By exploring parts of the brain that trigger during periods of daydreaming and mind-wandering, neuroscientists from Western University have made a significant breakthrough in understanding what physically happens in the brain to cause vegetative state and other so-called “disorders of consciousness.”
Vegetative state and related disorders such as the minimally conscious state are amongst the least understood conditions in modern medicine because there is no particular type of brain damage that is known to cause them. This lack of knowledge leads to an alarmingly high level of misdiagnosis.
In support of the study titled, “A role for the default mode network in the bases of disorders of consciousness,” Davinia Fernandez-Espejo, a post doctoral fellow at Western’s Brain and Mind Institute, utilized a technique called diffusion tensor imaging tractography to investigate more than 50 patients suffering from varying degrees of brain injury.
This state-of-the-art magnetic resonance imaging (MRI) technique allows researchers to virtually reconstruct the pathways that connect different parts of the brain in the patients while detecting subtle differences in their brain damage.
Specifically, Fernandez-Espejo was able to show that in vegetative state patients, a group of brain regions known as the default mode network that are known to activate during periods of daydreaming and mind-wandering were significantly disconnected, relative to healthy individuals.
"These findings are a first step towards identifying biomarkers that will help us to improve diagnosis and to find possible therapies for these patients" says Fernandez-Espejo. "But they also give us new information about how the healthy brain generates consciousness."
(Source: communications.uwo.ca)
Filed under brain diffusion tensor imaging vegetative state brain injury consciousness neuroscience psychology science
Compassion meditation may boost neural basis of empathy
A compassion-based meditation program can significantly improve a person’s ability to read the facial expressions of others, finds a study published by Social Cognitive and Affective Neuroscience. This boost in empathic accuracy was detected through both behavioral testing of the study participants and through functional magnetic resonance imaging (fMRI) scans of their brain activity.
“It’s an intriguing result, suggesting that a behavioral intervention could enhance a key aspect of empathy,” says lead author Jennifer Mascaro, a post-doctoral fellow in anthropology at Emory University. “Previous research has shown that both children and adults who are better at reading the emotional expressions of others have better relationships.”
The meditation protocol, known as Cognitively-Based Compassion Training, or CBCT, was developed at Emory by study co-author Lobsang Tenzin Negi, director of the Emory-Tibet Partnership. Although derived from ancient Tibetan Buddhist practices, the CBCT program is secular in content and presentation.
Filed under brain meditation empathy cognition CBCT compassion neuroscience psychology science
Is attenuated psychosis syndrome likely to appear in the DSM-5? Members of the DSM-5 Psychotic Disorder Work Group have been debating the issue for some time. Here, Dr. William Carpenter, head of the work group, explains why attenuated psychosis syndrome will probably end up in section III of the manual, which means more research is needed.
Filed under brain mental illness DSM-5 APS psychosis neuroscience psychology science
Strokes often cause loss or impairment of vital brain functions – such as speech, movement, vision or attention. Restoration of these functions is often possible, but difficult. One of the factors impeding brain plasticity is inflammation. A study on rats, carried out at the Nencki Institute in Warsaw, suggests that effectiveness of neurorehabilitation after a stroke can be improved by anti-inflammatory drugs.
Post-stroke inflammation slows down recovery and impairs brain plasticity, reveal the results from the lab of Professor Małgorzata Kossut at the Nencki Institute in Warsaw. The popular anti-inflammatory drug ibuprofen restores the ability of brain cortex to reorganize – a process necessary for recovery of stroke-damaged functions. “Our research was conducted on rats, but we have good reasons to suppose that in future our results will help improve effectiveness of rehabilitation of stroke patients”, says Prof. Kossut.
The Nencki Institute team stresses that so far there are no proofs that the treatment will be effective in humans and that they did not investigate if the ibuprofen therapy prevents strokes, but concentrated on post-stroke recovery.
The most frequent cause of stroke is blocking of brain arteries. Without supply of oxygen, neurons die quckly. In the region of stroke-induced damage pathological changes cause decrease of brain tissue metabolism, impairment of neurotransmission and edema.
Brain control over physiological and voluntary functions may be lost, depending on the localization of the infarct. Impairments of movement, vision, speech and attention are frequent. In most cases these functions return either partially or completely. Sometimes they return spontaneously, more often after neurorehabilitation.
“In both instances recovery is based on neuroplasticity, the ability of the brain to reorganize, that is to change the properties of neurons and to alter the connections between them”, says Dr. Monika Liguz-Lęcznar (Nencki Institute).
After a stroke, neuroplasticity is impaired. Scientists from the Nencki Institute suppose that this may be due to inflammation developing at the site of the stroke. The proof that decreasing inflammation helps neurorehabilitation came from experiments done on rats with experimentally induced stroke. The stroke was localized in a special region of the brain cortex, receiving information from whiskers.
The whiskers are important sensory organs of rodents, allowing the animals to orient themselves in their environment in darkness. Every whisker activates a small, precisely delineated chunk of brain cortex.
In healthy rats neuroplastic changes can be induced by cutting off some of the whiskers, that is by eliminating part of the sensory input to the brain. The brain reacts to that by letting the remaining whiskers take over more cortical space, expand their cortical representation, at the expense of the cut off ones.
“This plastic change does not occur when the site of stroke-induced damage is near the region of cortex ‘belonging’ to the whiskers. We showed that application of ibuprofen decreases inflammation and restores neuroplasticity – the brain cortex reorganizes like in healthy animals”, says Prof. Kossut.
(Source: press.nencki.gov.pl)
Filed under brain stroke plasticity anti-inflammatory drugs neuroscience psychology science
When Less Is More: Evolutionary Origins of the Affect Heuristic
The human mind is built for approximations. When considering the value of a large aggregate of different items, for example, we typically do not summate the many individual values. Instead, we appear to form an immediate impression of the likeability of the option based on the average quality of the full collection, which is easier to evaluate and remember. While useful in many situations, this affect heuristic can lead to apparently irrational decision-making. For example, studies have shown that people are willing to pay more for a small set of high-quality goods than for the same set of high-quality goods with lower-quality items added [e.g. 1]. We explored whether this kind of choice behavior could be seen in other primates. In two experiments, one in the laboratory and one in the field, using two different sets of food items, we found that rhesus monkeys preferred a highly-valued food item alone to the identical item paired with a food of positive but lower value. This finding provides experimental evidence that, under certain conditions, macaque monkeys follow an affect heuristic that can cause them to prefer less food. Conservation of this affect heuristic could account for similar ‘irrational’ biases in humans, and may reflect a more general complexity reduction strategy in which averages, prototypes, or stereotypes represent a set or group.
Filed under brain primates decision-making irrational decisions neuroscience psychology science
Philosophy will be the key that unlocks artificial intelligence
To state that the human brain has capabilities that are, in some respects, far superior to those of all other known objects in the cosmos would be uncontroversial. The brain is the only kind of object capable of understanding that the cosmos is even there, or why there are infinitely many prime numbers, or that apples fall because of the curvature of space-time, or that obeying its own inborn instincts can be morally wrong, or that it itself exists. Nor are its unique abilities confined to such cerebral matters. The cold, physical fact is that it is the only kind of object that can propel itself into space and back without harm, or predict and prevent a meteor strike on itself, or cool objects to a billionth of a degree above absolute zero, or detect others of its kind across galactic distances.
But no brain on Earth is yet close to knowing what brains do in order to achieve any of that functionality. The enterprise of achieving it artificially – the field of “artificial general intelligence” or AGI – has made no progress whatever during the entire six decades of its existence.
Despite this long record of failure, AGI must be possible. That is because of a deep property of the laws of physics, namely the universality of computation. It entails that everything that the laws of physics require physical objects to do can, in principle, be emulated in arbitrarily fine detail by some program on a general-purpose computer, provided it is given enough time and memory.
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Filed under brain AI artificial general intelligence self-awareness neuroscience technology science
Drug Reverses Abnormal Brain Function in Rett Syndrome Mice
A promising study out today in the prestigious Journal of Neuroscience showed that in a mouse model of Rett syndrome, researchers were able to reverse abnormalities in brain activity and improve neurological function by treating the animals with an FDA-approved anesthesia drug, ketamine. Rett syndrome is among the most severe autism-related disorders, affecting about one in 10,000 female births per year, with no effective treatments available.
“These studies provide new evidence that drug treatment can reverse abnormalities in brain function in Rett syndrome mice,” says David Katz, PhD, professor of neurosciences, Case Western Reserve University School of Medicine and senior author of the study. “They also provide new leads as to what kinds of drugs might be effective in individuals with Rett syndrome.”
Neuroscientists at Case Western Reserve University School of Medicine were able to successfully map differences in the brain activity of normal mice and those with a genetic mutation that mirrors the cause of Rett syndrome in humans. They found that – compared to normal mice – Rett syndrome mice showed regions of abnormally low activity in the front of the brain (forebrain) and regions of abnormally high activity in the back of the brain (brainstem). Importantly, they found that the regions of low activity overlap with regions of the brain that are also under-active in humans with classic autism. This indicates there may be common mechanisms underlying abnormal behaviors in the two diseases.
The identification of these brain regions provided clues into specific areas to target for treatment. Based on previously published findings that ketamine activated neurons in the forebrain, the researchers gave the drug to the Rett syndrome mice and found it increased levels of brain activity in those regions and improved neurological function. Importantly, the drug was effective at a low dose that did not produce anesthesia.
Filed under brain rett syndrome ketamine autism neuroscience psychology science
![When Less Is More: Evolutionary Origins of the Affect Heuristic
The human mind is built for approximations. When considering the value of a large aggregate of different items, for example, we typically do not summate the many individual values. Instead, we appear to form an immediate impression of the likeability of the option based on the average quality of the full collection, which is easier to evaluate and remember. While useful in many situations, this affect heuristic can lead to apparently irrational decision-making. For example, studies have shown that people are willing to pay more for a small set of high-quality goods than for the same set of high-quality goods with lower-quality items added [e.g. 1]. We explored whether this kind of choice behavior could be seen in other primates. In two experiments, one in the laboratory and one in the field, using two different sets of food items, we found that rhesus monkeys preferred a highly-valued food item alone to the identical item paired with a food of positive but lower value. This finding provides experimental evidence that, under certain conditions, macaque monkeys follow an affect heuristic that can cause them to prefer less food. Conservation of this affect heuristic could account for similar ‘irrational’ biases in humans, and may reflect a more general complexity reduction strategy in which averages, prototypes, or stereotypes represent a set or group.](http://40.media.tumblr.com/tumblr_mbd700dE171rog5d1o1_500.png)
