Neuro_________
Neuroscience has transformed itself into a highly interdisciplinary science rooted in biology that integrates psychology, chemistry, physics, computer science, philosophy, math, engineering, and just about every other type of science that we know of. Botany? Synthesis of new drugs. Oceanography? Animal models. I’m sure there must be some science that neuroscience hasn’t touched, but I can’t think of one.
Since its inception, neuroscience has gotten its grubby little fingers all over the science community. Now, it’s not clear whether the recent flood into even more fields is the result of ambitious forward thinkers or crafty businessmen, but either way, “neuro” as a prefix is popping up everywhere. While some of these up-and-coming fields show promise or, at least, raise interesting questions, others are less convincing…
Neuromarketing: Studies consumers’ sensorimotor, cognitive, and affective response to marketing stimuli
How: fMRI, EEG, eye tracking and GSR (Galvanic Skin Response)
Why: Provides information on what a consumer reacts to. (For example, is it the color, sound, or feel or a product that drew you to it?)
Does it hold water? The neuromarketing firms say so, but there’s minimal peer-reviewed published data to support their claims
Neuroeconomics: Studies decision making under risk and uncertainty, inter-temporal choices (decision that have costs and benefits over time), and social decision making
How: fMRI, PET, EEG, MEG, recordings of ERP and neurotransmitter concentrations, in addition to behavioral data over various design parameters
Why: Some facets of economic behaviors are not completely explained by mainstream economics (expected utility, rational agents) or behavioral economics (heuristics, framing)
Does it hold water? The field has emerged as a respectable one, with centers for neuroeconomic study at many highly regarded universities
Neurolaw: Integrates neuroscientific data with the proceedings of the legal system
How: MRI, fMRI, PET
Why: Supporters believe reliable neuroscientific data can elucidate the truth behind human actions
Does it hold water? TBD. Lie detectors and predictive measures are not yet refined enough to make any real claims. However, the insanity defense (in which a defendant can claim that a neurological illness robbed him or her of the capacity to control his or her behavior) can clear defendants of criminal liability. In addition, the ethics of sentencing and lawmaking with neuroscientific data falls in a grey area.
Neuropolitics: Studies the neurological effects of political messages as well as the characteristics of political people
How: fMRI, GSR
Why: To asses the physical effect of political messages . Also, are liberals and conservatives mechanically different?
Does it hold water? Probably not, but everyone likes a little neuro-babble.
I’m sure this is only the beginning of the neuro______ revolution.
Brain Scans as Mind Readers? Don’t Believe the Hype. – Wired.com
The Brain on the Stand – NYTimes.com
Why is every neuropundit such a raging liberal? – Slate.com
Neuroeconomics – Wikipedia
Neuromarketing – Wikipedia
Music to my Ears?… Just Kidding
It was an average Wednesday night at 8, and I was channel surfing. As I changed the channels I heard singing; I knew instantly that the show was American Idol. Most of you watch or have watched the show in the past and time and time again it befuddles me to think how these individuals think that they can sing. Most of the singers not only have piercing voices, but they are off key and sound terrible. After most auditions, the contestants - although I know it was horrible - still believe their rendition of a Whitney Houston song was outstanding. If you are like me then you want to know why.
Tone-deaf individuals do not have brain damage or trouble hearing, and they are definitely not suffering from a lack of exposure to music. So what actually makes people unable to understand their inability to sing? Researchers conducted an experiment that tested the connectivity of the arcuate fasciculus (AF), which connects the temporoparietal junction (the place where the temporal and parietal lobes meet), with the frontal cortex in the brain. This junction allows neural substrates of sound perception and production to be connected. The researchers hypothesized that there are structural and functional abnormalities that contribute to tone deafness.
To test their hypothesis, structural MRIs with diffusion tensor imaging (DTI) were performed on the patients. DTI is a type of MRI that allows researchers to map internal structures with the diffusion of water. After processing the information, the maps identified that the right superior AF was diminished compared to control, signifying that the AF is disrupted in tone-deaf individuals. Also, resultant fibers in tone-deaf individuals projected dorsally toward the parietal lobe and/or translocally to the left hemisphere and not toward the ipsilateral inferior frontal gyrus where normal individuals have projections.The imaging and testing of the AF led researchers to conclude that the superior branch is responsible for fine-grained discrimination, and the inferior branch is responsible for automatic matching of sound output to its target. They also tested the volume of the fibers connecting each part of the brain and discovered that tone-deaf individuals have a lower volume of fibers than the control, which is important for conscious pitch determination and the degree of action-perception mismatch. According to the experiment, both the superior and inferior branches of the AF are needed for accurate perception and production.
Figure 1: A comparison between the regions of interest of the posterior superior temporal gyrus (pSTG) and the posterior inferior frontal gyrus (pIFG) of the right side of the brain
Tone-deafness is a new disconnection syndrome that deals with impaired pitch perception and vocal sound projection. There are no known genes that are associated with this condition that affects the AF fibers and their connection between the superior and inferior areas of the brain. So for all of you non-tone-deaf American Idol viewers, you will just have to sit through the next episode and know that most of singers cannot help but obliviously sing off-key.
Other Reading of Interest:
Tone Deafness - Scientific American
The amusic brain - BRAIN: A Journal of Neurology
Lasers: The Key to Mind Control?
The ColBeRT DMD (digital micromirror device)
As a neuroscientist, one typically becomes accustomed to thinking outside of the “box.” After all, the brain is incredibly complex and cryptic, and some creative thought is required to develop methods to uncover its secrets.
Francis Crick advised that the greatest hurdle standing in the way of neuroscience is the inability to specifically stimulate a single neuron without altering any of its surrounding cells. This daunting task appears to be a thing of fantasy when considering the innumerable intricate connections the brain is composed of. However, Harvard University’s Samuel Lab has made a reality out of a dream with their groundbreaking research involving transgenic C. elegans. Recently published in Nature, the research of Dr. Andrew M Leifer and his team utilizes a manipulatory optogentics technique called ColBeRT to control the nervous system of a worm with the light from a laser.
Optogenetics is the methodology of employing genetics and visible light to manipulate the activity of living cells. In order for optogenetics to be applicable in the laboratory, the insertion of opsin genes, which encode for light sensitive proteins, into an organism’s genome is necessary. The activity of the resulting opsin-containing cells can be regulated by exposure to visible light. Relative to the work of Leifer et al., optogenetics provides a platform by which the genetically altered motor and sensory neurons of C. elegans can be controlled with the use of a precise laser. Why use C. elegans? According to Leifer et al., “the nematode C. elegans is particularly amenable to optogenetics owing to its optical transparency, compact nervous system and ease of genetic manipulation.”
A schematic of the ColBeRT technique
The ColBeRT (Controlling Locomotion and Behavior in Real-Time) technique, which was designed for the optogenetics research being done at The Samuel Lab, provides a way to specifically track a worm’s movement. A video camera with real-time feedback follows an illuminated and moving C. elegans under a dark field. The worm is placed on a motorized stage, which keeps the image of the organism centered in the camera’s view. Once the worm’s movement is recognized and registered by a specialized graphical user interface (GUI) software called MindControl, the image of the C. elegans is processed and the worm’s image is divided into 100 evenly spaced segments. From these segmented portions, specific target cells can be chosen, the locations of which are transferred to a DMD (digital micromirror device). This pattern is then projected onto the worm by the DMD, allowing for the illumination of the targeted points with a laser. This laser can precisely pinpoint the location of a specific target cell by a simple algorithm specifically designed for the movement analysis of C. elegans.
The impressive spatial and temporal resolution (~50 frames per second) of the ColBeRT technique makes the system scientifically applicable and valid. The ColBeRT’s spatial resolution of ~30ms allowed Leifer et al. to utilize the technique for a number of manipulatory actions on their transgenic nematodes. When cholinergic motor neurons of transgenic C. elegans were exposed to laser light, forward motor movement was suppressed and either paralysis or backward movement of the worm was propagated. Similarily, single touch receptors of the worms were also genetically modified to be sensitive to light. In a normal worm, a gentle touch will stimulate these receptors, causing the worm to repel in the opposite direction of movement. In transgenic C. elegans, illuminating these specific receptors with the light from a laser was able to affect the direction of the worm’s movement, just as a physical stimulus would have. Even more astounding, HSNs (hermaphrodite specific neurons), which innervate the vulval region of C. elegans, were also able to be genetically modified and stimulated with light exposure. When a thin laser strip was shone on the HSN region of the worms, involuntary egg-laying was evoked.
Although still in its beginning stages, the ColBeRT technique seems to be a promising solution to overcoming one of the primary difficulties standing in the way of neuroscience. ColBeRT not only highlights cell-to-cell interactions, but also identifies the precise actions of specific neurons, something that had never been thought possible in the past. As technology develops further, perhaps we will soon be able to manipulate the cells of more complex organisms and eventually, even mammals. Optogenetics and techniques like ColBeRT may be the key to discovering the subtleties of different neurons and could even potentially help map out the human brain.
Single Worm Neurons Remotely Controlled with Lasers - Scientific American
Optogenetic manipulation of neural activity in freely moving Caenorhabditis elegans - Nature Methods
The Samuel Lab videos - Vimeo
F—— Magnets, How Do They Work?
It has been said “The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'” (Isaac Asimov), and a recent observation by a Harvard Medical School lab studying the brain chemistry of Bipolar Disorder has researchers uttering that precise phrase...as well as the one alluded to in the title of this post.
The initial study prompting such observations recruited patients suffering specifically from Bipolar Disorder, also known as Manic-Depression, for 20-minute brain scans in an MRI. MRI scans subject patients to a harmless magnetic field and pulses of radio waves to create detailed structural images of various body parts, in this case, the brain. While the procedure is painless and relatively short, it can be unpleasant for reasons wholly unrelated to the magnets and radio signals; patients frequently report unrelated bodily discomfort or claustrophobia. For this reason it was all the more surprising, according to one researcher, that patients participating in the study started to report mood elevations (that for some lasted days or even a week) following the scan. One patient even subtly suggested that the researchers had slipped her something without her permission.
Patient undergoing TMS treatment for depression
The use of magnets to improve the effects of depression is not uncharted territory in neuroscience and it might even sound familiar to some. Transcranial magnetic stimulation, or TMS, is another technique that has recently been adapted to depression therapy, yet it is more akin to electroconvulsive, or “electroshock”, therapy (ECT) than MRI.
TMS uses a magnetic field to induce a relatively small electric current, without causing seizure or loss of consciousness, to stimulate the left prefrontal cortex, the area thought to be under-active in depression. Whereas ECT treatments are utilized only in the most extreme depression cases because of the risk of seizure and necessity of sedation, TMS carries much fewer risks and can be used for more mild depression. While the exact mechanisms are still not known, particularly the roll of seizure for the antidepressant effects, both ECT and TMS have been cleared by the FDA.
But the magnet employed in MRI does not excite specific brain regions (if it did the entire imaging method of functional magnetic resonance imaging, fMRI, would be ineffective) and it is certainly not strong enough to induce seizures. After observing the curious side-effects of their initial study, the aforementioned researchers set up a small preliminary study with both bipolar and normal controls who confirmed respectively that the effects were not placebo, and that even those without depression can experience the mood-boosting effects of MRI.
So could a new depression treatment soon be joining the ranks of such accidental scientific breakthroughs as penicillin and Post-It notes? At this point it really is unclear. The actual mechanism of the mood-boosting effects of MRI on depressed patients is not yet understood, nor have the effects been generalized to unipolar depression. However, the safety of exposure to MRI has been confirmed by the FDA and a lack of total understanding regarding what causes the “miraculous” effects of that other magnet-based depression treatment, TMS, as well as a host of other medical treatments (including lithium for Bipolar Disorder) certainly has not prevented their use.
Picture Unrelated
Jazz in an fMRI? An Innovative Look at Creativity and the Brain
We’ve all been exposed to jazz at one time or another—whether it be the musings of an accomplished jazz pianist or the improvisational skills of a saxophone player, jazz is something that’s familiar to us. But, when enjoying such a piece of music, we may not have considered the effect it has on the musician’s brain.
Charles Limb, musician and researcher at Johns Hopkins University, is specifically interested in the workings of the brain during musical improvisation. In order to better understand these mechanisms, he studied the brains of accomplished jazz musicians playing music in an fMRI machine.
The two pillars of his study—playing music which has been memorized and over-learned, and playing music which has been entirely improvised—were designed to pinpoint which brain regions were most active in each situation, as well as to see how differing amounts of creativity play a role in brain activity. Limb asked participants to first play a memorized piece of music on a specially designed keyboard, and then to improvise based on the scale progression of the previous piece.
What he found was quite interesting.
In the studies, Limb observed that, compared to the fMRI of brains playing memorized music, those playing improvised music typically had a higher amount of activation in the medial prefrontal cortex, an area attributed to self-expression, and a lower amount of activation in the lateral prefrontal cortex, an area attributed to self-monitoring. He postulates that in order for an individual to be creative, they must exhibit a sort of dissociation in the frontal lobe by which the large part of the brain controlling self-monitoring is not inhibiting self-expression of new, free-flowing ideas.
More recently, Limb has been studying another form of improvisational music, which he believes serves a similar social function to that of jazz—hip-hop. To do this, he has recruited the talents of accomplished hip-hop artists from the Baltimore hip-hop scene and studied their brain activity while they rap. The structure of the study is similar to that of the jazz pianists in that it was separated into two parts—one to study brain activity while performing a memorized piece and one to study brain activity while improvising. The participants were asked first to rap a piece written by Limb (which they had not seen before), and then to improvise based on a guideline of periodically prompted words. Though the study is not yet complete and no conclusive results are available, what Limb has seen so far has been quite promising.
Outside of Limb's unique research, no extensive work has been done yet to study these phenomena. However, these results prove to be very promising in that they can offer new ways to think about creativity and the brain. Perhaps sometime in the future, with more sophisticated methods of brain imaging, it will be possible to understand the workings of the brain in other creative realms, such as dance. These and many other questions are coming closer to having answers.
Charles Limb: Your Brain on Improv - Video on TED.com
TED Blog - Hip-hop, creativity and the brain: Q&A with Dr. Charles Limb
Connectomics is the name. Connections are the game.
You are unique, just like everyone else.
Connectomics is the study of the structural and functional connections among brain cells; its product is the "connectome," a detailed map of those connections. The idea is that such information will be monumental in our understanding of the healthy and diseased brain. Sebastian Seung thinks that a complete connectome of the human brain will be one of the great prizes in 21st-century neuroscience.
Efforts to construct brain connectomes are split into two categories: ones that use imaging techniques like MRI, PET, and DT, thus focusing on macroscopic connections or tracts; and those that use electron microscopy to map the tinniest of axons (0.2-20 microns in diameter) and individual synapses.
While this may sound daunting, it also seems the obvious thing to do in order to really understand how the brain works. After all, don’t all our memories, personalities, and behaviors dependent on the structure of the brain, down to the microscopic level? So why is connectomics so new? Because the three-pound enigma that can contemplate all things big and small – from protons and electrons, to planets and stars, to galaxies and the whole universe – contains more parts than anything we’ve ever studied before. The human brain, we’ve been told, holds 100 billion neurons, with close to one quadrillion synaptic connections total; storing all of that information in one brain would take one Exabyte of data (that’s one trillion Gigabytes).
Jeff Lichtman and colleages at Harvard remain hopeful. They are developing novel tools to automate the tedious task of scanning brain slices. They expect the connectome to reveal differences in the way healthy and diseased brains are wired.
The effort is laudable, considering its scope and ambition, but it begs the question: does all behavior, experience, perception, etc depend on the structure of synapses and connectivity of neurons? More pointedly, does structure determine all function – chemical and electrical? Sure, larger synapses or more dendritic spines make stronger connections and more efficient transmission of information, but a snap-shot connectome won’t take into account temporal dynamics and enzymatic processes, which play a big role in the active brain.
In his TED talk, Sebastian Seung says that to test the hypothesis that “I am my connectome,” we could try to read out memories from someone’s connectome. But memories are not just synaptic connections – they are also assemblies of neurons in time or firing sequence. The connectome does not take those into account. And Seung fails to explain how we could actually verify any of those personal memories, since current methods of constructing a connectome involve cutting the brain into thousands of 30-micron slices.
If we could devise some non-invasive methods to construct a human connectome at the synapse level, what ethical issues would we face? Could a personal connectome be the ultimate breach of privacy? Could it redefine or “undefine” what we consider to be normal brains/mental states?
Constructing a comprehensive human connectome is a great challenge. A bigger challenge would be to model the electrical dynamics of the 100 billion human neurons. But perhaps the most important quest for neuroscience isn’t building a connectome, but learning how neuronal activity creates experience.
Neurocartography - Narayanan Kasthuri and Jeff Lichtman via NIH Public Access
Sebastian Seung: I am my connectome - TED.com
Seeking the Connectome, a Mental Map, Slice by Slice - NYTimes.com
The Science Behind Appetite
“We were hardwired to eat and eat—and particularly to eat fatty foods because we didn’t get them often,” says Sharman Russell, author of Hunger: An Unnatural History. So if you’re among the 200 million Americans who have surpassed their target weight, don’t feel so bad. Somewhere in your brain, there is a circuit for food.
While eating is vital to life, it’s a voluntary action. But nature has made eating irresistible. So what is the science behind this irresistibility? Over the course of a year, the average adult male consumes about 900,000 calories, yet his weight doesn’t fluctuate by more than a pound. It takes a lot of effort from your internal systems to keep this balance, and an important substance behind this is a hormone called ghrelin.
Ghrelin, identified in 1999, is produced in the gut in response to meal schedules. Its purpose is to give the empty feeling we know as the need to eat. When ghrelin hits the brain, it affects three specific areas: the hindbrain, the hypothalamus, and the mesolimbic reward center. The hindbrain controls the body’s automatic and unconscious processes. It is responsible for the sensation of hunger. For the purposes of eating and digesting, the hypothalamus governs the rates of metabolism. And at the center of the midbrain lies the mesolimbic reward center, where the feelings of pleasure and satisfaction are processed. This is what motivates us to eat and keep eating.
Of course, other substances in our body govern our appetite as well as ghrelin. Even as ghrelin continues to arouse our appetite, other systems are standing by to slow down the process. The most basic such step occurs in the stomach and intestines. Distension sends a signal to the brain to stop eating. That message is then reinforced by a peptide called cholecystokinin (CCK) and two hormones called PYY and GLP-1. They all send complex chemical messages that literally tell the brain to stop eating. And, in the case that food consumption continues, the body has a last resort appetite-supressing hormone called leptin. Discovered in 1994, leptin affects the hypothalamus where it inhibits a pair of neuropeptides known to stimulate appetite.
So with all these measures in place to stop the body from eating, why do we overeat? Studies have shown that ghrelin hits the mesolimbic reward region very powerfully. It has been shown that this part of obese people’s brains activate very similarly to how the brains of drug addicts activate when exposed to their preferred substance. While the causes of over eating are very obvious, the real question is: how can we control it? Diet and exercise are often the recommendations (and should be followed), but the minds who discovered leptin, ghrelin, and all the other appetite-related peptides and hormones are also looking for ways to harness the power so we can take better control of it on our own.
Hunger: An Unnatural History - Sharman Russell
Beefing Up Your Brain
"Dude, my action potentials are on fire right now."
- Are you aging and senile?
- Do you find yourself frequently forgetting facts and misplacing objects?
- Are you simply dissatisfied with your cognitive strength?
The Posit Science Brain Fitness Program might be right for you!
As we age, our brains age with us, slowly deteriorating over time. For the fast-paced lives we now lead however, having mediocre cognitive abilities just doesn’t cut it. Famed neuroscientist, brain-plasticity connoisseur, and new businessman Michael Merzenich has engineered a series of “brain fitness” activities that are claimed to help individuals keep their minds in tip-top shape.
Merzenich’s Posit Science program is based on neuroplasticity, the ability of the brain to reorganize itself. While cortical reorganization is a remarkable asset of the brain to adapt to change, it may also be detrimental when the brain is not utilized to its full potential. Dr. Merzenich asserts that in order to maintain neurological skill throughout adulthood, individuals must continue to train the various cognitive-sensory facets of the mind.
The clinically supported Posit Science program offers a multi-modal, total brain training package composed of both an auditory skill and a visual skill program. This training includes a series of six computer-based programs specifically designed to improve the brain’s auditory-visual processing and perceptive abilities.
Currently, Posit Science is looking to broaden the applicability of its products by venturing into the world of social networking. The company has recently developed and launched a networking site called “Brain Odyssey,” through which individuals can work together to solve mysteries and virtually explore cities throughout the world, all while collaborating on cognitive training tasks.
But Wait...!
In addition to offering a mental fitness program, the company website also features several brain games as well as a few “brain tests” as an informal way of testing one’s cognitive prowess, free of charge.
Click here to get your cognitive fitness on today!
A "better brains" collective launches to improve cognition of the masses - Scientific American
Dog Lovers, Rejoice!
Any dog lovers out there? Have you ever wanted to refute someone who claimed "dogs can't really understand you?" PBS program Dogs Decoded: NOVA asserts the idea that dogs are able to communicate with and understand humans better than any other animal that we know of.
When humans express an emotion, the right and left sides of their face show very different pictures. The right half is more expressive than the left when displaying all emotions, from happiness to anger to guilt. Therefore, humans have developed something called a “natural left gaze.” This means whenever we are presented with a face, we automatically look to our left to view the right side of their face to see a better display of their emotion. Recent studies with dogs have shown that they use this same mechanism when presented with a human’s face. Yet, when presented with a picture of another dog’s face, Fido treats it as if it is a picture of an object and randomly assesses the picture with no determined natural gaze. Dogs are the only animals known to display a natural left gaze when presented with a human face, suggesting that they have evolved to understand our facial expressions. Scientists are becoming more convinced that dogs are able to interpret our emotions better than many people think.
There are a few unique communication tools that only humans possess, such as eye gaze. Humans have almond-shaped eyes with white sclera surrounding the pupil so others are able to follow the direction of one’s gaze. We also use pointing as another communication tool that many other species are not able to utilize or comprehend. Cognitive psychologist Dr. Juliane Kaminski has been performing experiments with both chimps and dogs studying these two communication tactics. When a chimp is presented with two cups upside down and Kaminski points at the cup containing a reinforcer (such as a food treat), the chimp is not able follow her point nor gaze to pick up the correct cup. Instead, Kaminski notes that chimps tend to make a decision before she even points, supporting the idea that they are not wired to comprehend human gestures. Yet Kaminski performs this same task with dogs and they are able to follow to where her finger is pointing and retrieve a reinforcer. Even when presented with only a gaze at the correct cup, dogs are often able to determine which one Kaminski is urging them to choose.
It’s interesting to think that dogs have evolved to advance the way they communicate with the species that has domesticated them.
Dogs Decoded: Nova - PBS special via Netflix
The Dangers of Thinking on Auto-Pilot
Dependence on a GPS causes you to ignore external stimuli needed to build cognitive maps
The Global Positioning System (GPS) has revolutionized the way we travel. We are able to “find ourselves” when we get lost and also get directions to anywhere we want to go. However, a recent study suggests that depending too heavily on a GPS can have a negative effect on your brain.
Researchers at McGill University conducted three studies that confirm that there is a link between being an avid GPS user and having difficulty in memory-related tasks. Instead of using spatial-navigation strategies consisting of building cognitive maps to know where you’re going, GPS users may depend on a stimulus-response strategy which determines where to turn based on repetition instead of any external stimulus.
The fMRI images of younger subjects who used the spatial-navigation strategy when compared to older subjects who preferred the stimulus-response strategy when navigating through a virtual maze showed to have increased activity in the hippocampus, the structure in the brain responsible for memory and spatial navigation. Moreover, older adults that preferred spatial-navigation strategies had more gray matter in their hippocampal region than those who preferred the stimulus-response strategy. They also scored higher on standardized cognition tests.
The Hippocampus is the region in the brain responsible for memory and navigation
Although these tests do not confirm causality, it is very possible that the lack of hippocampal activity in the brains of GPS users may lead to atrophy of the hippocampus as they age, which puts them at greater risk for diseases such as Alzheimer’s. The researchers do not suggest getting rid of the GPS all together. However, they recommend that although it might be necessary when going to a new place, it wouldn’t hurt to turn your GPS off in a familiar neighborhood. Although building a cognitive map may take some time, it is well worth it.
GPS addict? It may be eroding your brain - Mental Health on MSNBC
Study: GPS Units Cause Memory and Spatial Problems - Daily Tech
