Symptom 1: Impulsive-Reactive Aggression

Be sure to head over to Oscillatory Thoughts for our first symptom of the Zombie Brain.

The Living Dead Brain: What Forensic Neuroscience Can Tell Us about the Zombie Brain

Dr. Timothy Verstynen & Dr. Bradley Voytek, Zombie Research Society

This is a cross-post between Oscillatory Thoughts and Cognitive Axon. Stay tuned to both sites over the following days leading up to Halloween for updates on our model of the zombie brain.




What can neuroscience teach us about surviving the zombie apocalypse?

What makes a zombie a zombie or, more importantly, what makes a zombie not a human? Philosophers contend that a zombie lacks that qualia of experience that belies normal consciousness.

However this is a less than satisfying explanation for why the lumbering, flesh eating creatures are pounding outside the door of your country farmhouse.

Beyond the (currently) immeasurable idea of consciousness or the whole supernatural “living dead” theory, zombies are characterized primarily by their highly abnormal but stereotyped behaviors. This is particularly true in more modern manifestations of the zombie genre wherein zombies are portrayed not as the reanimated dead, but rather as living humans infected by biological pathogens. They are alive, but they are certainly not like us.

Neuroscience has shown that all thoughts and behaviors are associated with neural activity within the brain. Therefore, it should not be surprising that the zombie brain would look and function differently than the gray matter contained in your skull. Yet, how would one know what a zombie brain looks like?

Luckily, the rich repertoire of behavioral symptoms shown in cinema gives the astute neuroscientist or neurologist clues as to the anatomical and physiological underpinnings of zombie behavior. By taking a forensic neuroscience approach, we can piece together a hypothetical picture of the zombie brain.

Over the course of the next week, Oscillatory Thoughts and Cognitive Axon will team up to show our hypothetical model of the zombie brain. Each day we will present a new "symptom" associated with a zombie behavior and show its neural correlates in our simulated zombie brain.

This entire endeavor is partly an academic "what if" exercise for us and partly a tongue-in-cheek critique of the methods of our profession of cognitive neuroscience. We’ll be breaking up the workload and alternating days (hey... we gotta work our real jobs too) so be sure to check both places for the newest updates on zombie neuroscience.

DISCLAIMER: We need to be very clear on one point. While we sometimes compare certain symptoms in zombies to real neurological patient populations, we are in no way implying that patients with these other disorders are in some way “part zombie”. Neurological disorders have provided critical insights into how the brain gives rise to behavior and we bring them up for the sake of illustration only. Their reference in this context is in no way meant to diminish the devastating impact that neurological diseases can have on patients and their caregivers.

When good science is used badly

In a recent New York Times op-ed piece, branding guru and self-described scientist Martin Lindstrom gives a perfect example of why scientific tools should only be used by professional scientists and not self-trained hacks.  In his article titled "You love your iPhone. Literally." Mr. Lindstrom made the case that we are not addicted to our smart phones, but that we have established a relationship with our technology that is on par with the process of "love."

Mr. Lindstrom would have you believe that he's not just giving his professional opinion as a marketing consultant, but that he has scientific data to validate this claim.  However let's take a close look at these spurious claims.

First, Mr. Lindstrom describes an imaging experiment that he undertook to see if marketed brand names engage the same brain circuits as religious symbols.

"A few years back, I conducted an experiment to examine the similarities between some the world’s strongest brands and the world’s greatest religions. Using functional magnetic resonance imaging (fMRI) tests, my team looked at subjects’ brain activity as they viewed consumer images involving brands like Apple and Harley-Davidson and religious images like rosary beads and a photo of the pope. We found that the brain activity was uncannily similar when viewing both types of imagery."

To someone who doesn't live in the world of brain images all day (like I do), this sounds pretty promising right?  You might think, "Huh? My brain is activated the same way when I see the Apple logo as when I see the Madonna of Brugges."  But that is nowhere close to what these results reflect.  Now I haven't seen the details of his study, so I can't lay claim to the soundness of his methodologies.  However, I can point out two major inconsistencies in his interpretations.

First, seeing "uncannily similar" brain areas engaged when seeing objects and religious symbols is not that surprising. It's not surprising that visual symbols are encoded in the same brain networks.  They're visual stimuli with interpretive meaning.  But that doesn't mean that you value them the same way.  A symbol may just be a symbol as far as the brain is concerned.

Second, Mr. Lindstrom is committing one of the most basic of scientific fallacies.  Not detecting a difference between two conditions isn't the same thing as there not being a difference.  It is called "arguing the null hypothesis".  In science we can't say anything definitive about differences that we don't see, only difference that we do.  Just because monkeys and children pick their noses at the same rate does not mean that they're the same creature.  But this is essentially Mr. Lindstrom's conclusion.

Okay, so he's a bad fMRI researcher.  Big deal... there are a lot of them these days.  Let's look at some of Mr. Lindstrom's other data.

"...I gathered a group of 20 babies between the ages of 14 and 20 months. I handed each one a BlackBerry. No sooner had the babies grasped the phones than they swiped their little fingers across the screens as if they were iPhones, seemingly expecting the screens to come to life."

This again is wrong in so many ways.  As anyone who has ever interacted with children can tell you, they aren't the most coordinated of folks.  In fact the brain systems that regulate our movements aren't fully developed until you're almost a teenager.  Did Mr. Lindstrom give phones to children from countries where iPhones aren't as common for a control group?  Presumably not, but that would be one way to see whether this behavior is just random grasping from people without fully formed cerebellums.

Perhaps most importantly, children imitate adults.  They adopt the behaviors of the people around them as a way of learning the world.  That's a key part of development (as evidenced by these two kids who obviously don't know how to speak, but sure know how to act like it). Just because children are imitating their parents doesn't mean that they value them in the same way as Mr. Lindstrom appears to be suggesting.

Finally, and perhaps most egregiously, Mr. Lindstrom reports on yet another brain imaging study.  In this case he presented either a visual movie of a ringing phone or the sound of a ringing phone.  

"In each instance, the results showed activation in both the audio and visual cortices of the subjects’ brains. In other words, when they were exposed to the video, our subjects’ brains didn’t just see the vibrating iPhone, they “heard” it, too; and when they were exposed to the audio, they also “saw” it. This powerful cross-sensory phenomenon is known as synesthesia."

Had Mr. Lindstrom bothered to go to Wikipedia, he would know that this effect is not synesthesia.  Synesthesia is an inherent, hard-wired "cross connection" in the brain.  It's not learned.

What Mr. Lindstrom is in fact reporting is the very simple result of Hebbian learning: "neurons that fire together wire together."  Seeing visual areas light up with certain auditory (or tactile) stimulation is a fairly commonplace finding in the brain imaging literature.  We often both see the phone light up (or vibrate) and hear it ringing at the same time.  Eventually an association is formed within the brain.  Mr. Lindstrom would probably see the same thing if he showed his subjects a picture of a baby crying, a doorbell, etc.

Finally, there's this last bit of "evidence" (quotes are mine).

"But most striking of all was the flurry of activation in the insular cortex of the brain, which is associated with feelings of love and compassion. The subjects’ brains responded to the sound of their phones as they would respond to the presence or proximity of a girlfriend, boyfriend or family member."

There are a host of other areas that are also associated with "love and compassion" in the brain.  There's not one single area that encodes these concepts.  As far as I know, there is no definitive conclusion about where the concept of "love" is encoded in the brain.

So this becomes a guilt by association conclusion: brain area A is active when experiencing X and Y, therefore X is the same as Y (or worse, X causes Y). If Mr. Lindstrom had seen the same area of the brain engaged when he presented an image of a fire-truck and an image of a t tomato, it doesn't mean that your brain thinks of the truck as being made of tomatos (nor that tomatoes are baby fire-trucks).  Sadly, this is a fallacy that many established neuroscientists also make.  But that's a topic of another post.

As a professional neuroscientist, my reaction to the findings Mr. Lindstrom presents in his op-ed is "So what?" Nothing he reports provides a shred of evidence that we "love" our iPhones, at least neuroscientifically speaking. Nor does he show that the experience of using your smart phone is the same as falling in love or having a religious experience.  All Mr. Lindstrom demonstrated was what can happen when the tools of sciences are placed in the wrong hands.

Perhaps all neuroimaging articles should come with the disclaimer: "Performed by trained professionals, do not try this at home."

Cloud computing in the brain

I meant to post on this earlier this summer but got distracted... work & life have a way of doing that.

This past July saw one of my most grueling projects finally come to a close. Published in the Journal of Neuroscience and titled “How each movement changes the next: an experimental and theoretical study of fast adaptive priors in reaching" this paper goes well beyond the topic of simple motor control and into fundamental issues about how our brains learn from experience (this is the reason why it took over 2.5 years to get through the review process!).  In particular we show how neurons in the brain might do something akin to cloud computing.

Confused? Let me explain.

First I'll have to talk about a little hard science for some background.  What my co-author and I found was that whenever we move, our brain keeps track of where we go.  Over time, the motor control regions of the brain begin to generate an internal model of the recent movements we've made.  It then uses this memory when we make future actions.  For example, if I keep reaching for this soda can on my desk (and return it to the same position), then over time my brain retains the history of all the reaches I've made to that same spot on my desk.  Over time my reaches to the soda get a little more accurate.  So in a sense, practice makes perfect.

Now, here's the kicker... if I suddenly want to reach for something else ("Hey, that cookie over there looks mighty tasty!") then my brain biases this new movement in the direction of the soda can. We don't really notice it that much, but it's detectible with the fancy machines that we use to monitor your movements.  The more often I reach for that soda can, the more biased my reach for the cookie gets.

It turns out that this type of learning is really sophisticated and follows what appears to be rigid statistical principles.  What I mean is that our brain somehow encodes our recent actions as a prior probability distribution (think of the "bell curve" you've heard about).  It then integrates this prior with all the incoming sensory information you're getting from your eyes, your hand, etc.  This integrated information is then used when you make your next reach.  The stronger the prior, the more biased your future actions will be.  The stronger the sensory input is, the less biased you'll be.

For the math-nerds out there, this is a form of adaptive Bayesian inference.  I wont go in to the awesome details of Bayesian statistics because I don't want to lose 90% of whoever it is actually reads these posts ("Hi Mom!"). This is a branch of mathematics that's used to filter Spam from your inbox, improve images of the stars from telescopes, optimize airline travel, make video games more difficult, and almost everything else that's cool these days.  Needless to say, these are some pretty freaking sophisticated computations that our brains are doing almost effortlessly.  And not just for any high level cognitive process (I mean this process worked in both Shakespeare's brain and in Pauly D's brain)... but for something as simple as reaching for a can of soda.

Okay... hopefully I haven't lost anybody.  Because here's the truly insane part.

Through simulations of neural tissue, my co-author and I found that this really cool mathematical computation likely happens through a form of "cloud computing" in the brain.  For those of you who don't know, cloud computing is the process by which a computation is broken down into a set of little chunks and then distributed to a whole bunch of computers that live in the vast ether of the internet (Note: So technically what I'm talking about is more similar to a computer clusters, but "cloud computing" is the hip new thing these days).  You know those nasty things called "botnets" that take down servers in foreign countries or send you all that spam in your inbox... they're cloud computing gone bad.

We found that a similar principle might work in the brain.  There might not be a single neuron or group of neurons that store this statistical prior.  Instead, we were able to show how this memory can naturally emerge in the dynamics of the information passing between neurons.  Thanks to Hebbian learning ("neurons that fire together wire together") our brain is able to store little bits of information distributed across a mass of connected cells.  Basically populations of neurons remember their collective pattern of activity from the recent past.  Over time, this distributed collective memory shapes the way the network responds to new inputs.  Eventually, this learning exhibits very sophisticated properties that look almost exactly like human behavior, as well as the expectations of statistical theory.  So the whole is, in fact, greater than the sum of its parts.

Let's put this all together shall we?  We've got a group of neurons in your brain that are building a complex statistical model of everything you just recently did. But this model isn't encoded by the activity of any one cell or even in the response properties of a group of cells.  Instead this model simply exists in the abstract dynamics of how these neurons talk to one another.  Mind blown yet?

Now to be completely honest this is hardly the first time that someone has come up with the idea that information is broken down and stored across a network of neurons (in fact there's a formal name for this called "sparse coding").  But what's interesting from our study is that complicated, mathematically principled information can just emerge naturally in the brain thanks to the fact that neurons are recurrently connected (i.e., send information back and forth) and they have associative learning.  This dramatically increases the complexity of information that our brain can store.  Information isn't just encoded in how the cells fire, but also in how they talk to each other as a group. It's a sort of meta-level type of information storage.

Let's end with this... our simulation used about 180 simulated neurons (with 32,400 connections) and we were able to do some pretty fancy mathematical processing.  The human brain has more neurons than there are stars in the Milky Way.  Each of these neurons has, on average, 10,000 connections or so.  A conservative estimate puts it as about 100 billion neurons with about 100 trillion axons.   Think about just how complex of a biological computer that this system could hold!

Yup.... crazy stuff like this is why I do science!

If you don't like the message, kill the messenger

As some of you may know, one of my goals in life is to facilitate the role of science in society.   Last week I came across a little gem that reminds me of what we, as scientists, are up against as far as how science is discussed outside the lab.

Now before I start, let me be honest.  There have always been, and always will be, those who will instinctively disavow science.  For some it's a matter of fear ("That appears to threaten my world view and scares me").  For others it's simple ignorance ("That doesn't easily make sense to me, so I don't believe it").  But for a few it is really more a matter of power ("By minimizing science and its scope, I can act how I want regardless of what evidence there is that I shouldn't.")

The first two groups I can understand and even empathize with.  It's our nature to be cautious and skeptical.  Hell, as a scientist I'm trained to be skeptical and to wait for mounting evidence to make the case that I should reject my current beliefs.   However, usually those who dislike science out of fear or ignorance can be reasoned with if approached in the right way.  Remember that even Pope John Paul II, a man who lead an institution that was terrified of the concept of evolution, eventually conceded that it exists.

It is that third group of science denier terrifies me. And that brings me to what started this whole post.  Check out this clip of Presidential candidate Rick Santorum speaking to a law school audience last week.

Let's listen very carefully to what Mr. Santorum says.  First he appeals to authority" "Because I believe what the Catholic church teaches with respect to homosexuality" he therefore should be allowed to hold his beliefs that same-sex couples should not have equal rights in terms of marriage and adoption.  Now if it were just a personal belief that would be fine.  We all have to appeal to authority at some point in order to have baseline assumptions with which to act in the world.  But when faced with new evidence that those assumptions are incorrect, a logical person would change the assumption.  Mr. Santorum inherently acknowledges this fact when he goes on to say that there is no evidence to refute his "bigoted" beliefs.

But now listen to what Mr. Santorum says when confronted with two critical pieces of information that there is, in fact, evidence to refute his assumptions.  First the fact that the American Psychiatric Association (not the American Psychological Association as stated in the video, although they take the same stance) delisted homosexuality as a mental illness in the DSM-III in1974.  This, by the way, was after numerous empirical studies showing that, in all other aspects, homosexuals had no other presenting symptoms or negative life outcomes than heterosexual individuals.  Second, the fact that there is overwhelming peer-reviewed research by behavioral scientists that children growing up in same-sex households are no different, in terms of mental health and emotional well-being, than those who grow up with heterosexual parents.

Mr. Santorum replies "The American Psychological Association is made up of people who agree with the American Psychological Association." He then follows up with this gem, "A lot of psychologists don't belong to the American Psychological Association. A lot of doctors don't belong to the American Medical Association."

Now keep in mind this is a serious (albeit unlikely) candidate for the GOP nomination.  He's a trained lawyer and served in Congress both as a Representative and a Senator.  So he should, by all accounts, be a very bright and logical man.  Yet his response to just the existence of scientific evidence refuting his beliefs is the same as that taken by the lunatic anti-science fringe: if you don't like the message, attack the messenger.

As a scientist, I'd be fine if Mr. Santorum argued with the science itself.  Every study and every field has its weaknesses. Had he argued that showing a lack of a difference is not the same thing as there not being a difference, he'd actually be correct.  In science, we call it "arguing the null."  Had he said that the research was still preliminary because the children adopted by homosexual couples are just now reaching adulthood, that would also be a valid and reasoned response.

But that wasn't Mr. Santorum's reaction.  This initial reaction reveals something far deeper than a simple lack of understanding of the issue.  It shows a complete and utter lack of respect for the science being discussed.  In fact, he turned the appeal to authority on it's head.  It's okay for Mr. Santorum to hate homosexuality because the Catholic church says so, but it's not okay for scientists in the APA to feel that there's nothing wrong with homosexuality because they're just preaching to the choir.  Do you see that Catch-22?

If Mr. Santorum were the only major politician to act this way toward science, I could let it slide.  He'd be annoying but not threatening.  Unfortunately this is the rule these days and not the exception.  For many politicians, as well as media personalities and a growing minority of the U.S. population, refuting a scientific fact outright because scientists say it is a badge of honor.  It's something to brag about.  In fact, we live in a world where most of the contenders for a major political party's presidential nomination don't believe in evolution or global climate change.  Both of which have thousands (that's right.. thousands!) of empirical publications supporting them.

And that brings us back to the motive. As I mentioned before, Mr. Santorum has to be a smart and logical man in order to get as far as he did.  The same is true for the other leaders who instinctively attack science as a whole (with the exception of Mrs. Bachmann who's a whole other kind of crazy).  I'm afraid, their attack comes from a need for power.  "I can ignore the research on homosexuality and evolution because I want to court the religious vote."  "I can ignore the evidence of climate change because I want to court the industries who it will affect."

Unfortunately, this is an endgame move in the debate.  There's nothing you as a scientist can say or do that will change their beliefs because their ignorance is a source of power.  Arguing with those who take this stance is like arguing with the three year old holding his fingers in his ears... you just have to wait until they grow up so you can talk to them like an adult.

Update: As if on cue, last night's GOP primary debate featured Rick Perry demonstrating my point perfectly.  "Just because you have a group of scientists standing up and saying 'Here are the facts'... Galileo got outvoted for a spell."  The important point being distorted by Mr. Perry is that Galileo was not outvoted by his scientific peers... he was outvoted by the Catholic Church.  His "natural philosophy" peers respected and built off of his work.  In fact, by taking such a stance against the empirical findings, Mr. Perry is putting himself in the same boat as those who "outvoted" Galileo.

Virus-guided laser neurons and the need for creative exploration

Like all meetings, this year's Human Brain Mapping conference was packed with the ubiquitous blend of brilliance and social awkwardness that permeates nearly every neuroscience meeting. That's why I like science.

Real geeks, unlike chic geeks, embrace the fact that they live 90% of the time in their heads, trying to frame the world that they see into the science that they know. Either trying to understand how something works or what would happen if two disparate things were suddenly fused together to make something new.

Most of us are constantly living in our own heads. That's why the "absent minded professor" isn't really much of a stereotype as it is a valid descriptor of our behavior.

But it is this mental wandering that makes good scientists great. Daydreaming has it's creative advantages. Those "what if?" or "how did that work?" scenarios that constantly bounce around within our cranium are the key to pushing science forward.

Case in point, the story behind "virus-guided laser neurons" (also known as "optogenetics"). For those of you who have never heard of optogenetics, it's the mind blowing technology by which viruses are used to insert genetic material from algae or bacteria into the neurons of living mammals. This genetic clipping changes the properties of neurons so that they will either fire or not fire in response to light pulses of particular wavelengths.

You heard that right. Viruses change neurons so that they can be controlled by lasers... in living animals. I'll let you think about that one for a minute.



This technology was developed by Karl Deseroth and his lab at Stanford around 2004. In just a short time, this tech has revolutionized neuroscience and lead many to speculate (privately and openly) that the Nobel is waiting in the future.

Dr. Deseroth was featured as a keynote speaker last week and while the whole lecture was absolutely fascinating, something he said at the beginning caught my attention. Deseroth mentioned that when his lab started working on the idea of optogenetics, they were using funds from a grant from the National Institute of Mental Health that had proposed to do something VERY different. But his lab wanted to try this new venture and they took the risk and it paid in dividends.

"It's a great example of the need for creative exploration," Deseroth said.

And therein lies one of the many problems facing today's researchers. Funding agencies like the National Institutes of Health (NIH) are taking fewer and fewer risks in science. They're hedging their bets on what seems to be the safest horse and in the process stifling most of the creative processes that lead to developments like optogenetics. As the government cuts more funding to science and education, what's left in the pot gets distributed mainly to the established laboratories who are building on established ideas.

Ask anyone who's written an NIH grant recently about the process. Go ahead, buy them a beer. They'll go on at length about how you need to have already finished half the experiments that you "propose" to do in the grant application. This is before it's even considered "fundable." Indeed, the average age at which researchers get their first full NIH grant is now 43 years old! Consider that most professors start their first position in their mid-to-late 30's.

As a result, most scientists in my field spend a vast majority of their time designing and performing research projects that they don't really want to do. They write grants to tell the NIH what it wants to hear. They'll write grants creatively dancing around the projects that are of interest to them, so that they can get the funds to do the real science.

I've even had one established scientist (with decades of experience in neuroscience) tell me that he always writes grants knowing that he'll only do 50% of what he proposes. He'll then spend the other 50% of funds on projects he really wants to do.

This problem is compounded when you consider that, in neuroscience, the current funding rates for grants at the NIH range from ~2.5-16.0%, depending on the agency (down from a stable ~20-25% in the 1990s). That's a lot of highly intelligent brain power being wasted on useless dead ends that could be spent creatively exploring something really interesting.

Unfortunately, that's the dirty secret of the world in which we do science in this country. Unless it changes, the US may stop becoming the place where people can turn crazy ideas like making virus-guided laser-neurons into a reality.

In the meantime, I'm going to keep on daydreaming my weird science ideas.

(Image taken from Technology Review)

Moving over and starting anew

Well it's been a little while, but I've decided to start putting my thoughts to digital paper again. So I've shifted all the old posts from my old blog (Scientia Publica) to the new domain that better encapsulates my interests. Stay tuned for more to come soon.