Cat brains offer insight to supercomputer design

April 18th, 2010 by Bay McCulloch

Researchers at the University of Michigan are studying feline brain cells as a model for a new generation of supercomputers that can process and recognize information in a similar way as humans. Such brainy computers will hopefully be able to accomplish more simultaneous processing and complex decision making. Microchips in conventional computers usually rely on transistors that switch on and off to represent data in binary code. The new technology that is being developed at the Univeristy of Michigan instead use "memristors," which are circuit elements that can actually remember information. For example, when you turn the voltage off to the device, memristors retain information about how much voltage had been applied and for how long. A parallel can be drawn between memristors and the synapses beween brain cells (neurons) because they too 'remember' information about the strength and timing of electrical signals from the neurons.

In a conventional computer, logic and memory are located in different parts of the circuit and each element is only connected to a few neighboring elements, resulting in a linear form of operation. Such linear processing allows computers to perform simple tasks, but makes multitasking difficult. Brains obviously can perform many different computations at once, and the goal for the memristor devices is to mimic the interconnected nature of the brain. The researchers devised a paradigm similar to how neurons are connected and connect two circuits through a memristor. With this technology they hope to make a computer brain that is about as smart as a cat (sorry dog lovers). From then they hope to build an even bigger system containing hundreds of artificial neurons connected by memristor synapses.

Why do we like whom we like?

April 4th, 2010 by Giaynel Cordero-Taveras

Along with blooming flowers, comes the promise of new relationships. When spring arrives, new couples can be seen holding hands while strolling under the beautiful emerging sun. But, what is love and how does it happen? In Annie Reed’s words from Sleepless in Seattle “love is like magic.” But what makes us fall in love with that one person, or moreover, why are we attracted to one person giving us that unique feeling of magic.

Many theories have been proposed on the science of falling in love, but most share a common theme that love is comprised of intimacy, compassion, attraction, and attachment. How these feelings develop is often described in three stages. The first is lust or physical attraction driven by sexual hormones in men and women. The second stage is attraction, but not the sexual kind, rather the “crush” kind. Adrenaline is responsible for those sweats and rapid heart beats you experience when someone you are attracted to approaches and dopamine is responsible for that feeling of pleasure and energy you get when thinking about or being with your crush. The third and final stage is attachment. This stage is usually due to oxytosin and vasopressin both hormones which lead to a feeling of attachment and intimacy with your partner.

Finding someone attractive at first sight is a different story. We are for the most part attracted to people who are compatible with us in socioeconomically, intellectually, religiously, and ethnically. However, these factors only seem relevant after two people have gotten to know each other. But what makes you turn your head, and what makes you feel a connection to a person without getting to know them? Scientific studies attribute attraction to evolution. We search for characteristics that have been engrained in us since the first Homo sapiens. A symmetrical face for both men and women is said to be most attractive while for women a youthful hourglass figure is attractive because evolutionary speaking, it means the woman is healthy for child rearing and carrying on a male’s genes. Women are said to be more attracted to men with angular faces and prominent jaws and greater muscle mass signs of greater testosterone levels, therefore more protection. Clear and smooth skin, fuller lips, bright eyes, and lustrous hair are also signs of attraction as evolutionary speaking they signify health.

Helen Fisher, the author of the book Why him? Why her? suggests that attraction is due to hormone levels. According to Fisher, hormones attract other hormones and so a high level of a hormone in one person can attract a high level of hormone in another person. This leads to certain personality types in humans which she has outlined.(Check out a more detailed explanation of her work at http://www.tellinitlikeitis.net/2009/01/why-him-why-her-helen-fisher-personality-test-understanding-your-personality-type.html) Other factors such as scent, which actually deals with pheromones that signal brain responses of attraction, and personal history such as whether or not someone reminds you of your first love, is more personal and specific to a person in the laws of attraction. Aside from all these evolutionary qualities people often search for a mate who shares similar characteristics in hopes of building a family.

One thing though that most scientists agree is that attraction and love is a result of fortuitous encounters. A chance meeting can lead to a life together. Sometimes love and relationships follow the saying “in the right place at the right time.”

Dumbledore’s Pensieve: Fiction or Reality?

March 29th, 2010 by Nisha Deolalikar

Neuroscientists and lay people alike have always been intrigued by the human brain’s extraordinary capacity for long-term memory. Very often we find ourselves going about our day-to-day lives when we suddenly encounter a stimulus that jolts us back to an earlier time and place – such an application of long-term memory can easily send us back months or even decades. Yet, this instantaneous form of recall is very often unexpected as well as involuntary. A number of comparisons have informally been drawn between the human brain and an indefinitely large filing cabinet, but a pressing question remains: how do we locate the files (memories) that we need exactly when we need them?

Surely we have all experienced the frustration of not being able to recall a particular fact when we wish to recall it, only to suddenly remember at a later time when it is not at all necessary. Wouldn’t it be wonderful, then, to have at our fingertips a device like Albus Dumbledore’s pensieve (Harry Potter) – a utility that helps us systematically sort through and organize our memories?

Recent research conducted at the University College London suggests that, in the not-so-distant future, functional Magnetic Resonance Imaging (fMRI) could be our pensive. Essentially, these researchers maintain that it is possible to identify the type and location of certain memories while the human brain is functioning normally. If these findings are developed further, they could potentially lead to the creation of a sort of memory map – a diagram of the human brain that would locate the individual positions of memory traces.

Despite the published study, the findings of the UCL research remain controversial for several reasons. Can the human brain really be likened to a filing cabinet? Why is memory-mapping even useful? And could fMRI thereby be the tool that helps our generation finally understand the intricate workings of the human memory and mind?

Cultural Neuroscience: An Intersection between Anthropology and Neurobiology

March 2nd, 2010 by Nisha Deolalikar

As we go about our day to day lives, it’s often easy to notice that people from different backgrounds think differently (an example would be the stereotypical Asian kid who has seemingly no difficulty in tackling math problems). However, it’s a bit harder to figure out exactly why these differences exist – and whether they are biologically or culturally based. Is there a “math gene” present in some people and not in others? Or is one’s intrinsic ability at a discipline the result of family values and upbringing?

Recent research suggests that the linkage between culture and biology determines the way that we view problems in the world. Eastern and Western subjects were asked the same questions while being examined through Functional Magnetic Resonance Imaging (fMRI) techniques – different regions of their brains were activated even when the subjects ultimately came up with the same response. For example, the Chinese subjects used one area of their brain to compute a basic math problem such as 3+4, while American subjects used a completely different region. Both groups ultimately arrived at the correct answer, of course, but these differences illuminate interesting biological phenomena about the influence that culture has on biology.

Of course, it is possible that these differences are due to a difference in biology all along – perhaps people from Eastern cultures simply have a different “math gene” than the rest of us. But consider the alternative – perhaps our cultural values and upbringing shape our neural development and perception. Further research may bring us closer to the truth.

Addicted and Obsessed

February 21st, 2010 by Umaima Ahmad

As we loom nearer to the publication of the American Psychiatric Association’s (APA’s) publication of the Diagnostic and Statistical Manual of Mental Disorders (DSM), fifth edition, there are some key changes being made. One of the proposals is to include new addictive disorder – "behavioral addictions" such as gambling. It’s simple enough to dismiss an obsession or compulsion as an addiction, but that refers merely to a cycle that is being perpetuated, not the way in which it is being perpetuated. One of the DSM criteria for both obsessive-compulsive personality disorder and substance-use disorders is that the pattern of behavior leads to disruption in normal social functioning due to the behaviors specific to the disorder. Compulsions are behavioral patterns associated with certain beliefs held by the individual with the disorder, whereas substance-use disorders refer more to the effects of the activation of the pleasure-seeking pathways in the brain when that behavior is engaged, through the use of "substances" such as alcohol or hard drugs.

Psychiatrist Charles O’Brien of the University of Pennsylvania attests that there is adequate brain imaging evidence to make a "pretty strong case that [gambling] activates the reward system in much the same way that a drug does" (935). Researchers in Germany have shown that gamblers show an increase in dopamine, stress hormones, and heart rate compared with non-gamblers. At Yale, brain imaging studies by a research group show that the brains of pathological gamblers resemble those of cocaine addicts – specifically, this shows a decrease in activation in regions that indicated judgment and motivation. This evidence collectively suggests that the
effects of being a "degenerate gambler" have about the same impact internally as being addicted to drugs or alcohol.

Behaviorally, we also see similar effects. Gamblers show impaired social functioning, as their behavior is geared toward feeding their attachment to gambling, much as the concerns of someone addicted to drugs are centered on being able to obtain their next fix. But what about other behavior? For instance, can people be "addicted" to things like sex, the Internet, or a certain genre of books? Here is where the fine distinction between addiction and compulsions comes into play. Like physical substances such as alcohol, behaviors are difficult to control because they could take other forms. If you refuse an alcoholic alcohol, he may turn to smoking instead. If someone is "addicted" to sex, their next recourse will take the form of increasing other pleasure-seeking areas in the brain in the same way that sex once did. It is the behavior of addiction itself that needs to be stopped for the obsession to engage in it to decrease. The compulsions are not addictions, but if the need for the addiction is removed, the compulsion may also decrease. Studies need to be conducted to ascertain the relationship between these factors (compulsion, obsession, and addiction) in behavior.

Blanketing addictive behavior into one DSM diagnosis may encompass a large group of people, but not be geared toward the needs of a specific person or group of people. It’s like a one-size-fits-all glove – it will fit most people’s hands generally well; there will always be outliers, and perhaps their issues are serious enough to warrant attention. But if their particular problems aren’t included in the DSM, how can they be treated fairly? The DSM committees need to recognize foremost that with the advance of technology and a deeper understanding of human behavior must come the acceptance that behavior will keep changing. The only thing to do is meet it – and when necessary, make it easier for people who need help with negative behavior patterns, to get it.

May the best man's sperm win

January 28th, 2010 by Bay McCulloch

One behavior that resonates throughout the animal kingdom is that males compete for female attention. Does this type of competition extend beyond the act of mating and persist at a cellular level? Research on deer mice done by Harvard biologist Heidi Fisher suggests that it does. When female deer mice go into heat they will frequently mate with more than one male, meaning that many sperm from different males will be vying for her one egg. Sperm have been found to cooperate with each other and clump together on the way to the egg because those sperm that clump have a better chance of survival than those that make the journey alone. Fisher wanted to know if sperm from different males would cooperate regardless of which male they came from or if sperm would only clump with other sperm from the same mouse.

To examine this question, Fisher dyed the sperm from two male mouses different colors (one green and the other red) and mixed them together in a petri dish and observed what happened. She found that sperm would conglomerate based on the mouse that they originated from, meaning that red sperm would more often than not clump with other red sperm and green sperm would clump with other green sperm. It is not known how sperm can differentiate between similar and dissimilar sperm, but it isn't too hard to understand why such behavior occurs. It all goes back to our selfish genes, the desire to pass one's genetic material on to the next generation, an impulse so strong that even sperm will compete for this privilege.

Voter Apathy: Blame mom and dad

January 22nd, 2010 by Jenny X. Chen

In the dramatic days following the Republican’s senate-race victory in Massachusetts, politicians have been startled into the reminder that victory is always hard to guarantee. A common nightmare is voter apathy – that terrible high school dream where you’re the most popular kid at school but all your friends forget to vote.

While pundits will talk about vague platforms, poor campaigning and finger-pointing as root causes of voter apathy, science suggests alternative explanations. Investigators James H. Fowler (who collaborates prominently with popular Pfoho housemaster Professor Nicholas Christakis) and Christopher Dawes recently showed in 2008 in two independent studies of fraternal and identical twins that voter turnout may be genetically linked and inheritable.

The reasoning, as in most twin studies, was that if voter apathy were inheritable, then identical twins should have more similar patterns of voting or abstaining than fraternal twins. Examining data from the National Longitudinal Study of Adolescent Health, investigators were able to estimate that genetics dictates some 72 percent of differences in voting turnout. Futhermore, roughly 60 percent of differences in other political activity can be explained by genetic makeup. Other geneticists like Dr. Robert Polmin of Kings College, London, suggest that while the association may be true, the percentages concluded may be too high.

Naturally, each of the scientists concede that the remaining percentages that influence whether a person chooses to vote are gained from environmental cues, suggesting that although politicians may tremble at the idea that voter apathy is genetically engrained, there is still hope for behavioral changes caused by inspiring speeches and attractive ads.

In other words, don’t give up Dems. Just because you did it once doesn’t mean you’re allowed to sit back and expect voters to flock.

Stockholm Syndrome - "A Primitive Gratitude for the Gift of Life"

January 11th, 2010 by Colleen Berryessa

In California, the case of Jaycee Lee Dugard became front-page news in 2009, and the trial of her kidnappers will take place in 2010. Dugard was kidnapped, raped and held captive for 18 years by Phillip Garrido. Over the years, Dugard had many chances to escape or to get help, so many have asked, why didn't she? This response by prisoners is common, as exhibited by the many captives seen in this recent Time article, and is explained as something called Stockholm Syndrome.

When first interviewed by parole officers who were suspicious of her abductor, Jaycee Lee Dugard did not reveal her identity. Instead, she told investigators she was a battered wife from Minnesota who was hiding from her abusive husband, and described Garrido as a "great person" who was "good with her kids." Why would Dugard say these things, even in safe custody of law enforcement?

Stockholm Syndrome is a psychological change that occurs in captives when they are seriously in danger, but are shown acts of kindheartedness by their captors. Captives who exhibit Stockholm Syndrome tend to empathize with and think well and positively of their captors. Such captives fail to identify that their captors' choices are in effect self-serving to only the captors, because the captives are being held against their will. When subjected to prolonged imprisonment, these captives can develop a strong relationship with their captors, in some cases including a mutual sexual interest.

According to the psychoanalytic view of this syndrome, this propensity might be the consequence of employing the strategy evolved by newborn babies to form an emotional connection to the closest authoritative figure in order to increase the likelihood that this adult will facilitate for the survival of the child, if not also prove to be a solid parental figure. In the Dugard case, Garrido seemed to fill that role for her, and therefore, was able to make her trust him for 18 long years.

Sleep on it!

January 9th, 2010 by Angela Yuen

During this January term at Harvard, most of us (hopefully) are catching up on all the missed sleep of this past semester and enjoying a period of rejuvenation and rest untroubled by thoughts of upcoming midterms and finals.  As the beginning of second semester looms ever closer, however, most of us are also mentally preparing ourselves for another period of sleep deprivation and cramming on Sunday nights to come.

But perhaps there is a way to cram facts into our head while we sleep, according to a recent study by Rudoy et al of Northwestern University.

The researchers performed a series of tests in which after subjects were taught the locations of certain pictures on the screen, they napped for 90 minutes while sounds related to certain pictures were played. The results showed that all subjects were able to recall the locations of those specific pictures much more efficiently than the pictures not reinforced by sound during sleep.  This would make sense, considering that it is speculated that memory consolidation occurs during sleep and rehearsal is known to be a good way to strengthen specific memories rather it be facts, names, or dates.

Looks like learning a fifth foreign language over J-term with those 1000 phrases on CD playing while you sleep may be an option after all!
And as for next semester, consider recording lectures and sleeping with headphones on – this may very well be the secret to the easy A that you’ve been missing all along! ;)

Submit to The Harvard Brain's academic section!

January 6th, 2010

Written a paper for class on mental health, neuroscience, or human thought and behavior? Want to see it published? The author of the best submission will win $75. Submissions to harvardbrain@gmail.com accepted through January 30, 2010.

Asides

IQ v. Intelligence

If George Bush is so smart (IQ 120), why is he so stupid?   Intelligence quotient (IQ)  tests claim to measure intelligence, but is there more to critical thinking than raw reasoning ability? Michael Bond in New Scientist:  Think of our minds as searchlights. IQ measures the brightness of the searchlight, but where we point it also matters.

Through the Looking Glass

MIT Technology Review has a set of stunning images of the brain. The slideshow traces the ways we have visualized neurons from Santiago Ramón y Cajal's 19th century sketches to Brainbow to MRI. To find out more about how some of these techniques work, check out "Project BrainSTORM" in our last issue.

Dopamine? Dope!

The same week the New York Times ran Natalie Angier's excellent article on dopamine neurons, we discussed Nature papers on dopamine in my neurobiology class. Classically, the neurotransmitter dopamine has been associated with pleasure and reward, but recent research suggests that dopamine neuron firing is more closely related to drive and motivation. Is this a real difference, or as one student asked, is this just a matter of semantics? Quipped another,  "Just look at half the kids at Harvard — they’re driven but far from happy." Yikes, maybe.

What happens when you put a dead salmon in a fMRI machine?

A lot, surprisingly. Dead salmon can evaluate the emotional content of photographs. Or not....a cautionary tale of using the right statistic tools in fMRI, which has got quite a bit of voodoo heat recently. Prefrontal.org has the whole story. We promise it's the funniest science poster you'll read all year.

Spring 2009 Issue Release

We've published our new Spring 2009 issue! Check out our new featured articles, and flip through our interactive online issue!

Bioethics at Harvard

The National Undergraduate Bioethics Conference is coming to Harvard March 13–14, and The Harvard Brain is a proud sponsor! The Harvard Undergraduate Bioethics Society hosts the conference this year and they have a lot of interesting lectures and discussions lined up. For more information, please see http://www.hcs.harvard.edu/bioethics/nubc2009. There will sure to be plenty of food for thought to hold you over until the 2009 Brain comes out at the end of April!

Welcome to our new site!

We hope you enjoy it! On the left side of our homepage, you can read some featured articles from last year's issue of The Harvard Brain. To read the full edition, please see the archives page. Stay tuned for the 2009 edition, debuting at the end of April. We have many exciting features planned, including an interview with Will Wright, creator of The Sims and Spore, a book review of Prof. Wrangham's latest book How Cooking Made Us Human, and an article by renowned bioethicist and Princeton Professor Peter Singer.