Despite all that contemporary medicine knows about psychology, neurology and human behavior, it has yet to devise anything that works better than Alcoholics Anonymous to help drunks stay sober.
What makes the first impression last?
March 25, 2010 By Leave a Comment
London, Mar 25 (ANI): Scientists at Cedars-Sinai Medical Center and the California Institute of Technology have found how the memory of a first impression lasts in the brain.
They have suggested that when memory-related neurons in the brain fire in sync with certain brain waves, the resulting image recognition and memories are stronger than if this synchronization does not occur.
Synchronization is influenced by “theta waves,” which are associated with relaxation, daydreaming and drowsiness, but also with learning and memory formation.
While it has long been understood that a relaxed mind is one that is ready to receive new information, the study pinpoints a mechanism by which this state of mind allows neurons to work together to improve memory retention.
Further exploration of these events could have implications for developing new therapies to treat learning disabilities and some types of dementia, according to the authors.
“Theta oscillations are known to be involved in memory formation, and previous studies have identified correlations between memory strength and the activity of certain neurons, but the relationships between these events have not been understood. Our research shows that when memory-related neurons are well coordinated to theta waves during the learning process, memories are stronger,” said Dr. Adam N. Mamelak.
“We have yet to discover all factors that influence theta oscillations and the coordination of spike timing, but this study establishes a direct relationship between events at the circuit level of the brain – individual neuron spike timing relative to the local brain wave environment – and their effects on human behavior,” said Dr. Ueli Rutishauser.
He said that the study also found that while the predictability of memory strength was determined by spike timing relative to theta oscillations, it was not influenced by other related factors, such as the neuron-firing rate or the amplitude of the theta oscillations.
This study was conducted with eight volunteers who suffer from epilepsy and were undergoing intracranial EEGs.
The authors note that steps were taken to ensure that the patients” underlying medical condition did not affect the outcome of the study.
The study has been published in the journal Nature. (ANI)
Neanderthals may have acted in much the same way as early modern humans
April 7, 2009 By Leave a Comment
Washington, April 7 (ANI): A new study has suggested that Neanderthals may have acted in much the same way as early modern humans, and were much savvier than previously thought.
According to a report in the Scientific American, to compare the behavior of Neanderthals and early moderns, paleoanthropologist Bruce Hardy of Kenyon College studied artifacts from a site in southwestern Germany called Hohle Fels.
The site contains several levels of archaeological remains.
One of these levels dates to between 36,000 and 40,000 years ago and contains tools manufactured in the Mousterian cultural tradition associated with Neanderthals.
Another comprises items that are 33,000 to 36,000 years old and are made in the Aurignacian style associated with early modern humans.
What makes Hohle Fels ideal for comparing Neandertal and modern human behavior is that both groups lived under comparable climate and environmental conditions at this locale (cold temperatures and open habitat).
They also had the same prey animals available to them, such as reindeer and horse.
Hardy examined the Mousterian and Aurignacian implements under a microscope, looking at their wear patterns and searching for residues from the substances with which the tools came into contact.
He found that although the modern humans created a larger variety of tools than did the Neanderthals, the groups engaged in mostly the same activities.
These activities include using tree resin to bind stone points to wooden handles, employing stone points as thrusting or projectile weapons, crafting implements from bone and wood, butchering animals and scraping hides.
According to the researchers, perhaps Neanderthals did not bother inventing additional tool types because they were able to get the job done just fine without them.
“Neanderthals stuck around for 150,000 years. That’s not a species that doesn’t know what it’s doing,” said Hardy.
As to how did the Neanderthals ultimately disappear, Hardy is of the opinion that it could just be that modern humans had a slight reproductive advantage that, over thousands of years, allowed their population to swamp the Neanderthal one. (ANI)
Why insomnia leads to weight gain
March 26, 2009 By Leave a Comment
Washington, Mar 26 (ANI): Insomnia has previously been linked to poor health, including weight gain. Now, a new study has revealed why.
Sarosh Motivala, an assistant professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and colleagues looked at two hormones that are primarily responsible for regulating the body’s energy balance, telling the body when it is hungry and when it is full.
They found that chronic insomnia disrupts one of these two hormones.
Till date, no study has evaluated nocturnal levels of the two hormones, ghrelin and leptin, in primary insomnia patients.
Ghrelin, a peptide secreted by the stomach, stimulates appetite and increases before meals.
Leptin, which affects body weight and is secreted primarily by fat cells, signals the hypothalamus regarding the degree of fat storage in the body; decreased leptin tells the body there is a calorie shortage and promotes hunger, while increased levels promote energy expenditure.
For the study, researchers compared healthy sleepers with those suffering from chronic insomnia and measured the levels of the two hormones at various times throughout the night.
They found that while leptin levels averaged out over the night to be roughly the same between the two groups, levels of ghrelin were 30 percent lower in insomnia sufferers.
On the face of it, a decreased level of ghrelin would seem to inhibit weight gain; it is an increase in ghrelin, after all, that stimulates appetite.
But Motivala compared his findings with other, earlier studies on sleep deprivation and speculates that a switch may occur during the day: Sleep loss leads to increased ghrelin and decreased leptin, a “double whammy” that stimulates appetite. Motivala is currently working on a study to examine this switch.
“The current study shows that insomnia patients have a dysregulation in energy balance that could explain why these patients gain weight over time,” said Motivala, who is also a member of the Cousins Center for Psychoneuroimmunology at UCLA.
The study is to be published in the May issue of the journal Psychoneuroendocrinology and is currently available online by subscription. (ANI)