Posts tagged psychology
Articles and news from the latest research reports.
New Study Reveals How Humans Became Right-Handed
According to a new study led by Dr Gillian Forrester of the University of Sussex, a predominance to be right-handed is not a uniquely human trait but one shared by great apes.
The study, published in the journal Behavioural Brain Research, analyzed hand actions directed towards either objects or individuals in chimpanzees, gorillas and children, and found that all three species are right-handed for actions to objects, but not for actions directed to individuals.
The results support a theory that human right-handedness is a trait developed through tool use that was inherited from an ancestor common to both humans and great apes. The findings challenge a widely held view that right-handed dominance in humans was a species-unique trait linked to the emergence of language.
“Humans have been tool users for 2.5 million years, while the current view is that language only emerged one hundred thousand years ago,” Dr Forrester said. “Our findings provide the first non-invasive results from naturalistic behavior, suggesting that language emerged as a consequence of left hemisphere brain regions that were already evolved to process regular sequences of actions. The structure found in language may have developed from pre-existing brain processes adapted from experience with tool-use.”
Let there be sight: Burst of neural activity necessary for vision
A sudden and mysterious burst of activity originating in the retina of a developing fetus spurs brain connections that are essential to development of finely-tuned sight, Yale researchers report in the journal Nature. Interference with this spontaneous wave of activity could play a role in neurodevelopmental disorders such as autism, the scientists speculate.
The study in mice is the first to demonstrate in a living animal that this wave of activity spreads throughout large regions of the brain and is crucial to wiring of the visual system. Without the wiring, infants would not be able to distinguish details in their environment.
“If you interfere with this activity, the circuits are all messed up, the wiring details are all wrong,” said Michael Crair, the William Ziegler III Professor of Neurobiology and Professor of Ophthalmology and Visual Science and senior author of the study.
For instance, this activity might allow a newborn human baby to perceive such details as the five fingers attached to her hand or her mother’s face. This wave wires up the visual system so that infants are poised to learn from their environment soon after birth.
The development of animals from a fertilized egg into trillions of intricately connected and specialized cells is the result of a precisely timed expression of genes. However, the Nature paper introduces another necessary factor — a mysterious wave of activity arising in the retina itself that propagates through several regions of the brain. Crair terms this wave an emergent property, or a trait possessed by a complex system that cannot be directly traced to its individual parts. This experiment in living, neonatal mice shows that this wave is crucial to the proper wiring not only of the visual system but other brain areas as well.
Crair said his lab plans to explore whether interruptions of this activity might play a role in neurodevelopmental disorders such as autism or schizophrenia.
(Source: news.yale.edu)
Study links eating chocolate to winning Nobels
Take this with a grain of salt, or perhaps some almonds or hazelnuts: A study ties chocolate consumption to the number of Nobel Prize winners a country has and suggests it’s a sign that the sweet treat can boost brain power.
No, this does not appear in the satirical Onion newspaper. It’s in the prestigious New England Journal of Medicine, which published it online Wednesday as a “note” rather than a rigorous, peer-reviewed study.
The author — Dr. Franz Messerli, of St. Luke’s-Roosevelt Hospital and Columbia University in New York — writes that there is evidence that flavanols in green tea, red wine and chocolate can help “in slowing down or even reversing” age-related mental decline — a contention some medical experts may dispute.
Nevertheless, he examined whether a country’s per-capita chocolate consumption was related to the number of Nobels it had won — a possible sign of a nation’s “cognitive function.” Using data from some major chocolate producers on sales in 23 countries, he found “a surprisingly powerful correlation.”
Cognitive reorganization during pregnancy and the postpartum period: An evolutionary perspective
Where the non-human animal research investigating reproduction-induced cognitive reorganization has focused on neural plasticity and adaptive advantage in response to the demands associated with pregnancy and parenting, human studies have primarily concentrated on pregnancy-induced memory decline. The current review updates Henry and Rendell’s 2007 meta-analysis, and examines cognitive reorganization as the result of reproductive experience from an adaptationist perspective. Investigations of pregnancy-induced cognitive change in human females may benefit by focusing on areas, such as social cognition, where a cognitive advantage would serve a protective function, and by extending the study duration beyond pregnancy into the postpartum period.
(Source: epjournal.net)
A wireless low-power, high-quality EEG headset
Imec, Holst Centre and Panasonic have developed a new prototype of a wireless EEG (electroencephalogram, or brain waves) headset designed to be a reliable, high-quality and wearable EEG monitoring system.
The system combines ease-of-use with ultra-low power electronics. Continuous impedance monitoring and the use of active electrodes increases the quality of EEG signal recording compared to former versions of the system.
The EEG data is transmitted to a receiver located up to 10 meters away. The headset integrates active electrodes (reduce the susceptibility of the system to power-line interference and cable motion artifacts to improve signal quality), EEG amplifier, microcontroller, and low-power wireless transmitter.
The receiver can continuously record 8-channel EEG signals while concurrently recording electrode-tissue contact impedance (ETI), a measure of contact quality.
The system has a high (>92 dB) common-mode rejection ratio (to reduce interference from power lines and other sources) and low noise (<6 µVpp, 0.5-100Hz), with configurable cut-off frequency (to filter out high or low frequencies).
The heart of the system is the low-power (750µW) 8-channel EEG monitoring chipset. Each EEG channel consists of two active electrodes and a low-power analog signal processor. The EEG channels are designed to extract high-quality EEG signals under a large amount of common-mode interference. The active electrode chips have buffer functionality with high input impedance (1.4GΩ at 10Hz), enabling recordings from dry electrodes, and low output impedance reducing the power-line interference without using shielded wires
The system is integrated into imec’s EEG headset with dry electrodes, which enables EEG recordings with minimal set-up time. The small size of the electronics system, measuring only 35mm x 30mm x 5mm (excluding battery), allows easy integration in any other product.
![Singing Mice Show Signs of Learning
Guys who imitate Luciano Pavarotti or Justin Bieber to get the girls aren’t alone. Male mice may do a similar trick, matching the pitch of other males’ ultrasonic serenades. The mice also have certain brain features, somewhat similar to humans and song-learning birds, which they may use to change their sounds, according to a new study.
"We are claiming that mice have limited versions of the brain and behavior traits for vocal learning that are found in humans for learning speech and in birds for learning song," said Duke neurobiologist Erich Jarvis, who oversaw the study. The results appear Oct. 10 in PLOS ONE and are further described in a review article in Brain and Language.[Arriaga, G. et. al. (2012) “Mouse vocal communication system: are ultrasounds learned or innate?” Brain and Language]
The discovery contradicts scientists’ 60-year-old assumption that mice do not have vocal learning traits at all. “If we’re not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders,” said Jarvis, who is a Howard Hughes Medical Institute investigator. “The researchers who use mouse models of the vocal communication effects of these diseases will finally know the brain system that controls the mice’s vocalizations.”](http://41.media.tumblr.com/tumblr_mbq8pdtDce1rog5d1o1_400.jpg)
Singing Mice Show Signs of Learning
Guys who imitate Luciano Pavarotti or Justin Bieber to get the girls aren’t alone. Male mice may do a similar trick, matching the pitch of other males’ ultrasonic serenades. The mice also have certain brain features, somewhat similar to humans and song-learning birds, which they may use to change their sounds, according to a new study.
"We are claiming that mice have limited versions of the brain and behavior traits for vocal learning that are found in humans for learning speech and in birds for learning song," said Duke neurobiologist Erich Jarvis, who oversaw the study. The results appear Oct. 10 in PLOS ONE and are further described in a review article in Brain and Language.
[Arriaga, G. et. al. (2012) “Mouse vocal communication system: are ultrasounds learned or innate?” Brain and Language]The discovery contradicts scientists’ 60-year-old assumption that mice do not have vocal learning traits at all. “If we’re not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders,” said Jarvis, who is a Howard Hughes Medical Institute investigator. “The researchers who use mouse models of the vocal communication effects of these diseases will finally know the brain system that controls the mice’s vocalizations.”
What Drives Your Daily Biological Clock?
Researchers working with fruit flies say they have discovered one way that the body’s biological clock controls brain-cell activity that influences daily rhythms.
They believe their findings might improve understanding about sleep-wake cycles and lead to new treatments for sleep disorders and jet lag.
"The findings answer a significant question: how biological clocks drive the activity of clock neurons, which, in turn, regulate behavioral rhythms," study senior author Justin Blau, associate professor in New York University’s department of biology, said in a university news release.
Previous research with fruit flies’ “clock genes” led to the discovery of similar genes in humans, according to the news release.
It was known that biological clocks control neuronal activity, but it wasn’t known how information from biological clocks drives rhythms in the electrical activity of pacemaker neurons that control daily rhythms.
The NYU team looked at pacemaker neurons in the central brain of fruit flies that set the timing of the daily transitions between sleep and wake. They isolated these neurons and identified sets of genes with different levels of activity at dawn and dusk.
Follow-up experiments found that the activity of a gene called Ir was much higher at dusk than at dawn and that it was more active in the pacemaker neurons than in the rest of the brain. The researchers also found that increasing or decreasing levels of Ir affected behavioral rhythms and changed the timing and strength of variations in the core clock.
"We were looking for an output of the biological clock that would link the core clock to neuronal activity," Blau said. "Ir seems to do this, but it also, remarkably, feeds back to regulate the core clock itself. Feedback loops seem to be deeply engrained into the biological clock and presumably help these clocks work so well."
The study was published in the October issue of the Journal of Biological Rhythms. Researchers have noted that results from animal studies do not necessarily translate to humans.
Memory: Do animals ever forget?
From pigeons that can recognise faces to a chimp that stores rocks to throw at visitors, all animals have memories. But how similar are they to ours?
(Image: Matt Jacob/Tendance Floue)
EVERY morning, you take a walk in the park, bringing some bread to feed the pigeons. As the days wear on, you begin to see the birds as individuals; you even start to name them. But what do the pigeons remember of you? Do they think kindly of you as they drop off to sleep at night, or is your face a blank, indistinguishable from the others strolling through the park?
These questions may seem whimsical, but knowing what other creatures recall is crucial if we are to understand their inner lives. It turns out that the range of mnemonic feats in the wild is nearly as varied as life itself.
If you take memory to mean any ability to store and respond to past events, even the simplest organisms meet the grade. Blobs of slime mould, for instance, which can slowly crawl across a surface, seem to note the timing of changes to their climate, slowing their movement in anticipation of an expected dry spell - even when it never actually arrives.
With the emergence of the first neurons about half a billion years ago, memories became more intricate as information could be stored in the patterns of electrical connections within the nervous system. This type of learning may have been behind the Cambrian explosion - the sudden appearance and rapid evolution of more complex species about 530 million years ago - because it enabled animals to exploit new niches, say Eva Jablonka at Tel Aviv University and Simona Ginsburg at the Open University of Israel.
Over the following few hundred million years, increasingly advanced skills could emerge with different forces driving the evolution of each creature’s mind. The result is a surprising range of mnemonic feats throughout the animal kingdom. Migratory cardinal fish, for instance, can remember where they laid their eggs during the breeding season and, after over-wintering in deep water, return to within half a metre of the same spot. Animals as diverse as lizards, bees and octopuses can learn the way out of a maze, and pigeons have an excellent visual recognition, learning to recognise more than a thousand different images. They can even recognise individual humans and aren’t fooled by a change of clothes.
Such skills, although impressive, don’t match our experiences of episodic memory, in which we immerse ourselves in specific events. A pigeon might learn to associate your face with food, but it probably can’t remember your last meeting in the way you might be able to recall details of your last trip to the park.
Angry? Sad? Ashamed? Depressed people can’t tell difference
Clinically depressed people have a hard time telling the difference between negative emotions such as anger and guilt, a new University of Michigan study found.
The ability to distinguish between various emotional experiences affects how individuals deal with life stressors, said Emre Demiralp, a researcher in the U-M Department of Psychology and the lead author of the study recently published in Psychological Science.
Being unable to differentiate certain emotions from each other might lead to a person choosing an action that is not appropriate, thus exacerbating the problem, she said.
"It is difficult to improve your life without knowing whether you are sad or angry about some aspect of it," Demiralp said. "For example, imagine not having a gauge independently indicating the gasoline level of your car. It would be challenging to know when to stop for gas.
"We wanted to investigate whether people with clinical depression had emotional gauges that were informative and whether they experienced emotions with the same level of specificity and differentiation as healthy people."
Caffeine may block inflammation linked to mild cognitive impairment
(Image credit: chichacha)
Recent studies have linked caffeine consumption to a reduced risk of Alzheimer’s disease, and a new University of Illinois study may be able to explain how this happens.
“We have discovered a novel signal that activates the brain-based inflammation associated with neurodegenerative diseases, and caffeine appears to block its activity. This discovery may eventually lead to drugs that could reverse or inhibit mild cognitive impairment,” said Gregory Freund, a professor in the U of I’s College of Medicine and a member of the U of I’s Division of Nutritional Sciences.
Freund’s team examined the effects of caffeine on memory formation in two groups of mice—one group given caffeine, the other receiving none. The two groups were then exposed to hypoxia, simulating what happens in the brain during an interruption of breathing or blood flow, and then allowed to recover.
The caffeine-treated mice recovered their ability to form a new memory 33 percent faster than the non-caffeine-treated mice. In fact, caffeine had the same anti-inflammatory effect as blocking IL-1 signaling. IL-1 is a critical player in the inflammation associated with many neurodegenerative diseases, he said.
“It’s not surprising that the insult to the brain that the mice experienced would cause learning memory to be impaired. But how does that occur?” he wondered.
The scientists noted that the hypoxic episode triggered the release of adenosine by brain cells.
“Your cells are little powerhouses, and they run on a fuel called ATP that’s made up of molecules of adenosine. When there’s damage to a cell, adenosine is released,” he said.
Just as gasoline leaking out of a tank poses a danger to everything around it, adenosine leaking out of a cell poses a danger to its environment, he noted.
The extracellular adenosine activates the enzyme caspase-1, which triggers production of the cytokine IL-1β, a critical player in inflammation, he said.
“But caffeine blocks all the activity of adenosine and inhibits caspase-1 and the inflammation that comes with it, limiting damage to the brain and protecting it from further injury,” he added.
Caffeine’s ability to block adenosine receptors has been linked to cognitive improvement in certain neurodegenerative diseases and as a protectant against Alzheimer’s disease, he said.
“We feel that our foot is in the door now, and this research may lead to a way to reverse early cognitive impairment in the brain. We already have drugs that target certain adenosine receptors. Our work now is to determine which receptor is the most important and use a specific antagonist to that receptor,” he said.
The study appears in the Journal of Neuroscience and can be viewed online at http://www.jneurosci.org/content/32/40/13945.full
(Source: news.aces.illinois.edu)