Friday, September 16, 2016

Highlights and new discoveries in Neuroscience (August 2016)

In the latest issue of this monthly digest series you can learn why we're so good at reading, how the minds of psychopaths differ, why it might be time to get your kid off the iPad, and much more.


The brain of a psychopath

Ever wondered what the brain of a psychopath looks like? So did apparently researchers from the Donders Institute and the Department of Psychiatry at Radboud University in the Netherlands, who recorded brain activity from 34 psychopathic individuals, 14 of which were convicted criminals, while they were performing a simple reward expectation task in an fMRI scanner.

The goal of the task was to react as fast as possible to a white dot shown on a display screen by pressing a button. The white dot was preceded by either a red or green square, which indicated whether subjects could win money on the current trial (green) or not (red). Subjects had to react within 500ms to the white dot in order to get a reward ("hit", else "miss"). After every hit, the required response window became 20ms shorter, so subjects had to stay on top of their game to continue making money. On the other hand, after every miss the response window increased by 10ms.

Task schematics: the upper row showing a reward and the lower row showing a non-reward hit trial (i.e. responses below a variable response limit).

What the researchers saw was that the reward center in the brains of people with many psychopathic traits (both criminal and non-criminal) were more strongly activated than those in people without psychopathic traits. This was already known for non-criminal individuals with psychopathic traits, but was now extended to individuals with a criminal record.

Another interesting difference was discovered between non-criminal people with multiple psychopathic traits and criminal people with psychopathic traits. "There is a difference in the communication between the reward center and an area in the middle of the forebrain", said Dirk Geurts, research in the Department of Psychiatry at Radboud. "Good communication between these areas would appear to be a condition for self-control. Our results seem to indicate that the tendency to commit an offence arises from a combination of a strong focus on reward and a lack of self-control. This is the first research project in which convicted criminals were actually examined."

The next relevant question would be: what causes these brain abnormalities? It is probably partly hereditary, but abuse and severe stress during formative years also play a significant role. Follow-up studies will provide more information.

Source via

Brain areas that distinguish between good and bad

When someone offends you while smiling, should your brain interpret it as a genuine smile or as an offense? Researchers at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig and the University of Haifa, Israel, have identified neural mechanisms that help us understand whether a difficult social situation is emotionally positive or negative. To do this, they showed emotionally confusing scenes from movies like Quentin Tarantino’s "Reservoir Dogs" to subjects while they were lying in a fMRI scanner. Later the participants reported whether for them each watched scene included a conflict. Furthermore they rated to which extent they felt the positive or negative elements as being dominant and, correspondingly, whether the scene was pleasant or unpleasant to watch.

This allowed researchers to pinpoint two brain areas involved in the analysis of emotional conflict: the superior temporal sulcus for the interpretation of positive situations and the inferior parietal lobule for the interpretation of negative situations. These areas were also activated when the participants felt that the movie scene represented an emotional conflict.

"The two areas seem to ‘speak’ to each other and interpret the situation in order to decide which one will be switched on and which one will be switched off, thereby determining which network will be active", said Hadas Okon-Singer, researcher at the University of Haifa. "The results suggest that these areas can influence the value, positive or negative, that will be dominant in an emotional conflict through control of other areas of the brain."

Most people’s brains manage to process such emotional conflicts properly, but some people struggle to do so. This can lead to depression, anxious rumination, and a tendency to avoid social situations. Neuroscientists Rohr and Okon-Singer therefore hope that the discovery that these two brain areas process emotionally difficult situations will now facilitate further research to examine why this mechanism does not function properly in some people: "In the end we hope our investigations enable us to develop therapeutic techniques that help people to process emotionally confusing situations more adequately."

Source via


Screen addiction is hurting kids' brains

Time to get your kid off the iPad. A new book called Glow Kids: How Screen Addiction Is Hijacking Our Kids by Dr. Nicholas Kardaras, one of the United States' top addiction experts, details how the compulsive use of technology can neurologically damage the developing brain of child—much like drug addiction can. Through extensive research, clinical trials with diagnosed screen addicts, and experience treating a variety of other types of addicts, the author explores the alarming reality of how children could be "stunting their own creative abilities" by constantly turning on and tuning in.

Even worse, according to Kardaras game developers increasingly rely on tests to measure dopamine and adrenaline levels in order to make games as addictive as possible. As a result, kids tend to become "uninterested and uninteresting", says Kardaras, only driven by the "perpetual need to be stimulated and entertained" by their digital devices. "Bored and boring, they lack a natural curiosity and a sense of wonder and imagination that non-screen kids seem to have. They don't know—or care to know—about what was happening around them in the world."

via

Our brains help us navigate by using a compressed code for what we see when we move

A new study authored by yours truly and published in the Journal of Neuroscience suggests that MSTd, a brain area dedicated to visually guided navigation, might use a highly efficient code to represent all the motions we could encounter while moving, so that we always know—with minimal effort—where we are and where we are going.

MSTd does this by learning the statistics of the motion we see when we move, and by subsequently identifying a small number of very "telling" features that together describe self-motion both accurately and efficiently.

More details can be found in this blog post. Let me know what you think!

Source

Miscellaneous

Researchers from the Johns Hopkins University have discovered the brain's "physics engine", which comes alive when people watch physical events unfold. This engine is not in the brain's vision center, but in a set of regions devoted to planning actions, suggesting the brain performs constant, real-time physics calculations so people are ready to catch, dodge, hoist or take any necessary action, on the fly. (via ScienceDaily)

French company Pixium Vision has gained the CE Mark Approval for its IRIS II retinal prosthesis, a device targeted to restore vision in people blinded by retinal disease. Analogous to a cochlear implant, the device works by translating visual input from a bio-inspired camera into small electrical pulses that are used to stimulate remaining bipolar cells in the human eye. Pixium Vision is now the third company to begin commercialization of a retinal implant-based artificial vision system, joining Second Sight and Retina Implant AG. (via MarketScope)

Dreamless sleep might store the day's sensory experiences, suggests a new mouse study from the RIKEN Brain Science Institute. Their finding suggests that it is not sleep per se that is needed for consolidation of perceptual memory, but rather the coordinated activation of a particular brain circuit. Thus, artificially stimulating the brain using magnets or electrodes could enhance memory processing in people with memory deficits due to sleep disorders. (via NeuroscienceNews)


Based on subject reports from near-death experiences, researchers from the University of Vienna have put forward the idea that the mind may function independently of its physical substrate, the brain. If the mind is just a function of the brain, it stands to reason that the worse the brain is injured, the worse the mind would function. While this is what much of current brain research is finding, a body of evidence exists suggesting otherwise: under extreme circumstances, such as close to death, the mind may function well—or even better than usual—when the brain is impaired. (via EpochTimes)

A new UC San Francisco study shows that specialized brain cells in mice "predict" the hydrating effects of drinking, deactivating long before the liquids imbibed can actually change the composition of the bloodstream. The results stand in stark contrast to current views of thirst regulation, which hold that the brain signals for drinking to stop when it detects liquid-induced changes in blood concentration or volume. (via NeuroscienceNews)

A new study from MIT revealed that the visual word form area (VWFA) in children is pre-wired to other parts of the brain in a way that makes it ideally suited to become devoted to reading—even before children know how to read. Because reading is a skill unique to humans that developed about 5,400 years ago, it is thought that evolution would not have enough time to reshape the brain accordingly. Still unknown is how and why the brain forms those connections early in life. (via NeuroscienceNews)

Researchers at Boston University and the NYU Medical Center have us once again question the well-established notion that there are two distinct visual processing streams in the brain—a "what" pathway that distinctly processes object cues, and a "where" pathway that distinctly processes spatial cues. Instead, they found that both streams encode both object and spatial information but distinctly organize memories for objects and space. Specifically, perirhinal cortex and lateral entorhinal cortex represent objects and, within the object-specific representations, the locations where they occur. Conversely, medial entorhinal cortex represents relevant locations and, within those spatial representations, the objects that occupy them. (Journal of Neuroscience)

Researchers at the University of Bristol, UK have found that acetaminophen (aka paracetamol), a commonly used pain medication, is associated with an increased risk of behavioral problems in offspring when taken during pregnancy. Prenatal maternal acetaminophen was linked to conduct problems, hyperactivity, and emotional symptoms in children. (via NeuroscienceNews)