For decades now, cigarette makers have marketed light cigarettes, which contain less nicotine than regular smokes, with the implication that they are less harmful to smokers' health. A new UCLA study shows, however, that they deliver nearly as much nicotine to the brain.
The basic numbers would seem to bear that out the less harmful claim. Light cigarettes have nicotine levels of 0.6 to 1 milligrams, while regular cigarettes contain between 1.2 and 1.4 milligrams.
In the brain, nicotine binds to specific molecules on nerve cells called nicotinic acetylcholine receptors, or nAChRs. When nerve cells communicate, nerve impulses jump chemically across gaps between cells called synapses by means of neurotransmitters. The neurotransmitters then bind to the receptor sites on nerve cells — in the case acetylcholine resulting in the release of a pleasure-inducing chemical called dopamine. Nicotine mimics acetylcholine, but it lasts longer, releasing more dopamine. Most scientists believe that's one key reason why nicotine is so addictive.
Scientists at Yale School of Medicine have found that two-year-olds with autism looked significantly more at the mouths of others, and less at their eyes, than typically developing toddlers. This abnormality predicts the level of disability, according to study results published in the Archives of General Psychiatry.
Lead author Warren Jones and colleagues Ami Klin and Fred Volkmar used eye-tracking technology to quantify the visual fixations of two-year-olds who watched caregivers approach them and engage in typical mother-child interactions, such as playing games like peek-a-boo.
Eight-year-old children have a much different learning strategy compared to twelve-year-olds and adults. Eight-year-olds learn primarily from positive feedback ('Well done!'), whereas negative feedback ('Got it wrong this time') scarcely causes any alarm bells to ring. Twelve-year-olds are better able to process negative feedback and learn from their mistakes. Adults do the same, but even more efficiently.
If your lover's singing is sometimes sexy and sometimes annoying, a change in hormones may be the reason.
A songbird study led by Donna Maney,assistant professor of psychology and a member of the Graduate Program in Neuroscience at Emory University, says it sheds new light on this issue, showing that a change in hormone levels may alter the way we perceive social cues by altering a system of brain nuclei, common to all vertebrates, called the "social behavior network."
Their research examines how genes, hormones and the environment interact to affect the brain, using songbirds as a model and helps provide an understanding of the basic principles underlying brain structure and function common to many species, including humans.
Imagine you can never do the simplest memory orientation task, like finding your way home from the grocery store. In a world where most of us take our ability to do 'cognitive mapping' of our environment for granted, being lost all of the time like that can be terrifying.
Writing in Neuropsychologia, a study led by Giuseppe Iaria, a University of British Columbia Faculty of Medicine and Vancouver Coastal Health Authority postdoctoral fellow, used functional magnetic resonance imaging (fMRI) together with behavioral studies to assess and characterize the navigational deficiencies of a patient who is completely unable to orient within any environment, getting lost even within the neighborhood where the patient lived for many years.
How you react physically to stimuli can have a great deal of impact on how you perceive the world and therefore how you vote, according to a recent study by researchers at the University of Nebraska-Lincoln (UNL).
For example, people who react more strongly to bumps in the night, spiders on a human body or the sight of a shell-shocked victim are more likely to support public policies that emphasize protecting society over preserving individual privacy. The research results appear in the Sept. 19 issue of Science magazine.
The study tested 46 people who identified themselves as having strong political opinions. Researchers showed subjects threatening visual images--pictures of a spider on a person's eyeball, a dazed person with a bloody face and an open wound with maggots in it--and monitored their skin for electrical conductivity, which indicates emotion, arousal and attention. In another physiological measure, the scientists surprised subjects with a sudden, jarring noise and measured how hard they blinked in response to being startled.
The superior colliculus has long been thought of as a rapid orienting center of the brain that allows the eyes and head to turn swiftly either toward or away from the sights and sounds in our environment. Now a team of scientists at the Salk Institute for Biological Studies has shown that the superior colliculus does more than send out motor control commands to eye and neck muscles.
Two complementary studies, both led by Richard Krauzlis, Ph.D., an associate professor in the Systems Neurobiology Laboratory at the Salk Institute, have revealed that the superior colliculus performs supervisory functions in addition to the motor control it has long been known for. The results are published in the Aug. 6 and Sept. 17 issues of the Journal of Neuroscience.
"Beyond its classic role in motor control, the primate superior colliculus signals to other brain areas the location of behaviorally relevant visual objects by providing a 'neural pointer' to these objects," says Krauzlis.
When we hear somebody described as “frosty” or “cold”, we automatically picture a person who is unfriendly and antisocial. There are numerous examples in our daily language of metaphors which make a connection between cold temperatures and emotions such as loneliness, despair and sadness.
We are taught at a young age that metaphors are meant to be descriptive and are not supposed to be taken literally but recent studies suggest that these metaphors are more than just fancy literary devices and that there is a psychological basis for linking cold with feelings of social isolation.
MIT neuroscientists have tricked the visual brain into confusing one object with another, demonstrating that time teaches us how to recognize objects. This discovery, they say, could lead to robots with actual 'recognition' ability.
It may sound strange, but human eyes never see the same image twice. An object such as a cat can produce innumerable impressions on the retina, depending on the direction of gaze, angle of view, distance and so forth. Every time our eyes move, the pattern of neural activity changes, yet our perception of the cat remains stable.
A possible explanation is suggested by the fact that our eyes tend to move rapidly (about three times per second), whereas physical objects usually change more slowly. Therefore, differing patterns of activity in rapid succession often reflect different images of the same object. Could the brain take advantage of this simple rule of thumb to learn object invariance?
We all know that people can be influenced in complex ways by their peers. But two new studies in the September 11th issue of Current Biology reveal that the same can also be said of fruit flies.
The researchers found that group composition affects individual flies in several ways, including changes in gene activity and sexual behavior, all mediated by chemical communication.