Posts tagged neuroscience
Articles and news from the latest research reports.
Zooming in on the human brain
A visually compelling tour of the human brain, from anatomy to cells to genes and back.
Could neuroscientists be the next great architects?
Socrates Method Of Memory Works Just As Well Using Virtual Reality
In the episode of NOVA that aired October 24 of this year, host David Pogue posed the question, “How Smart Can We Get?” At one point in the episode, he met with Chester Santos, who was the 2008 US Memory Champion, to pick his brain on how he manages to learn long strings of numbers and words. Santos taught him a technique that involved visualization of objects that were in Pogue’s own house and associating them with the string of non-related words. It turns out this technique is nothing new. Its roots stem all the way back to the time of Socrates, in fact.
A new research study conducted by a team from the University of Alberta has revisited this age old technique giving it a modern-day twist.
The memory technique, called loci, or location, by the ancient Greeks, was used by Socrates, according to classic scholars, to memorize his oratories. To do this, Socrates would wander around his home and assign a word or fact that he needed to memorize some familiar object or structure in his home.
At the time that Socrates needed to recall this information in front of an audience, he would simply conjure up his home and, in his mind, the words that he had linked to things like his window or table would instantly be recalled.
“Nowadays many contestants in memory competitions use this same technique,” said lead researcher Eric Legge. “They use the location method to instantly recall everything from words to a long list of random numbers.”
Legge, along with his U of A research colleague Christopher Madan, developed a virtual living-space environment. This virtual living room would allow their test subjects to use the ancient Greek technique to increase their memory ability.
In everyday life we rarely consciously try to lip-read. However, in a noisy environment it is often very helpful to be able to see the mouth of the person you are speaking to. Researcher Helen Blank at the MPI in Leipzig explains why this is so: “When our brain is able to combine information from different sensory sources, for example during lip-reading, speech comprehension is improved.” In a recent study, the researchers of the Max Planck Research Group “Neural Mechanisms of Human Communication” investigated this phenomenon in more detail to uncover how visual and auditory brain areas work together during lip-reading.
In the experiment, brain activity was measured using functional magnetic resonance imaging (fMRI) while participants heard short sentences. The participants then watched a short silent video of a person speaking. Using a button press, participants indicated whether the sentence they had heard matched the mouth movements in the video. If the sentence did not match the video, a part of the brain network that combines visual and auditory information showed greater activity and there were increased connections between the auditory speech region and the STS.
“It is possible that advanced auditory information generates an expectation about the lip movements that will be seen”, says Blank. “Any contradiction between the prediction of what will be seen and what is actually observed generates an error signal in the STS.”
How strong the activation is depends on the lip-reading skill of participants: The strong-er the activation, the more correct responses were. “People that were the best lip-readers showed an especially strong error signal in the STS”, Blank explains. This effect seems to be specific to the content of speech - it did not occur when the subjects had to decide if the identity of the voice and face matched.
The results of this study are very important to basic research in this area. A better understanding of how the brain combines auditory and visual information during speech processing could also be applied in clinical settings. “People with hearing impairment are often strongly dependent on lip-reading”, says Blank. The researchers suggest that further studies could examine what happens in the brain after lip-reading training or during a combined use of sign language and lip-reading.
Foetus suffers when mother lacks vitamin C
Maternal vitamin C deficiency during pregnancy can have serious consequences for the foetal brain. And once brain damage has occurred, it cannot be reversed by vitamin C supplements after birth. This is shown through new research at the University of Copenhagen just published in the scientific journal PLOS ONE.
Neuroscientists develop word concept mind-reading tool
A team of cognitive neuroscientists has identified the areas of the brain responsible for processing specific words meanings, bringing us one step closer to developing multilingual mind reading machines.
Presenting the findings at the Society for the Neurobiology of Language Conference in San Sebastián, Spain, Joao Correia of Maastricht University explained that his team decided to answer one central question: “how do we represent the meaning of words independent of the language we are listening to?”
Past studies have focused on identifying areas of the brain that generate and hear general terms or feelings. However, if we can locate where the actual concept of a word — which transcends language — is processed, we would be able to read the mind of any individual. The recent case of 39-year-old Scott Routley letting doctors know he is not in pain, just by thinking, is a prime example of where this could be extremely effective in the future. After not responding to any stimulation for more than a decade, Routley was thought to be in a persistent vegetative state. However, by studying fMRI scans in real time neurologists could identify that Routley was in fact responding to their questions — they asked him to think about playing tennis or walking around at home to indicate yes or no. These two actions are processed in different areas of the brain, so answers could be extracted by reading scans. With Correia’s approach, we would need no signifier for yes or no — we could go straight to the source where the processing of the meaning of positive and negative takes place; the “hub”, as he puts it.
"This fMRI study investigates the neural network of speech processing responsible for transforming sound to meaning, by exploring the semantic similarities between bilingual wordpairs," explains an abstract of the study. To achieve this, they needed bilingual volunteers, so worked with eight Dutch candidates all fluent in English. First off, the team monitored the volunteers’ neural activity while saying the words "bull", "horse", "shark" and "duck" in English. All the words chosen had one syllable, were from a similar group and were probably learnt round the same period — this ensured that any differences would specifically relate to meaning. Different brain activity patterns appeared in the left anterior temporal cortex, and each of these were then fed into an algorithm so it would be able to flag up when one of the words was uttered again.
The hypothesis was, if the algorithm could still correctly identify the words when they were spoken in Dutch, these patterns would hold the key to where the word concepts are derived. The algorithm did exactly that. It demonstrates that words are encoded in the same way in the brain, regardless of language.
There is one pretty major drawback to the process, which quashes any visions of a full-on real-time mind translation machine hitting stores anytime soon — the neural activity patterns differed slightly from person to person. Our neurons learn and identify in unique ways, and understanding these pathway patterns through machine learning would be a long process. “You would have to scan a person as they thought their way through a dictionary,” said Matt Davis of the MRC Cognition and Brain Sciences Unit in Cambridge. It would be difficult to translate a mind now without this concept map. However, we are only at the beginning of this line of study, and an algorithm could potentially be devised to aggregate hundreds of neural activity patterns to help indicate what the brain activity of an individual unable to communicate represents.
Brazilian Mediums Shed Light on Brain Activity During a Trance State
Researchers at Thomas Jefferson University and the University of Sao Paulo in Brazil analyzed the cerebral blood flow (CBF) of Brazilian mediums during the practice of psychography, described as a form of writing whereby a deceased person or spirit is believed to write through the medium’s hand. The new research revealed intriguing findings of decreased brain activity during the mediums’ dissociative state which generated complex written content. Their findings appear in the November 16th edition of the online journal PLOS ONE.
The 10 mediums—five less expert and five experienced—were injected with a radioactive tracer to capture their brain activity during normal writing and during the practice of psychography which involves the subject entering a trance-like state. The subjects were scanned using SPECT (single photon emission computed tomography) to highlight the areas of the brain that are active and inactive during the practice.
The researchers found that the experienced psychographers showed lower levels of activity in the left hippocampus (limbic system), right superior temporal gyrus, and the frontal lobe regions of the left anterior cingulate and right precentral gyrus during psychography compared to their normal (non-trance) writing. The frontal lobe areas are associated with reasoning, planning, generating language, movement, and problem solving, perhaps reflecting an absence of focus, self-awareness and consciousness during psychography, the researchers hypothesize.
Less expert psychographers showed just the opposite—increased levels of CBF in the same frontal areas during psychography compared to normal writing. The difference was significant compared to the experienced mediums. This finding may be related to their more purposeful attempt at performing the psychography. The absence of current mental disorders in the groups is in line with current evidence that dissociative experiences are common in the general population and not necessarily related to mental disorders, especially in religious/spiritual groups. Further research should address criteria for distinguishing between healthy and pathological dissociative expressions in the scope of mediumship.
Functional Connectivity and Tuning Curves in Populations of Simultaneously Recorded Neurons
How interactions between neurons relate to tuned neural responses is a longstanding question in systems neuroscience. Here we use statistical modeling and simultaneous multi-electrode recordings to explore the relationship between these interactions and tuning curves in six different brain areas. We find that, in most cases, functional interactions between neurons provide an explanation of spiking that complements and, in some cases, surpasses the influence of canonical tuning curves. Modeling functional interactions improves both encoding and decoding accuracy by accounting for noise correlations and features of the external world that tuning curves fail to capture. In cortex, modeling coupling alone allows spikes to be predicted more accurately than tuning curve models based on external variables. These results suggest that statistical models of functional interactions between even relatively small numbers of neurons may provide a useful framework for examining neural coding.
Wandering Minds Associated With Aging Cells
Scientific studies have suggested that a wandering mind indicates unhappiness, whereas a mind that is present in the moment indicates well-being. Now a preliminary UCSF study suggests a possible link between mind wandering and aging, by looking at a biological measure of longevity.
In the study, telomere length, an emerging biomarker for cellular and general bodily aging, was assessed in association with the tendency to be present in the moment versus the tendency to mind wander, in research on 239 healthy, midlife women ranging in age from 50 to 65 years.
Being present in the moment was defined as an inclination to be focused on current tasks, while mind wandering was defined as the inclination to have thoughts about things other than the present or being elsewhere.
According to the findings, published online on Nov. 15 in the new Association for Psychological Science journal Clinical Psychological Science, those who reported more mind wandering had shorter telomeres, while those who reported more presence in the moment, or having a greater focus and engagement with their current activities, had longer telomeres, even after adjusting for current stress.
Neuroscience gets behind the mask of Greek theatre
Over 2000 years may have elapsed since masked Greek tragedies had their heyday on stage in Athens, but some of the most modern neuroscience may be able to give classicists a better understanding of how the ancients watched and thought about those plays that today exist only on paper.