Final Blog Entry

Given the immense amount of perceptual stimuli we receive at a given moment, it is critical that our brains make sense of what surrounds us. For people with Asperger Syndrome (AS), interacting with the perceptual world becomes a constant struggle, which we typically take for granted. AS falls under the category of autism spectrum disorders, which are childhood-onset neurodevelopmental disorders affecting key fronto-striatal and fronto-parietal circuits that are important for executive functions. [1] An executive function is a neurophysiological term used to describe mental functions with which higher life forms, such as the prefrontal cortex, govern their behavior. [2,3] Due to deficits in executive functions, those with AS experience altered sensory input and thus attach altered meanings to sensations, which may in turn give rise to the syndrome’s key symptoms. Classic symptoms include alexithemia (inability to talk about one’s emotions), intense fixations on an object or activity, precocious language, and extreme attention to detail. Often, these symptoms label AS individuals as loners or socially awkward, and as a result they suffer from depression and anxiety as they enter their teenage and adult years from social isolation. [4] Given the scant knowledge on how to treat the syndrome, the best way to ‘treat’ the symptoms is to use behavioral therapy to teach AS patients how to compensate for their altered forms of perception so that they can become functional, to a degree, in society. [5] Thus, it becomes necessary to understand how AS individuals perceive so that we, as a society, can teach them as well as ourselves how to interact in such a way that augments perceptual and social understanding. 

There are several clues present in AS cases that can help us understand how they see the world. AS individuals often display hyperacuity in one sense, while they display hypoacuity in other senses. The person is able to become hypersensitive to one channel of sensory input by relying on ‘monotropism,’ or one-track processing, to make sense of their surroundings.[6]  Normally, people are polytropic in order to synthesize multiple channels of stimuli to make a cohesive story of their environment. AS individuals, however, lack the executive functions to process multiple channels and thus concentrate all of their processing abilities on one channel. As a result, AS individuals perceive their environment holistically in one type of sensation, rather than selecting the relevant stimuli from the background noise coming from all sensations, which makes it extremely hard for AS individuals to sift through all the incoming sensory information. Commonly when asked to prioritize stimuli, AS individuals categorize normally irrelevant stimuli as very important. This explains why young children with AS are misdiagnosed with ADHD. [7] These children are trying to learn how to prioritize what is relevant in their environment, but their mono-channel processing does not allow them to pick up all the cues that should help them make sense of their environment. In particular, this monotropism may account for AS individuals’ ineptitude in social interactions, as they do not learn to pay attention to the normal emotional expressions or social cues. Often AS children are so transfixed on their own pedantic preoccupations (such as describing the circuitry of a computer), that they do not pay attention to other children’s boredom and are eventually ostracized by the other children because the other children do not know what to make of such discourse.

Another common feature of AS is that AS individuals are not fooled by psychological illusions, such as the chalice/face illusion. Rather they perceive these illusions for what they are; as in the case of the chalice/face illusion, an AS individual would perceive the chalice and face at the same time, placing the same amount of priority to the chalice as to the face. This is due to the fact that their brains do not filter what they are perceiving. In effect, AS individuals perceive the world as it really is- their brain does not stand in the way of misinterpreting the world. [8] And sometimes this can be an advantage, rather than a defect. For instance, AS artists can depict a scene with incredible detail by starting at any point of the scene. Normally, artists have to start at the focal point and then orient themselves to depict the scene from that focal point. Given that AS individuals perceive scenes holistically, they do not have to start at the focal point to accurately depict the scene. For them, there is no focal point, and each point of the scene earns as much relevance as any other point in the scene. As a result, AS individuals are incredibly good at depicting what really is there- their brains do not stand in the way of trying to create a false interpretation of the world.

To compensate for their monotropism, AS individuals have to relearn how to detect relevant stimuli from the environmental noise. According to Signal Detection Theory, an AS individual’s ‘present’ and ‘not present’ detection curves are practically overlapping, so they have to learn how to be extremely vigilant in order to detect the relevant stimuli. The methods used by AS individuals to compensate for signal detection are extremely variable, but AS individuals are also commonly known to be synesthetes. [8] They learn to make associations between two perceptions, typically between hearing and seeing, in order to make up for the lack of multiple-channel processing. This can become a problem, however, when AS children go to school and are bombarded with extraneous sensory information while trying to take in what the teacher is telling them. Therefore, it becomes crucial for the teacher to have the AS student’s utmost attention while he/she is learning in order to make sure the student is properly learning. However, given the present conditions in the classroom, it becomes near impossible for teachers to take on such a responsibility, and the student is left to become a classroom liability rather than an active participant.

Asperger Syndrome is a very hard neurodevelopmental defect to characterize, given the wide array of phenotypes that manifest in diagnosed AS patients, and so it is hard to pinpoint any sort of treatment. With emerging  neuroscience technology, it will become easier for scientists to begin looking at the biological aspects of AS. Society, on the other hand, has a long way to go to make room for any changes that will make it easier for the integration of individuals with Asperger Syndrome. But for now, the best thing we can do is to view those with Asperger Syndrome as individuals with an altered way of looking at the world rather than people with neurological defects.  

1. Hill, E.L: Evaluating the theory of executive disfunction in autism. Dev Rev 2004, 24: 189-233.

2. Middleton, F.A. and Strick, P.L.: Cerebellar projections to the prefrontal cortex of the primate. J Neurosci 2001, 21: 700-712.

3. Middleton, F.A. and Strick, P.L.: Basal-ganglia ‘projections’ to the prefrontal cortex of the primate. Cereb Cortex 2002, 12:926-35.

4. Delacato, C. The Ultimate Stranger: The Autistic Child. Noveto, CA: Academic Therapy Publications, (1974).

5. Frith, U. Emanual Miller Lecture: confusions and controversies about Asperger syndrome. J Child Psychol Psychiatry 2004, 45: 672-686.

6. Lawson, W. ‘Reflection on autism and communication: A personal account.’ Autism99 Internet Conference Papers, (1999). www.autism99.org  

7. Sinzig, J. et al. Inhibition, flexibility, working memory and planning in autism spectrum disorders with and without comorbid ADHD-symptoms. Child and Adolescent Psychiatry and Mental Health 2008, 2: 4-15.

8. Bogdashina, O. Sensory Perceptual Issues in Autism and Asperger Syndrome: Different Sensory Experiences, Different Perceptual Worlds. London: New York, electronic reproduction (2004).

 

The Dark Ages

Prior to 1100 A.D., painters did not convey several realistic aspects in their works that today many artists take for granted, such as proper depth perception, age, and detail attention. The limited understanding of linear perception restricted artists’ ability to create one of the most essential ideas of realism. Under the patronage of the Medici in the fifthteenth century, painters were able to study the Grecian forms of sculpture in Florence. The influence of classical artwork enabled artists to grasp the concept of perspective. However, it took about a hundred years for artists to accurately depict human form. Michalangelo   

A Heavenly Spectrum

In his Deus Absconditus, Martin Luther rejects the  continuity between religious understanding and perception. Philosophy was the ‘devil’s whore’ and the pursuit of God’s omnipresence degraded the true revelation of God’s words written in the Bible. Luther argued against the idea that God’s being could be infinite because there was no such thing as infinity. The concept of limitless boundaries went against Luther’s theology, which stated fides quarenes intellectum (faith seeking understanding) misguided Christians into asking questions that would lead them astray from revelation. I, however, believe that Martin Luther failed to calculate the importance of scientific understanding as a part of appreciating the world in which we live in, which would make learning to accept the ambiguities inherent in religion a more intellectual fulfillment.

Take, for instance, the number two. Most people would claim that the number two is absolute; two is a concrete description that enumerates a specific quantity. Yet, if you take into account string theory and mathematical principles, the number two is just an abstraction. Two may be helpful in counting objects as we perceive them, but theoretically speaking those two objects exist in an infinite number of dimensions. Nevertheless, the abstract idea of the number two is meaningful to us in a very physical way.  Although a loving couple might not be aware that their bodies exist in parallel universes, they are extremely aware that their love for one another is contingent on the fact that their two beings are attracted to each other.

Another similar example would be white light. Thanks to Isaac Newton’s prism experiments, we now know that white light consists of a spectrum of visible wavelengths.  Even though many people are aware that white light is a composition of different colors, the knowledge does not stop them from appreciating the simple beauty and importance of light. In fact, I would say that understanding light’s properties has enabled us to dig deeper into developing ways to explore the elegance of light. Think of all the ways in which our world uses the concept of transmitting wavelengths. From developing new art forms to preserving a brother’s first taekwondo tournament, understanding light and the way we perceive it has helped us uncover many mysteries of this world.

I would like to argue that Martin Luther and John Keat’s lament of scientific discovery discredits the human nature that thirsts for learning how to interact with this world in order to become more aware of what is really here. I do not think the pursuit of knowledge detracts from religion.  In fact, I think learning about nature and the interactions that take place in this universe has taught us to not take this world for granted and to appreciate what we have.   

Everyone is entitled to their own opinion, especially when it comes to religion. Personally, I believe that the sanctity of religion is derived from the experiences people face, where their perception of the world defines what is holy, God, or philosophically relevant. The state of holiness and understanding does not belong to objects or what most people would consider “real” or “absolute.” Rather, it comes from what our perception deems as relevant to finding a purpose in living.  

Where do we go from here?

The process of constructing the human nervous system along with the sensory organs is a long and dangerous journey full with many paths that could stray from proper development.  Starting out with the expression of bHLH (basic Helix-Loop-Helix) proteins during in embryogenesis, neurogenesis begins as neural stem cells differentiate into progenitor cells. As one protein up-regulates or down-regulates another protein, the cascade of reactions sets up the proper conditions for maturation of neural cells and at a certain critical point, synaptogenesis, arborogenesis, and myelination also begin.  These processes, however, continue after embryogenesis and have been shown to even occur in adult brains. During any point of brain development, the misregulation of transcription or translation could disrupt  normal neural patterns.

One bHLH protein, Pax6, is a cell marker in progenitor cells found in the lower neural tube during early neurogenesis. The deletion of the gene that codes for Pax6 leads to the Small Eye (sey) phenotype in mice and is known to disrupt proper eye morphogenesis (Osumi et al. 1997). The reason I include this example is that geneticists can manipulate the expression of the bHLH proteins with various chemical techniques.  Though such manipulations do not usually happen in utero, the age, diet, and exposure to neurotoxins of the mother may affect the subtle differentiations that lead to proper eye development of the fetus.  ”Twin studies of many neurological disorders, such as attention-deficit hyperactivity disorder, Parkinson’s disease (PD), and Alzheimer’s disease, show a low correlation between identical twins, suggesting that environmental factors may play a role” in cell fate mapping during neurogenesis (SFN Spring 2004). The cellular interactions that determine the differentiation pathways are a complex orchestration of molecules in the right place at the right time, and any disruption of the temporal or spatial orientations of the subcellular components also could disrupt the macroscopic outcome of proper neural development, including proper visual perception.  Therefore, the deprivation of normal stimuli or the presence of harmful stimuli in the environment of an embryo and a young baby could definitely alter their future visual perception. 

 

Osumi, N. et al. (1997). Pax-6 is involved in the specification of hindbrain motor neuron subtype. Development 26,  2961-2972.

Society for Neuroscience. (Spring 2004). Neuroscience is Research Priority for NIEHS. Neuroscience Quarterly. <http://www.sfn.org/index.cfm?pagename=neurosciencequarterly_04spring_niehs>

 

Achtung!

There is one nice thing about living on campus- I no longer have to worry about making it home safely in the hectic traffic of Dallas.  During my senior year of high school I worked as a research assistant at UT Southwestern, and it took at least 40 minutes to get home on a good day.  I had to go through some of the worst traffic intersections in the country, and I don’t know how many times I came incredibly close to having an accident.  It was not because I was preoccupied talking on the phone or getting something out of my purse.  I really thought I was paying attention to the traffic around me.  But somehow or another, the car in front of me always seemed to jump from 50 feet ahead of me to only 10 feet in just fractions of a second.  (Luckily, I have incredibly good breaks on my car.) 

Having learned about inattentional blindness and change blindness, I can see why that happened so frequently.  Often when you are driving, there are countless things to pay attention to.  Not only do you have to watch the car in front of you, you also have to watch out for the car that is signaling to switch into your lane and the countless road signs. In combination with the multitudes of distractions from billboards, buildings, and that sweet car you wish you had, driving in the city during rush hour is a petri dish for cultivating the optimal conditions for inattentional and change blindness.   

A Tribute to Andrew Bird and Vision

Light from any direction,

Hitting, hyperpolarizing a receptor

It has to be right on center,

Or else it doesn’t matter

(At least for a ganglion cell’s predilection.) 

 

 From upside down to across the midline,

Now a thousand pieces schismed.

Images crisscross the chiasm,

The LGN separates the movement and color prism.

Making it easier, putting the puzzle pieces in line. 

 

Fanning out across the optic radiation,

Keep it topographic all the way.

The striate cortex doesn’t give the periphery its fair say.

M, P, and K projections shouldn’t get mixed up in the fray. 

Gives rise to cortical magnification. 

 

Seeing you dance wouldn’t be right without orientation selectivity.

Take your pick: simple, complex, or even hypercomplex.

It may be Light’s contours that determine the reflex. 

I’ll give superiority to the oblique effects. 

Orientation constancy will keep you in line with gravity. 

 

Interdigitated stripes of layer four

  Abolishes our eyes’ segregation.  

Other layers give way to integration,

Where ocular dominance allows for simultaneous activation.

Orientation and direction have equal footing on the binocular cell’s floor. 

 

Color residing in a blob

Again, it all depends on the receptive field.

Color opponency forms a shield,

The fate of the response is not sealed

where layer four is the site of color-seeing’s job.   

 

From columns to the dual system, action is separated from seeing.

Location of objects flowing down the dorsal stream.

  I wonder how strange this picture may seem,

When lesions block the temporal stream.

Adaption evolved for our well-being.   

 

Vision is a collaboration.

Sifting, shifting, breaking apart

Aspects of light that I just took to heart,

Never paid any attention until I had to learn where to start.

Now I know why your image is my adoration.  

HD TV

If you are lucky enough to have and watch an HD TV, you probably have never given any serious thought to why the football game on the TV looks so good.  Sure, the change from analogue to digital signal has something to do with it, but that’s not the whole picture.  Engineers are constantly trying to create things that optimally stimulate our brains, whether those things be a TV, building, or heart monitor; so they not only have to understand the physics of the real world, but also how our brains perceive reality.  Thus, the creation of the HD TV is a marriage of digital logistics, calculus, and neuroscience. 

The most important idea in creating an HD TV is figuring out how to transmit digital information in bits that retain the most visual clarity when it is transferred to the TV screen.  Older analogue TVs sent signals every 50 msec that encoded the color for every pixel in the screen for every change of frame, but because the HD TV signal also encodes for intensity, movement, and color, HD TV cannot transmit information the same way. If it did, 50 GHz would be sent for every signal- that’s a lot of digital information! Therefore the signal is condensed and broken into what are called frames.  First, an i-frame is sent once every second.  An i-frame encodes for all the color and intensities that every pixel should display for the next second. Then, a b-frame is sent about 20 times a second that encodes for image movement by directing points of light in a series of vectors.  In coordination with b-frames, m-frames are sent to predict where images will go by the time the next i-frame is sent.  To illustrate what these frames do, imagine a white TV screen with a red dot in the middle, where the red dot is shrinking towards the center.  The i-frame tells the TV that there is a white screen because the white screen is constant until the next i-frame.  The b-frame tells that some of the pixels change to red, and that the movement follows certain trajectories toward the center. Finally, the m-frame predicts where the edges of the red circle will be by the next second. Though this example is extremely elementary, what you get with the division of information transmission through these frames are finely tuned edges that make depth perception on the screen much more defined that a regular analogue TV.  

But what really makes the image so clear is how are brain works in sync with the HD TV.  Visual acuity depends on edge detection, and thanks to the structure of the center-surround ganglion cells, our brain is able to ‘see’ the football going across the HD TV screen. In addition to eye structure, our brain is able to pick apart many aspects of light movement and depth perception in the visual cortex, which gives watching TV its appeal. Engineers spent countless hours trying to figure out just how our vision is maximally stimulated by certain projections of light, and what they came up with so far is the HD TV. Cisco and its associates that specialize in producing TV screens have done countless research hours on how our eyes perceive light. In one project, they looked at how different color intensity projections affect starring and blurring on the TV screen.  Blue light has to be shown at three hundred times the intensity as red light because it takes a much higher energy of the 420 nm wavelength to be perceived by the eye.  Therefore, when the different intensities are combined on the TV screen, a small percentage of people can detect blurring or starring effects on the screen. Cisco engineers has to understand what and how our eyes perceive in order to make sure that things like starring do not occur.  

Another thing engineers have to understand is how rapid our brains can fill in the empty spaces between frames.  The combinations of i-, b-, and m-frames  carefully manipulate our visual sense- images on the TV are not actually as clearly defined as you think they are.  Have you ever noticed how blurry the TV screen is whenever you pause a movie?  Our brain picks up the images’ movement and color on the TV screen and imagines boundaries that make our perception much clearer than reality (at least in regards to what’s happening on the TV screen.) As  our visual projections filter through the lateral geniculate nucleus, superior colliculus,  and optic radiation to the primary cortex, our brain constantly picks up apart all the individual aspects of movement, color, depth, and shape to integrate our visual experience with other aspects of our senses. On top of understanding what is already there, our visual perception fills in the gaps between frames with what our brain believes is happening.  The result is a fluid stream of visual output rather than a succession of visual frames, and because an HD TV separates color, from movement and shape, our brains are able to independently perceive color and movement more clearly, though we ‘see’ those two aspects as one indistinguishable unit of vision.  

Faces

When my parents came to pick me up from the airport, I was almost surprised to see them in person.  I have hardly been home since I began college, and I have become used to just hearing my family’s voices on the phone.  So when I saw their faces as they drove up, it reminded me just how long it’s been since I have had an extended stay at home; however, my surprise quickly melted away and I quickly adjusted to all their mannerisms.  The little expressions unique to my mom and dad that I have committed to heart weren’t so hard to remember, which is important when I live around them- It’s a bad idea to ask my mom to go to a friend’s house when she has that certain look, if you know what I mean. . . 

Besides navigating my mom’s volatile moods, emotional recognition is key in our daily interactions.  Helen Keller may have lamented her loss of hearing more, but not all of us have the privilege of discerning other’s facial features with our hands.  I don’t know too many people that will let me do the same thing Helen Keller did to President Eisenhower in the photograph.  Facial expressions are vital to communicating fear, excitement, caring, and other emotions that convey social needs and wants.  With the aid of our human vision, we can pick up the smallest changes of the facial muscles that belie our true feelings.  A small twitch of the brow can give away person trying to cover up a lie.  Known as a microexpression, this small facial movement (and many others) can be used as a good lie detector.  I watched a BBC program on neural processing of emotion recognition during the break, and it discussed an experiment on lie detection, that tested judges, lawyers, policemen, CIA agents, and other professionals that deal with lie detection on a daily basis.  Given their occupations, you would think they would be experts on picking up the faintest signs of a lie; however, only one group of professionals performed higher than chance level.  The CIA agents were able to accurately able to analyze lie detection 80% of the time. What made the agents so much better than anyone else at lie detection was their training in picking up microexpressions.  Normal facial expressions last about a second or two, but when people lie, their expressions become much more abbreviated- about 20 ms in duration. Agents are specially trained to recognize these quick changes in facial expressions for lie detection in interrogations, yet microexpression recognition is not rocket science.  Just by watching the BBC program I could pick up some of the microexpressions in some of the trials they showed.  And you could, too, if you watched the show.

So what makes us good at expression recognition?  Projections from the visual cortex to the amygdala synthesize our vision with an emotional context.  

Broadband Listening

Broadband technologies have revolutionized the way the world sends and views information.  With a click of a button, megabytes of visual and audio stimuli at our fingertips thanks to new developments in DSL, cable, and radio transmissions that implement broadband.   Broadband refers to the signaling method that uses a wide array of frequencies.  Much the same way as broadband is used, our ears pick up a relatively large range of frequencies and transmit them via the auditory nerve to a multitude of processing centers; and just like technology when it does not work, disruption of the auditory pathways can cause serious problems. Aphasias like Wernike’s aphasia and Broca’s aphasia as well as lesions in the cochlear nucleus show just how many processing areas there are in the brain that  give rise to our reality of speech.  Especially when you get into the binaural processing areas like the superior olive and inferior colliculus, activation of a particular neuron requires a specific type of sound.  For instance, neurons in the secondary auditory cortex only respond to rising sounds. The acoustic fovea also concentrates on the frequencies present in speech. Given the widespread area devoted to speech frequencies in the brain, speech is crucial for our daily interactions and has been for a long enough for evolution to select for our brain development. Human conveys so much about our emotions and our needs, and without it learning about our neighbors would become much harder.  Sight does influence our hearing, but it can also work the other way around. Just think about how much we depend on hearing to learn.  

Telephone

 

Did you ever play the game Telephone when you were a kid?  (You know, the game where you all sit in a circle and someone whispers into the next person’s ear until you have gone around the entire circle.)  The game would start with a phrase like “Is Brad starting to go out with Jen,” and would end with complete nonsense – something along the lines of “Is Brad sharking a go-out engine?” What made some words so hard to discern while others were easier to pick up? I am not completely sure, but I bet it has something to do with people’s different thresholds for various frequencies and intensities of sound.  Although the speaking range of frequencies is the optimal range for human ears to pick up, whispering certainly hinders the clarity of the speech.   Instead of the tonal quality that normal voice level produces, whispering has a lot of background noise that mixes in with normal speech.  This results in less distinct syllables and inflections that we cue into to listen.  The game Telephone takes away the familiar patterns of speech and then takes advantage of individual sound acuity level. Whereas some people are very good at telling the difference between sounds, others are not quite as gifted.  The discrepancy manifests itself in Telephone and the ending product is a bunch of mismatched words.