Category: News
Large Scale Neuronal Network Simulations Take Off
Google, IBM, Microsoft, Baidu, NEC and others use deep learning and neural networks in development of their most recent speech recognition and image analysis systems. Neural networks have countless other uses, so naturally there are tons of startups trying to use neural networks in new ways. The problem being faced with now, is how exactly to implement neural network models in a way that mimics the circuitry of the brain. Brains are highly parallel and extremely efficient; the ultimate achievement of a neural network model would be able to perform large scale parallel operations while being energy efficient. Current technology is not well suited for large-scale parallel processing, and it is nowhere near as efficient as our brain, which uses only 20 watts of power on average (a typical supercomputer uses somewhere along the order of several megawatts of electricity).
One way in which future computers could mimic the efficiency of the brain is being developed by IBM. IBM believes that energy efficiency is what will guide the next generation of computers, not raw processing power. Current silicon chips have been doubling in power through Moore’s Law for almost half a century, but are now reaching a physical limit. To break through this limit, researchers at IBM’s Zurich lab headed by Dr. Patrick Ruch and Dr. Bruno Michel want to mimic biology’s allometric scaling for new “bionic” computing. Allometric scaling is when an animal’s metabolic power increases with its body size; the approach taken by IBM is to start with 3D computing architecture, with processors stacked and memory in between. In order to keep everything running without overheating, this biologically-inspired computer would be powered, and cooled, by so-called electronic blood. Hopefully this fluid will be able to multi-task, and like blood supplies sugar while taking away heat, accomplish liquid fueling and cooling at the same time.
Could There Eventually be a Cure for Huntington’s Disease?
Huntington's disease causes widespread deterioration of brain tissue (left), particularly of the structures in the Striatum which is located in the center of the brain.
Huntington's disease, a neuro-degenerative disorder, affects roughly 5-10 out of every 100,000 people. The disease acts by deteriorating many structures in the brain, beginning with the Caudate Nucleus, which is involved in motor control. By the end of their lives, patients are expected to lose about 30% of their brain mass.
In the last few decades much has been learned about the disease: we now know that it's genetic, caused by a mutation on the 4th chromosome, and leads the 'so-called' huntingtin protein to grow too long and fold in on itself incorrectly. Parents with Huntington's disease each have a 50% chance of passing it on to their child. Symptoms usually appear between 35 and 45 years of age, and the life expectancy after the first appearance of symptoms is 10-20 years. There currently is no treatment for Huntington's itself, so patients can only receive a little bit of relief from their symptoms while the disease progresses.
So far, there is no real consensus among scientists about how exactly the disease works, but it's generally agreed that it all starts with the mutated huntingtin protein. What if that protein was somehow changed or blocked? This idea prompted some experimentation by Holly Kordasiewicz and her colleagues.
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Research Spotlight on Nobel Laureate Thomas C. Südhof
Thomas C. Südhof
For those interested in scientific research, the Nobel Prize is an esteemed award, recognizing one’s work and dedication. However, many student researchers are often disillusioned about the kind of work that is put in to receive such high praise. More often than not, these individuals did not suddenly discover something new. To be sure, their findings are the fruits of years of research and passion in the field of science. As a great model of dedication, recent Nobel laureate Thomas Südhof provided incredible insight to our understanding of the human brain communication. But, once again, his work was in the basic-science field, on a topic which, in fact, we learn about in our introductory neuroscience courses. In this brief article, I will outline the most recent findings from Dr. Südhof’s lab in hopes of showing aspiring researchers that continued diligence and passion for learning is most important.
Neurons communicate with each other by a signaling process mediated by what is known as action potentials. Changes in concentration and electrical gradients cause the action potentials to fire down the neuron, until it reaches the synaptic bouton. It is here that one neuron forms a synapse with another neuron. The synapse is the site at which communication is happening. But, for the most part, two neurons are not physically connected, so how does communication happen? In a process called neurotransmission, when the action potential reaches the end of the neuron, an influx of Ca2+ ions cause vesicles to release certain chemicals out of the neuron, as a signal to the next. These vesicles are like little packets of neurotransmitter chemicals. Herein lies the question that Dr. Südhof sought to illuminate: mechanistically, how do these vesicles actually release the chemicals?
The Effects of Stress on Memory Loss
Stressed out? You may be at a higher risk for Alzheimer's disease. You're probably wondering to yourself how that is possible. Highly intelligent people who use their brains all of the time, like scientists, CEOs, and presidents, deal with stress on a day to day basis. The truth is that lack of higher education or brain activity is not the only major cause of dementia.
If keeping your brain active is a good way to prevent cognitive decline, then why did people such as Ronald Reagan and Norman Rockwell develop Alzheimer’s disease? The answer is stress. Recent studies have shown that people who deal with high levels of stress in their career or their family life are more likely to develop dementia. Stress cannot be said to directly cause dementia, but it is a trigger for the degenerative process in the brain.
An Argentine research team examined 118 patients with Alzheimer’s disease and 81 healthy individuals whose age, gender, and educational level were comparable to the Alzheimer's patients. Both groups were questioned about the amount of stress that they had faced in the past three years. The researchers reported that 72% of the Alzheimer’s patients admitted to coping with severe emotional stress or grief, such as the death of a loved one or financial problems. This was nearly three times as many as the control group.
Why Are People Sexist, Racist, and Judgmental? Behind Cognitive Bias and Prejudice
A man or a woman could be of above-average intelligence, well-educated in medicine and psychology, and understand that every statistical measurement of personality and temperament can be distributed across a bell-curve in a large enough population. He or she could comprehend the determining power of genetics, the impact of cultural influence on belief systems, and how neuroplasticity molds our mental processing to respond to environmental stimuli.
A clever, sophisticated professional could understand all of this, yet still believe that somehow, all members of the opposite sex are manipulative and irrational. Not some, all 3.5 billion of them. Why?
Perhaps throughout his or her life, this person has made irrational decisions to socialize with very irrational and emotional people of the opposite sex, and through these experiences has thus formed a gender bias. Research shows we tend to mostly place people into categories of gender, race, and age. This task is so pervasive that scientists have deemed it our “primitive” categorization.
Once we’ve made up our mind about a group, or even someone in particular (consciously or not), it’s often hard to change our opinion. When beliefs are formed, confirmation biases kick in and begin to look for information that supports our views, and selectively ignore everything which doesn't. Maybe someone had decided that you were shy and uptight when you first met. You were more reticent than usual because you had only gotten 3 hours of sleep the night before. Now that acquaintance may not notice all the times you’re friendly and outgoing, but instead seems to pounce on all the times you’re a little quiet.
Scientists Discover Gene Needed for ‘Memory Extinction’
Painful memories: a thing of the past?
What if you were able to erase all of your painful memories by simply taking a pill? While this might sound like something out of a sci-fi film, a recent study conducted by a group of researchers at MIT suggests that it may be possible in the future.
The researchers say that they’ve identified a gene known as Tet1 that appears to be important in the process of “memory extinction.” Memory extinction is the natural process of older memories being overridden by newer experiences. In this process, conditioned responses to stimuli can change: what once elicited a fearful response doesn’t always need to if the danger has ceased.
In the study, researchers compared normal mice to mice without the Tet1 gene. The researchers conditioned all of the mice to fear a particular cage where they received a mild shock. Once the memory was formed, the researchers then put the mice in the cage but did not shock them. After a while, mice with the Tet1 gene lost their fear of the cage as new memories replaced the old ones. However, mice lacking the Tet1 gene remained fearful.
Mothers Eating Their Babies? – No, It’s Not Cannibalism…
Spaghetti and Babies Anyone?
If you’ve ever seen someone with a baby, chances are you’ve heard them say something along the lines of “You’re so cute; I could just eat you up!”
Well a recent article published in Frontiers in Psychology by a research team at the Technische Universität of Dresden, Germany shows there may be a link between an infant’s smell and a female’s response, depending on the status of the female. Scientists have studied the connection between olfactory signals and the bond between a mother and her infant in several non-human mammal species. However, up until now, the research performed on mother-infant bonding in humans has only ever explored the visual and auditory senses.
What they did:
A total of 30 women were tested. Fifteen of the women had given birth for the first time three to six weeks prior to the experiment (primiparous). The other 15 women had never given birth (nulliparous). To obtain the sample odors, 18 infants each wore a T-shirt for two nights postpartum. The shirts were then placed in plastic bags and frozen to keep the odor unaltered. During the experiment, each woman was exposed to both “odorless” air and the odors of two different infants; primiparous women were never exposed to their own baby’s odor. The women were asked to rate the odor on intensity, familiarity, and pleasantness, though none of the participants were aware of what the odor stimulus was. As the women processed the different odors, an fMRI machine scanned their brain.
You Are Not My Mother!
Have you ever seen someone else’s doppelganger? That is, have you ever seen someone who looks exactly like a friend or family member, but is in fact just a random person? I am sure most of us have. Now, imagine that doppelganger you see is actually your mother, and it's your brain that's deceiving you. It could happen. In a strange and very rare syndrome called the Capgras Delusion, patients believe that someone close to them has been replaced by an impostor.
When your brain perceives something, it actually undergoes a rather long and complicated process of perception. The image is first seen on the retina, where it travels to the occipital and temporal lobes. Within the temporal lobe of the brain, the fusiform gyrus is responsible for facial recognition (it's known as the "face area" of the brain). Connections between the fusiform gyrus and amygdala, a structure usually associated with emotion, exchange the information and determine whether it is of emotional significance to the individual.
The Capgras Delusion is caused by damage to these connections. As the brain is no longer able to exchange information between the fusiform gyrus and the amygdala, the individual cannot assign an emotional importance to the sight of the person in front of them. In this case, the brain assumes that the person must be attempting to imitate their mother, as she looks eerily similar. There's just too many similarities between this person and someone you know, and your brain reacts in a rather unpleasant way.
It's a rather unfortunate syndrome, as it prevents the patient from assigning emotional significance to most things that they are able to see. However, the disorder is entirely visual: if a patient suffering from Capgras hears their mother or father (or other person close to them), they are able to easily conclude that it is actually their parent.
Imagine coming home to your parents. Except you don't recognize them as your parents, only that they're eerily similar to everything you know about your parents. They know your embarassing childhood stories, your scars, all your friends. Yet to you, they're completely a stranger, a perfect replica who is undecidedly not your parent. It's a pretty creepy thought.
-Roberto Barroso Luque
Further reading:
Ogden, J. (n.d.). Retrieved from http://www.psychologytoday.com/blog/trouble-in-mind/201208/the-capgras-delusion-you-are-not-my-wife
Ramachandran, V. (0). Retrieved from http://www.ted.com/talks/vilayanur_ramachandran_on_your_mind.html
Enriched Environments: Neuroscience Learns From Poverty
In the last century, treatment of social and learning disabilities has drastically changed. Through the Individuals with Disabilities Education Act, every student who qualifies for special education is entitled to a free and appropriate public education, delivered through an individualized education plan. An 'IEP' is designed through the collaboration of parents, teachers, and special education specialists. The largest category of learning disability is the specific learning disability, of which dyslexia is a typical example.
The amount of care put into special education has drastically changed the lives of many individuals, however, special education excludes those who have a learning disability due to economic situations. This reflects a longstanding social and educational belief that learning disabilities are innate, the result of genetic predisposition and not due to upbringing. The prevailing paradigm did not believe that upbringing could have a significant effect on the development on the brain.
To little surprise, neuroscience is showing otherwise.
Every Student is Entitled to a Free and Appropriate Public Education.
We have always known that acute incidents can have a significant effect on brain development and function (such as in the effects of repeated physical trauma on function), but recent research is suggesting that external factors during development, including many associated with poverty, can have significant, long-term effects. These factors include higher levels of environmental toxins, lower nutritional levels, and increased levels of parental neglect. Recent research suggests that external factors, including poverty, can have significant internal effects on the brain, including brain development and function. Poverty affects the development of the brain in multiple ways, including through poverty-associated factors such as higher environmental toxins, lower nutritional levels, and higher levels of parental neglect. However, the research of Gary Evans and Michelle Schamberg of Cornell University indicates that solely the added stress of low socioeconomic status is responsible for these effects.
Falling through the cracks: addiction revisted
Thanks for the crac-I mean cake!
High Price is the most recent book from Carl Hart about the underlying causes of drug addiction. The text, which is written as a combination of personal memoir and scientific review, uses the author's research to back the idea that the physiological basis of drug addiction isn’t so much to blame as the sociological conditions in which abusers find themselves. Dr.Hart is a professor of neuroscience at Columbia University, who, having seen the first-hand effects of crack-cocaine addiction in the lives of those around him throughout his childhood in Miami, dedicated his career to attempting to elicit the underlying causes of what he observed. What he found surprised even him.
Dr. Hart began as an undergraduate, doing research on rats self-administration of cocaine. Initially, he saw the rats dose themselves to death, unable to resist the drug’s allure. What he noticed, however, was that when rats had an ‘enriched’ environment, they were able to ignore the drug for other rich stimuli, namely the presence of a fellow rodent to play with, a wheel to run on, or tasty treats to snack on. He then applied this line of thought to human subjects. In Dr. Hart’s experiment, crack-cocaine users, who were not seeking rehabilitation, were recruited to live in a hospital setting where every day they were given a sample of the drug (the dose of which was varied day-to-day and unknown to the subjects), followed by the choice of a monetary reward (which they would collect at the end of the study) or the option to continue smoking crack. Contrary to the societal belief that in their desire for the drug, crack addicts are beyond rational thought, the subjects made predictable and logical decisions in their daily choice. When the initial dose was fairly small, the monetary reward was reliably chosen over continuing to use the drug. What Dr. Hart concluded from these results was that addicts, in the right setting, can weigh the prospect of using the drug equally with gaining benefits that are only rewarded further in the future. What he drew from that idea was that perhaps the evidence we see of drug addiction in our culture is more heavily influenced by the situations surrounding those people rather than the actual physiological basis itself.
