Wednesday, May 14, 2014
I have written a new blog post elaborating on the topic of my recent winning FameLab talk about aerobic exercise and it's effect on memory. The post is being hosted by the British Council, but it's very much in the spirit of The Science Stoop--humorous and informative. Check it out.
More original ScienceStoop posts will be coming this summer!
Sunday, June 23, 2013
It’s ok. You can admit it.
You’ve thought about moving stuff with your mind at least once in your life. If not recently, then definitely as a kid. You probably just watched X-men or Star Wars for the first time and thought about how cool it would be to make objects fly around just by thinking it. Unfortunately, as it is with all psychic fantasies, it probably ended with you staring at something for way too long with that classic telekinetic look of intense constipation.
Although we may have failed, a few scientists with some ingenious ideas and noble goals have started projects that are bringing us closer to that dream. Some of these projects are giving people the ability to control robot hands and other tools with their thoughts. But more importantly, this research is pushing the boundaries of what’s possible and increasing the quality of life for paraplegics.
The video below is a just a peak at some of the work in this field. It shows Matt, a quadriplegic patient, who is hooked up to a machine that allows him to use signals from his brain to control a robot hand.
As amazing as that is, this was just the early work that happened over seven years ago. More recently, a few research groups (including the one responsible the hand movement you just saw) have made some improvements to these neural prosthetics. Some of the new additions include the development of a full arm, the ability to make more life-like movements and lifting objects.
Cathy, a paraplegic patient who worked with the same research group was able to use signals from her brain to control the upgraded prosthetic and use it to drink coffee.
It’s seems unreal that someone outside of a movie screen can actually do this. So you might be wondering “How is this possible?”
It’s because scientists have taken advantage of the way our brain cells, called neurons, communicate. In our brains, there are groups of neurons with different jobs. When neurons responsible for body movement or motor neurons, “talk” to your body, they can make muscles move.
A big part of this neuronal communication is electrical. It seems weird to think that any part of you has electricity in it, but it’s true. Very tiny amounts of electricity are generated in individual neurons when they “talk”. Depending on which of your motor neurons is talking, along with how often they talk is how motor neurons decide what muscles move and how.
So just as lights on a marquee are arranged in a different pattern for every word spelled, the same is true for every body movement you make. There is a different combination of motor neurons talking that drive each of your movements. These combinations are known as patterns of motor neuron activity.
It’s these patterns of motor neuron activity in the patient’s brains that scientists are using to control the robot arms.
Unfortunately, unlike Jedi’s, X-Men and little girls named Matilda, if you wanted to use these patterns of motor neuron activity to directly control things other than your body, you’d run into a problem.
Although one pattern of motor neuron activity may make your arms flex and another pattern might get your legs to extend, these mean as much to a robot arm as you yelling gibberish at it with your mouth full. The many years involved in your development and all the experience of driving your movements have tuned these patterns of neuron talk into a special language that only your body really understands.
In order to let the neurons in your head talk to objects outside the body, there needs to be something to bridge the gap and teach the language of the motor neurons to the robot arm.
Understanding this issue scientists developed Brain-Machine Interfaces (BMIs), which act like the robot arm’s version of Google Translate™. It’s the job of BMIs to take the language of the motor neurons and in real time tell the robot arm what the patterns mean in a language it can understand. So when the robot arm receives the translation, it can perform the same motions from the same motor neuron activity that drives the person’s arm motions. These BMIs which seem so complicated and almost defy logic by allowing thought to control objects, are made up of two basic parts:
1) A Sensor. It’s something that can listen to what the neurons of the human or animal are saying. It’s usually composed of tiny metal electrodes that are literally plugged into the exposed brain. It can detect electrical changes in different areas where individual or groups of neurons live. This is connected to….
2) A Computer. The backbone of the operation. It’s used to record and analyze the neuron talk sent to it by the sensor. After analyzing it, it converts the information into a command that is congruent with the desired action. This information is used to drive the connected thing you’re trying to control. It can be a robot arm, a mouse cursor and sometimes even another animal.
One of the first scientists to use this technology to successfully assist people was Dr. John P. Donoghue. He and his team of researchers wanted to help Matt, a guy who a few years earlier was paralyzed from the neck down by a knife attack. By creating a BMI, which the researchers named BrainGate™, the Donoghue team was able to help Matt, Cathy and a few other paraplegics use their thoughts to command physical robot arms and digital mouse cursors to give them the ability to interact with the world around them.
They were able to do this because they had literally plugged sensors directly into Matt’s brain that could essentially read his mind. The sensors were in Matt’s motor cortex, which is the part of the brain where motor neurons live. The BMI was able to look at the different patterns of activity of Matt’s motor neurons when he imagined performing different tasks.
The researchers would put commands on a screen that Matt was supposed to imagine doing like ‘open your hand’. Matt being paralyzed couldn’t actually do these things, but his brain (because it was above the site of injury) could still respond just as if he had control of his body.
So Matt would focus and imagine trying to open his hand. The BMI then recorded the pattern of motor neuron activity that happened while he was imagining opening his hand.
Then they asked him to do this over. And over. And over. And over again.
They did this so many times that when they combined all of the ‘open hand’ patterns they collected, they were able to be really sure about what the ideal ‘open hand’ pattern looked like.
They had to do this to be confident that they had ‘open hand’ associated motor neuron talk and not something like ‘pinky toe flexing’ talk.
Finally, they programmed the robot hand to open only when the BMI detected the same or very similar ‘open hand’ patterns from Matt’s motor cortex. Luckily, the robot arm was able to do respond to Matt’s thoughts in real time, allowing Matt to actively turn his imagination into reality, as soon as he imagined it.
They used the same basic procedure to give the patients mental control over full robot arms and even mouse cursors.
However, instead of trying to invent a new sense for mouse cursor movement, they linked the movements of the mouse to other imagined hand movements.
This time Matt was told to imagine moving his hand to the right. His motor neuron activity associated with right hand movement was detected by the sensor, and the BMI would move the cursor on screen to the right.
Eventually, the BMI was good enough to allow him to play computer games, open up emails and even draw.
After these experiments were published, it wasn’t long before improvements were made by this research team and others. As you could see from the second video, the new additions really came a long way. They started with a basic thought controlled hand and moved to the development of a fully functioning arm that someone could use to drink coffee. Although we can’t use the technology to be Jedi’s just yet, the application of BMIs to help the paralyzed is developing rapidly and seems very promising.
TL;DR Paraplegics given a ‘helping hand’ by having computers use the activity from their brain cells to control robotic limbs and mouse cursors
Hochberg, L. R., Serruya, M. D., Friehs, G. M., Mukand, J. A., Saleh, M., Caplan, A. H., ... & Donoghue, J. P. (2006). Neuronal ensemble control of prosthetic devices by a human with tetraplegia. Nature, 442(7099), 164-171.
Collinger, J. L., Wodlinger, B., Downey, J. E., Wang, W., Tyler-Kabara, E. C., Weber, D. J., ... & Schwartz, A. B. (2012). High-performance neuroprosthetic control by an individual with tetraplegia. The Lancet
Pais-Vieira, M., Lebedev, M., Kunicki, C., Wang, J., & Nicolelis, M. A. (2013). A Brain-to-Brain Interface for Real-Time Sharing of Sensorimotor Information. Scientific reports, 3.
Author’s note: If you want more information on this research you can check out this video report on the work done by the Donoghue group: https://www.youtube.com/watch?v=ogBX18maUiM
If you thought this was impressive, there is another group of researchers using the same BMI technology with an M. Night Shyamalan-like twist that allows animals to use their thoughts to alter the behavior of other animals. And If you’re lucky, I might tell you about it next time.
Monday, April 1, 2013
Though insensitive, schizophrenia patients embody what some call “crazy”. Sufferers have a cognitive disorder which presents some common symptoms that include, auditory hallucinations, bizarre or false beliefs (delusions) and disorganized speech. They display behaviors similar to those on the streets of NYC loudly and erratically detailing the CIA’s constant attempts to spy on conversations with their best friend Lamar (who also happens to be a turkey sandwich).
Can the reason why some of these people develop this condition be due to their frequent use of high heels? The answer is….probably not. However, this did not stop one brave researcher from trying to prove that this could be the case.
In 2004, there was a scientific article published that detailed “evidence” suggesting a meaningful association between the use of high heeled shoes and individuals developing schizophrenia. In the paper, the author notes that different societies throughout history with a prevalent use of high heel shoes also had co-incidences of asylum visits and/or some record of some schizophrenic-like cases reported. The author then takes information from many unrelated studies and uses them to create a patchwork conclusion, based on correlations that weakly suggest a relationship between the schizophrenia and high heel shoe usage.
In his defense though, he did add that after a thorough search of the literature no evidence to the contrary was found.
After reading his review, and noting his bravery in reporting a farfetched argument, I have been inspired to announce something that I’ve known for years.
Facebook makes me poop.
There, I said it.
Ever since Facebook was created, I have gone to the bathroom more times than I can count. On top of that, I know my friends have taken more trips to the bathroom since the site went up. No one’s shown me any proof to say that it doesn't, so I must be right. Right?
Unfortunately, both my claim and the author’s are based on relationships most would not find promising enough to investigate, so it’s not likely that evidence to the contrary would be found. Disregarding that, just because evidence shows two factors changed during a similar period of time, does not mean one affected the other. Our “evidence” also doesn’t take into account other factors that may influence the both of the factors we are correlating. Lastly, coincidental increases in our correlational factors (i.e. more trips to the bathroom or increase in asylum admissions) may not be due to the ailment of interest (pooping or proper schizophrenia diagnoses), as there are lots of reasons someone might go to the bathroom or other ailments someone can have when being admitted.
For now it seems that people can continue to wear high heels, with the only fear being the inevitable foot pain that goes along with it.
TL;DR Keep your heels on.
Flensmark, J. (2004). Is there an association between the use of heeled footwear and schizophrenia?. Medical hypotheses, 63(4), 740-747. http://dx.doi.org/10.1016/j.mehy.2004.05.014
Tuesday, March 26, 2013
If you took some time out during your hectic workday to close your eyes, relax and take deep breaths, a few things could happen:
- People stare at you
- You get written up for wasting company time
- You feel a little more relaxed and potentially healthier
The third option is the one most of us would hope for and is also what many practitioners of meditative activities like Yoga, Qigong, Sudarshan Kriya (and a few others) report long after sessions. What these practices generally have in common are periods of positive cognitive reinforcement, relaxation and deep breathing techniques. These components are thought to be responsible for the practices’ attenuating effects on aging, stress and disease development. Though the benefits have been continually noted anecdotally and in many studies for a long time, how someone’s body might actually generate some of these effects after such activities has been treated as a black box and relatively ignored.
Unsatisfied with the lack of answers in this area, a few investigators tried to find out what biological forces might be responsible for the effects of these practices.
Most of the research centers on meditative practitioners and their white blood cells. These are the cells in the body that make up an essential part of the immune system by helping to fight off invading infectious entities like bacteria or viruses. A particular type of white blood cell was focused on in particular and is known as a neutrophil. In a sense, this type of white blood cell acts like a patrol officer. By constantly making rounds in the body, these cells are able to respond quickly (within minutes) to the first reports of a trespassing foreign entity. Following leads and clues (in this case a trail of attractive molecules), they are able to track down the “crook”. After arriving at the crime scene however, these guys take no prisoners and instead of arresting, they engulf and “digest” the perpetrating agent.
One of the reasons why these cells are able to act as they do is because of what’s inside of them.
Within white blood cells (and most other cells that make up your body) are genes. Genes act as a biological blueprint, giving the cell “instructions” on what kinds of things it should make and potentially what tasks it can perform. Individual genes give their own particular set of instructions to the cell and are important for making sure a cell “acts” in a way appropriate to a specific situation. For example, if your body is being attacked by a virus, the white blood cell genes not involved in dealing with the foreign agent may give out less or the same number of instructions; while the genes important for this process (i.e. following cues that lead to the virus or arresting/engulfing the virus), give more instructions. Being under attack by foreign entities however, isn’t the only time when gene activity may change. Genetic activity can also be altered during other physical/mental states.
Could the state induced by Yoga, Qigong and other meditative practices be causing genetic changes that make practitioners healthier?
A few inquisitive researchers wondered if this was true, so they did some experiments to find out. Essentially, they looked at the same genes in meditative practitioners and lay people and compared the number of instructions these genes produced. Several different research teams performing (generally) the same experiment found that the genes responsible for allowing white blood cells to live longer and preventing the spread of viruses gave out more “instructions” in the meditative groups.
However, just because the gene gave instructions, doesn’t necessarily mean the cell will exhibit any changes in behavior. In a way, it’s kind of like talking to a three year old.
Knowing this, a group of researchers took the investigation one step further. They wanted to see if the genetic differences between the groups might translate into a functional difference in the cells of the groups. To do this, they took the white blood cells (neutrophils specifically) from people in the different groups, placed them in separate dishes and let them fight it out with bacteria. Using an indicator that measures bacteria destroying activity, they found that the white blood cells from the group of people that meditated seemed to be more effective at destroying bacteria than cells from non-meditative practitioners.
Unfortunately, many of the studies only had a small number of subjects to draw from. This essentially limits the ability of the findings to be applied to many different people. However, the fact that several unassociated groups generated similar results, along with the promising functional data produced in the formerly mentioned study, suggests that there may be a real consistent underlying change.
If you now believe in the (genetic) power of meditation, feel free to try it yourself. If you need help there is now of course an app for that which helps you monitor your brain waves during meditation, so you can monitor its effectiveness (or at least that’s what the makers claim). If you’ve got a couple of dollars to shell out for the accompanying headset, you can find it here at: https://play.google.com/store/apps/details?id=com.personalneuro.transcend&hl=en
TL;DR White blood cells may help fight off infections better in people who meditate because of genetic differences; Scientists investigate this by getting into practitioners genes and by making bloods fight
1. Saatcioglu, F., Regulation of gene expression by yoga, meditation and related practices: A review of recent studies. Asian J. Psychiatry (2012), http://dx.doi.org/10.1016/j.ajp.2012.10.002
2. Sharma, H., Sen, S., Singh, A., Bhardwaj, N.K., Kochupillai, V., Singh, N., 2003. Sudarshan Kriya practitioners exhibit better antioxidant status and lower blood lactate levels. Biological Psychology 63, 281–291. http://dx.doi.org/10.1016/S0301-0511(03)00071-1
3. Dusek, J.A., Otu, H.H., Wohlhueter, A.L., Bhasin, M., Zerbini, L.F., Joseph, M.G., Benson, H., Libermann, T.A., 2008. Genomic counter-stress changes induced by the relaxation response. PloS one 3, e2576. doi:10.1371/journal.pone.0002576
4. Drescher, B., & Bai, F. (2012). Neutrophil in viral infections, friend or foe?. Virus research. http://dx.doi.org/10.1016/j.virusres.2012.11.002
5. Kuntsevich, V., Bushell, W. C., & Theise, N. D. (2010). Mechanisms of yogic practices in health, aging, and disease. Mount Sinai Journal of Medicine: A Journal of Translational and Personalized Medicine, 77(5), 559-569. DOI: 10.1002/msj.20214
The next post is the start of a series of posts on some well-known activities, and the not so well-known effects they may have on your body.
Also, feel free to leave comments. I am really just using these posts to generate some kind of discussion on interesting science. And if nothing else, at least feel comfortable enough to leave a question, no matter how ignorant you are of the topic (and even if you’ve only read the TL;DR). Enjoy.
Monday, January 21, 2013
Are you a man who spits on homeless people for fun? Do you regularly cut off pregnant women for the last seat on the bus? Are you really good at dodging child support payments?
If you answered “yes” to any of these questions, there may still be hope. Fortunately for you, the real measure of a man may have less to do with the measure of his character and more to do, from a biological perspective, with the measure of his taint.
Though not commonly thought of in this sense, from an evolutionary biological perspective, a good man is one who amply fulfills his role as a provider of DNA by passing his genes to many offspring. In order to do this, having good quality ejaculate is a must. But how good is your semen really?
To find out, you could sleep around and count the number of children you have, but that could be costly for a lot of reasons. A less expensive (and more reasonable) method could involve going to a doctor or a fertility clinic to have your semen analyzed. However, you would probably do this only after some fertility issues are noticed. This may be a time when there aren't many corrective actions to take. If you could assess your fertility much earlier, possibly even during puberty with an assessment that is as simple as a breast exam, you might intercept the issue and increase the chances of passing down your genes.
So why not measure your taint?
Finding an easy to assess indicator of male fertility and genital health were two of the many motivations behind research suggesting a link between smaller male taint lengths and decreased fertility. But how exactly did they find this out?Well, if you were a male participant in one of the studies(ref 1), the researcher would have started by asking personal questions like “When was the last time you ejaculated?” (Note: He’s not interested in how you spend your Friday nights; times between ejaculations are thought to affect semen quality(ref 8*)). Sometime afterwards, you would be asked to ejaculate into a container. Then finally, you would be told to take off your underwear, lay down exposed on an examining table, and take the lithotomy position (an example of which can be seen in Figure 1). You would then have your taint (also known as anogenital distance and shown beautifully in Figure 2) measured twice with a stainless steel digital caliper. Feeling uncomfortable yet? Luckily, 124 young men already did this for science, so you don’t have to.
After many a seed was sown, counted and analyzed, the researchers from this study, as well as similar study conducted at fertility clinic comparing fertile and infertile men (ref 2), reported that smaller measurements from the center of a man’s anus to the most posterior portion of his testicles were associated with decreased fertility. Shorter taint lengths/anogenital distances were correlated with ejaculates that contained smaller volumes of semen, along with sperm that had poor directed movements and a smaller size and shape. (In case you’re curious, the mean anogenital distance in the infertility study(ref 2) for fertile men vs. infertile/childless men was 44.6 mm vs. 31.8 mm, do what you will with these numbers….).At first glance, this seems like a popular science study just using bizarre research findings to grab attention. However, there is actually an important underlying connection.
The relationship between anogenital distance and fertility is thought to begin before the male is even born. While the fetus is still developing, there comes a time when male sex hormones (also known as androgens), like testosterone, become critical for making the switch from the female reproductive system (the genetic default) to a male reproductive system. This period of time is known as the male programming window. During this window, testosterone becomes a signal for the extension of the taint and for the maturation of cells in the testes that maintain and house premature sperm (known as Sertoli Cells). Testosterone is so crucial at this point that suppression of it’s levels at this time can lead to misplaced urethra openings (hypospadias) and testis that have difficulty dropping (cryptorchidism)(ref 3). So if you’re a male who appreciates his taint, the potential to have kids or peeing straight into the toilet, this was a very important time for you.The ideas on how this process works wasn’t dreamt up by some scientists obsessed with taints. They were also based on studies and experiments that suggested there were time sensitive effects of testosterone on male genitalia.
Researchers found that when babies are birthed by mothers with higher than average levels of phthalates (chemicals found in plastics that are thought to suppress male sex hormones), their offspring tend to have smaller taints(ref 4). Though one would hope that growth spurts during puberty might offer some compensation, there are studies suggesting that adult males with lower testosterone levels generally have smaller taints, and even lower quality sperm(ref 5). However, these are just correlations; because the participants from the study live their lives outside of the laboratory, there are many other influential factors that could have led to these results, so researchers could not conclude for certain that the low testosterone levels (or some other action of phthalates) contributed to the development of smaller taints.Fortunately for us, when it comes to genital development, humans ‘taint’ all that special. Rats go through a similar development process. Researchers took advantage of these similarities to more conclusively assess the effects of low androgen exposure on taint size and fertility. Pregnant female rats were injected with phthalates to see how their sons’ genitals would develop. They found that not only did the mother’s small tainted male babies become small tainted adults, but that these offspring were also less fertile(ref 6).
So we’ve seen that there is some connection between male babies and adults with small taints also having low levels of androgens (male sex hormones). We’ve also noted that when manipulated in rodents, low androgen levels in utero are followed by the development of males that are less fertile and have smaller taints. However, if one were to perform the critical experiment to show this also applies to humans, it might involve making similar manipulations before birth which is unethical, to say the least.However, one experimental study may have skirted the ethical line to bridge this gap in knowledge. Investigators in England injected testes from aborted human fetuses into the bodies of mice to examine the effects of human testes testosterone production on taint length and fertility. By administering phthalates at different times during fetal development, the researchers were able to note when androgens such as testosterone, may influence taint size and fertility. The results from the study showed that if the mice with human testes had testosterone suppressed at a time right before birth (slightly outside of the expected male programming window) they developed smaller taints and less Sertoli cells (which harbor premature sperm and would likely affect fertility)(ref 7).
While the seminal results from these studies provide a strong basis for understanding the taint length-fertility relationship, it is worth mentioning that no study is perfect. For example, in the first study mentioned(ref 1), the participants were generally 18-22 year old young white males. This lack of diversity in age and race limits how much of the much findings can be related to other kinds of men. Fortunately due to the support of the many other studies and experiments listed, there’s a strong indication that the measure of a man’s taint may generally be a sign of his fertility. However, it still couldn’t hurt to have more guys participate in studies like this to strengthen confidence in the results. So the next time a stranger in a lab coat asks you to pull down your paints, ejaculate into a container and lay down on his table for a taint check, please, just do it. It’s for science (hopefully….).
TL;DR: Studies involving guys dropping trou, rat hormone suppression, and mice grafted with aborted human testes suggest that fetal testosterone exposure may be the reason why human males with small taints are generally less fertile.
1. Mendiola, Jaime, et al. "Shorter anogenital distance predicts poorer semen quality in young men in Rochester, New York." Environmental health perspectives 119.7 (2011): 958. DOI: 10.1289/ehp.1103421
2. Eisenberg, M. L., Hsieh, M. H., Walters, R. C., Krasnow, R., & Lipshultz, L. I. (2011). The relationship between anogenital distance, fatherhood, and fertility in adult men. PLoS One, 6(5), e18973. DOI: 10.1371/journal.pone.0018973
3. Sharpe, R. M. (2008). “Additional” Effects of Phthalate Mixtures on Fetal Testosterone Production. Toxicological sciences, 105(1), 1-4. DOI: 10.1093/toxsci/kfn123
4. Swan SH. (2008). Environmental phthalate exposure in relation to reproductive outcomes and other health endpoints in humans. Environ Res 108:177–184. DOI: 10.1016/j.envres.2008.08.007
5. Eisenberg, M. L., Jensen, T. K., Walters, R. C., Skakkebaek, N. E., & Lipshultz, L. I. (2012). The relationship between anogenital distance and reproductive hormone levels in adult men. The Journal of urology. DOI: http://dx.doi.org/10.1016/j.juro.2011.10.041
6. Scott, H. M., Hutchison, G. R., Jobling, M. S., McKinnell, C., Drake, A. J., & Sharpe, R. M. (2008). Relationship between androgen action in the “male programming window,” fetal Sertoli cell number, and adult testis size in the rat. Endocrinology, 149(10), 5280-5287.DOI: 10.1210/en.2008-0413
7. Mitchell, R. T., Childs, A. J., Anderson, R. A., van den Driesche, S., Saunders, P. T. K., McKinnell, C., ... & Sharpe, R. M. (2012). Do phthalates affect steroidogenesis by the human fetal testis? Exposure of human fetal testis xenografts to di-n-butyl phthalate. Journal of Clinical Endocrinology & Metabolism, 97(3), E341-E348 DOI: 10.1210/jc.2011-2411
8. Moshe Matilsky, Shlomo Battino, Moshe Ben-Ami, Yoel Geslevich,V. Eyali and Eliezer Shalev (1993). The effect of ejaculatory frequency on semen characteristics of normozoospermic and oligozoospermic men from an infertile population. Hum. Reprod. (1993) 8 (1): 71-73.
Editor’s Note: *The reason for asking participants when they last ejaculated was presumably based on the idea that shorter times between ejaculations lower sperm volume and other attributes. However, there are many studies about abstinence and semen quality in human males and many of them report contradicting results. Comments and some references to these results are noted in the introduction of this publication, Jonge et al, 2005 doi:10.1016/j.fertnstert.2004 03.014