Neuroscience

Articles and news from the latest research reports.

Posts tagged neuroscience

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Yale scientists explain how ketamine vanquishes depression within hours
Many chronically depressed and treatment-resistant patients experience immediate relief from symptoms after taking small amounts of the drug ketamine. For a decade, scientists have been trying to explain the observation first made at Yale University.
Today, current evidence suggests that the pediatric anesthetic helps regenerate synaptic connections between brain cells damaged by stress and depression, according to a review of scientific research written by Yale School of Medicine researchers and published in the Oct. 5 issue of the journal Science.
Ketamine works on an entirely different type of neurotransmitter system than current antidepressants, which can take months to improve symptoms of depression and do not work at all for one out of every three patients.  Understanding how ketamine works in the brain could lead to the development of an entirely new class of antidepressants, offering relief for tens of millions of people suffering from chronic depression.
“The rapid therapeutic response of ketamine in treatment-resistant patients is the biggest breakthrough in depression research in a half century,” said Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and Professor of Neurobiology.

Yale scientists explain how ketamine vanquishes depression within hours

Many chronically depressed and treatment-resistant patients experience immediate relief from symptoms after taking small amounts of the drug ketamine. For a decade, scientists have been trying to explain the observation first made at Yale University.

Today, current evidence suggests that the pediatric anesthetic helps regenerate synaptic connections between brain cells damaged by stress and depression, according to a review of scientific research written by Yale School of Medicine researchers and published in the Oct. 5 issue of the journal Science.

Ketamine works on an entirely different type of neurotransmitter system than current antidepressants, which can take months to improve symptoms of depression and do not work at all for one out of every three patients.  Understanding how ketamine works in the brain could lead to the development of an entirely new class of antidepressants, offering relief for tens of millions of people suffering from chronic depression.

“The rapid therapeutic response of ketamine in treatment-resistant patients is the biggest breakthrough in depression research in a half century,” said Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and Professor of Neurobiology.

Filed under brain depression ketamine antidepressants neuroscience psychology science

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Nearly 100 years after a British neurologist first mapped the blind spots caused by missile wounds to the brains of soldiers, Perelman School of Medicine researchers at the University of Pennsylvania have perfected his map using modern-day technology. Their results create a map of vision in the brain based upon an individual’s brain structure, even for people who cannot see. Their result can, among other things, guide efforts to restore vision using a neural prosthesis that stimulates the surface of the brain. The study appears in the latest issue of Current Biology, a Cell Press journal.

Nearly 100 years after a British neurologist first mapped the blind spots caused by missile wounds to the brains of soldiers, Perelman School of Medicine researchers at the University of Pennsylvania have perfected his map using modern-day technology. Their results create a map of vision in the brain based upon an individual’s brain structure, even for people who cannot see. Their result can, among other things, guide efforts to restore vision using a neural prosthesis that stimulates the surface of the brain. The study appears in the latest issue of Current Biology, a Cell Press journal.

Filed under brain fMRI vision brain anatomy neuroscience psychology science

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Finches flirt unwisely if they can only use their left eyes
A patch over a male Gouldian finch’s right eye works like beer goggles, though the bird doesn’t need booze to flirt unwisely. If limited to using his left eye when checking out possible mates, he risks making really stupid choices.
Gouldian finches have caps of black, red or yellow feathers on their heads. In nature, the birds prefer to mate with partners with the same cap color. Yet black-headed males rendered temporarily left-eyed by a tiny removable eye patch flirted as readily with red-heads as with black-heads, says cognitive ecologist Jennifer Templeton of Knox College in Galesburg, Ill. That’s not smart because daughters typically fail to survive when Gouldian finches mate outside their cap color.
Also the male himself “becomes less attractive,” Templeton says. When the bird’s right eye was covered, he sang, bowed and posed less during his attempts at courtship. Some left-eyed males didn’t manage to make up their minds at all, but “just hopped around randomly,” Templeton says.

[Full article] In the eye of the beholder: visual mate choice lateralization in a polymorphic songbird
Finches flirt unwisely if they can only use their left eyes

A patch over a male Gouldian finch’s right eye works like beer goggles, though the bird doesn’t need booze to flirt unwisely. If limited to using his left eye when checking out possible mates, he risks making really stupid choices.

Gouldian finches have caps of black, red or yellow feathers on their heads. In nature, the birds prefer to mate with partners with the same cap color. Yet black-headed males rendered temporarily left-eyed by a tiny removable eye patch flirted as readily with red-heads as with black-heads, says cognitive ecologist Jennifer Templeton of Knox College in Galesburg, Ill. That’s not smart because daughters typically fail to survive when Gouldian finches mate outside their cap color.

Also the male himself “becomes less attractive,” Templeton says. When the bird’s right eye was covered, he sang, bowed and posed less during his attempts at courtship. Some left-eyed males didn’t manage to make up their minds at all, but “just hopped around randomly,” Templeton says.

[Full article] In the eye of the beholder: visual mate choice lateralization in a polymorphic songbird

Filed under birds brain mating visual lateralization neuroscience psychology science

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Western neuroscientists breakthrough on physical cause of vegetative state

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

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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.

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

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A popular medicine helps repair brain after a stroke – for now, in rats

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

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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.

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

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