Autism and Phenotypic Plasticity

Recent research has underscored the large environmental influences in autism. These studies have reconfirmed that autism is not only driven by genetics but can be strongly associated with particular environmental situations. I have long had a hunch that autism may be linked with specific environmental cues that are predictive of the quality of the social environment that the fetus can expect to be born into. Research in the field of phenotypic plasticity and epigenetics has shown that many organisms, from plants to flies to people demonstrate predictive adaptive responses to particular environmental stressors. Environmental cues encountered early in life are used by the developing organism to fine-tune its body type, above and beyond what its genes have in store for it.

My intuition tells me that many social mammals may be receptive to certain foreboding environmental cues that give them information about the social environment that they can expect after birth. It is already known that rats and humans respond in a similar way to cues about stress. Researchers like Michael Meaney at McGill University have documented that stress responsiveness can be largely programmed in young rats. The frequency of early cues indicative of maternal care (such as the extent of early maternal stress, arched back nursing, licking and grooming) modulate the expression of genes that regulate behavioral and neuroendocrine responses to stressors. In other words, the bodies of young mammals genetically modify themselves to ensure that they are better prepared for a threatening environment.

I imagine that there may be similar cues that hold predictive value about the social environment. These have not been found, but this is probably because they have never been looked for. Or have they? It is known that maternal stress, serotonin levels, multiparity and others are risk factors for autism. Could these factors, or some facet of them, offer information to the fetus about the social environment? Are there other cues that the fetus could intercept and respond to that indicate how valuable social cognition has proven to be to their parents?

Take a look at the section on "autism and epigenetic programming" in my article on autism at:  http://www.solitaryforager.com/.

Set It Up So Someone Else Can Knock It Down

I just overheard a short, fun repartee between a disc jockey and a contest winner, and I learned a good lesson from it.

Disc Jockey: For the concert tickets, how sure are you that you just gave the correct and winning answer?

Caller: I am so sure, I can even put my hands up in the air and stay “Sure.”

Disc Jockey: Wait a minute was that a reference to a '90s deodorant commercial?

Caller: Sure was. I am so excited right now that I am sweating bullets.

Disc Jockey: Oh, but given how "Sure" you are the sweating is no problem for you right?

I really enjoyed this banter. The woman who was the caller made a joke, and then made a related comment setting up a punch line for the disc jockey to knock down. In the past I have always been focused on setting up my own punch lines. Not anymore though, I really liked this tactic and hope that I have the aptitude to set up these kind of exchanges for my friends.

Could Neural Oscillations Correspond to the Cycling of Imagery Between Sensory and Association Areas?

Brain waves are regularly occurring front-to-back cycles of propagating energy, as this graphic depicts. (Credit, Nature Magazine).

Since the 1930s, scientists have known that the brain has fluctuating fields of electric current that cycle back and forth from one area of the brain to another. These fields cycle very fast, several times per second in fact. The location and the speed of cycling, which is measured in hertz (cycles per second), tells us what kind of mental state one is in from intense thought (30+ hz.) to listlessness (around 10 hz.) to sleep (4 hz. and lower). These cycles can be measured by electroencephalography where electrodes placed on the scalp can measure variations in local activity. I think that these cycles may actually correspond to cycles of cortical activation between bottom-up sensory areas and top-down association areas. In other words, these brain waves are created by the process of throwing perceptions forwards and interpretations of those perceptions backward. Perhaps the back and forth reciprocations between bottom-up and top-down cognition map directly on to neural oscillations.

When you first open your eyes and see a new scene, bottom-up visual areas piece together the visual elements in front of you to create an image of the present scenery. But these early areas don’t know what the objects in front of you are or what to do with them they only piece together a picture of them. These early visual processing areas send the image on to higher association areas “downstream” that combine the knowledge about the existence of the objects with other concerns normally related with these types of objects and then send this message back to the bottom-up areas. The message that is sent backwards will subtly influence how you perceive your surroundings and how you understand them. Our whole world is pieced together from this back and forth cross talk. The early bottom-up areas, to some degree, wait for a split second after sending off their report about what they have perceived. This delay allows the top-down areas a little bit of time to process what it was sent and to send it back. Then the top-down area waits its turn, again for a split second. If this waiting didn’t occur to some degree, and if these brain areas just sent randomly timed messages, then the backward to forward cycling could not be measured with electrodes. Also, perhaps adjacent brain areas have to give each other time to finish their modularized processing. For instance, after association areas hand down information to early visual cortex (V1), the visual cortex needs a little time to use these specifications to create imagery which it will then relay back to the association cortices.

Maybe all of these bottom-up to top-down reciprocations are organized into very precise oscillations that propagate in regularly timed intervals across the brain so that they do not interfere with each other. The oscillations reciprocate back and forth at just the right speed so that each area has the time to process its inputs and send an output before the next complement of inputs arrive. Perhaps, messaging would be muddled if areas were to get information while they are processing, or if they didn’t receive all of their inputs at the same time. I wonder if it is possible to determine empirically if these bottom-up to top-down cycles of imagery map on neatly to the synchronized oscillations of neural populations known to give rise to macroscopic oscillatory electric fields, which can be observed in the electroencephalogram. I used to imagine that these oscillations traveled from the very front of the brain to the very back, giving all areas a chance to add their two cents to the imagery that was being created. Many of these reciprocating fields are much more localized though, and it will be interesting to understand how they interact with each other and spread in the brain. Also, there is not enough time for the brain to send information across the entire cortex 40 times every second (a common cycling frequency in the brain during heavy concentration and “cross-modal” processing).

Could it possibly be the case that when our brain is oscillating in the range of 30 hz, we are creating and then analyzing 30 mental images per second? I try to ask myself: “can you see images flitting back and forth several times per second?” It is probably impossible to perceive this “fabric” of thought because the mental act of noticing this and being aware of it would itself necessitate a number of oscillations. If true, this would mean that we are always experiencing life at these oscillatory intervals but we cannot notice it because it takes multiple intervals to notice and analyze a single interval. At any rate, it will take years of further research to determine if brain waves map directly onto patterns of bottom-up to top-down processing.


Read the full article that I wrote on this topic here:

http://www.sciencedirect.com/science/article/pii/S0031938416308289

Limitless: How can we unlock the full potential of the brain?

The trailer for the movie "Limitless" depicts a young writer who starts taking a drug that his drug dealer tells him will unlock the other 80% of his brain. The character, portrayed by Bradley Cooper, becomes fantastically intelligent and quickly wealthy and famous. Could this happen? Not so sure. A number of smart drugs, memory enhancers and “nootropic” supplements have been shown to slightly improve memory, motivation, attention and concentration. Vitamins B and C, folate, Omega-3, Ginkgo biloba, other herbals and proprietary blends of these like “Focus Factor” seem to help cognitive function. Central nervous system stimulants like caffeine, Adderall and Ritalin are more powerful, and have proven effects on mental ability, but it is not completely clear how any of these increase mental through-put. Some increase the effects of certain neurochemicals, some dilate blood vessels, some stimulate nerve growth, and most cause neurons to work harder. Simply put, most neurotropic drugs give the brain more energy to power its searches for appropriate memories. Does this mean that the brain is being used more, or that more of the brain is being used?

Is it true that humans only use 20% of their brain? No one can be sure because there is actually no way of knowing quite what this statement is trying to say. It is clearly not true that large portions of our cortex remain unused. If you watch the video results of an fMRI scan you will see that as a person does various tasks and is exposed to various stimuli, virtually the entire cortical surface will light up at one time or another. It is true that at any one time, only a small fraction of the neurons in the brain are being used maximally. But this is a good thing because the unused neurons would insert inappropriate and superfluous content that would be distracting and would take away from the specificity of thought.

It is helpful that we only use a limited percentage of our brains at a time. The brain has dozens of dedicated processing areas, each fine-tuned to solve particular problems, most of which would be irrelevant to a specific task at hand. In fact, much of the brain is designed around quieting or inhibiting extraneous stimuli so that only the most pertinent things can make it into consciousness. Your mind is able to do its work without distractions because your brain is constantly suppressing activation in areas that may seem to hold pertinent memories, but have proven in the past to be misleading. Arguing that we would be better off using 100% of our brain is like arguing that it is better to use each of the tools in a Swiss Army knife, at the same time, for the same project, all at once.

Brain researchers like Karl Lashley, in the 1950s were confused by certain experimental results and were falsely led to assume that the entire cortex of the brain was undifferentiated and that individual areas do not specialized in specific tasks or activities. Outdated principles, such as “mass action” and “equipotentiality” conceptualized the cortex as a homogenous pool of neurons where function could not be localized. Lashley and other neuroscientists of his day saw the individual tools of the brain's Swiss Army knife as interchangeable and able to be summed together. These conceptualizations were wrong but probably contributed greatly to the 10% myth.  In fact, it would follow logically from his principles that if specific brain areas do not have particular jobs and if we only use a small minority of brain cells at any time, that we could increase mental ability simply by increasing the number of active areas. Too bad it isn't that easy.

Activating inappropriate memories will not increase intelligence, but how about increasing the span of activity of the most relevant memories? As we think, we hold and let go of certain memories. If we could increase the time that certain helpful memories are activated and available to working memory then this, I believe, would increase intelligence. The brain area to target in order to do this would be the prefrontal cortex. I think that the movie Limitless, does an amazing job of portraying the effects of prolonged prefrontal activation or “hyperfrontality.”

The best kind of neurotropic drug that I can imagine would increase activity in the lateral prefrontal cortex. This would make it so that one was able to drag even more of their visual and verbal imagery with them through time. The PFC is like a switchboard with contacts in all kinds of other brain areas. The harder the PFC works, the longer various representations and subroutines can be maintained. In some senses, this WOULD allow someone to use more of their brain. Using time and mental resources to recall deactivated memories is like trying to use your fingernails to pry out the implements of a Swiss Army knife. Increasing PFC activity though, would be akin to having the most recently used tools in the knife unsheathed and ready for implementation.

Stress Primes You for Negative Thinking

I watched a great animated movie last night, "All Star: Superman." In it, Lois Lane visits Superman at his fortress of solitude for the first time but disappointingly she starts acting bizarre. She becomes highly nervous and begins to assume that Superman brought her there to experiment on her. After planning frantically to defend herself, she grabs a kryptonite laser from his arsenal and blasts him with it.

It turns out that she was exposed to some chemicals that increased activity in her amygdala. At that point, it all made sense to me. Even though Lois Lane is kind and thoughtful, she has the potential to become paranoid when severely stressed. She didn't have a good reason to suspect Superman of foul play, but when our amygdala is activated, we often trust it unquestioningly. We do this because it is so often right. The amygdala has a mind of its own. It unconsciously listens to many other brain areas and takes cues from the environment about when to be scared. We accept its messages as a type of foreboading intuition.

When activity in the amygdala increases, and the adrenal glands begin to release adrenaline and cortisol, the brain becomes primed for negative thinking. It is like your brain is retuned to perceive things as troublesome or upsetting. This is the opposite of a manic episode where someone with mania might perceive everything as a happy, lucky coincidence. A friend of mine who has experienced mania told me that for two days it felt like all of the cars of the freeway moved to let him through, like everyone was agreeable and like everything was going his way. When I start to feel that everything is going poorly I try to remember this - that neurochemicals can paint over reality.

I have noticed recently, that if one thing stresses me out, I am much more likely to get stressed out about other, completely unrelated things. I might get upset about an unfortunate circumstance and then wear cynical glasses for a full hour afterwards. One could say that this "displaced" negative thinking is not logical. It may be evolutionarily logical to be prepared for the worst during bad times, but from a modern, practical perspective it is illogical to generalize anxiety to whatever your mind turns to.

Remember, cortisol is high in the morning, so don't give morning stressors the attention that they feel they should be given. Also, remember Lois Lane, and make sure that one unfortunate circumstance doesn't lead to a domino effect of paranoia. Nowadays, I try to notice when I carry negativity over, from one thought to another. When I can notice it I try to tell myself that the negativity may feel valid and intense but it is probably just residual and misattributed emotion.