again, for some others, it is a little bit of both. Because of this mish mash of people uploading information for various reasons, I find myself staring at one blaring and inescapable fact. Blogging is dangerous. Despite this, I decide to now contribute to the infobahn by wielding this double-edged sword. Why? Because even more dangerous, is that the Forgiven say nothing. We are on earth, let our words be few. And when we do speak, let our words change the world.