Bumblebees are anything but bumbling: The insects quickly figure out the optimal route for visiting five far-flung flowers, a computational task that even human brains find challenging.

That result suggests that an elaborate mental map isn’t necessary to travel efficiently in unknown territory. Finding a way to mimic the bumblebee’s navigation system may allow programmers to develop robots that adeptly maneuver through unfamiliar places.

The new study, published online September 20 in PLOS Biology, pulls together several lines of previous research into one grand experiment. After training bumblebees to associate artificial flowers with a reward, scientists from the University of Sydney, Rothamsted Research in Harpenden, England and Queen Mary University of London arranged five flowers in a pentagon with sides 50 meters long. One at a time, bumblebees outfitted with a little radar antenna were released from the nest. The bees’ movements were tracked by radar, and motion-sensing cameras on the flowers recorded each visiting bee.

A computer analysis of the bees’ movements suggested that the insects were doing some quick comparing. If a bee went from flower A to B and later went from flower A to C, it would compare those routes, adding the one that was shorter to its itinerary and abandoning longer paths. The bees also made adjustments when a flower was moved to a different location. These results suggest that bees don’t need a big-picture map to search their surroundings, says team member Mathieu Lihoreau, a behavioral ecologist at the University of Sydney.

“It’s amazing that these little creatures are as flexible as they are and have evolved these solutions that make maximum use of these little brains they are carrying around,” says behavioral biologist Fred Dyer of Michigan State University in East Lansing.

Study suggests that a poor sense of smell may be a marker for psychopathic traits.

People with psychopathic tendencies have an impaired sense of smell, which points to inefficient processing in the front part of the brain [orbitofrontal cortex]. These findings by Mehmet Mahmut and Richard Stevenson, from Macquarie University in Australia, are published online in Springer’s journal Chemosensory Perception.

Psychopathy is a broad term that covers a severe personality disorder characterized by callousness, manipulation, sensation-seeking and antisocial behaviors, traits which may also be found in otherwise healthy and functional people. Studies have shown that people with psychopathic traits have impaired functioning in the front part of the brain – the area largely responsible for functions such as planning, impulse control and acting in accordance with social norms. In addition, a dysfunction in these areas in the front part of the brain is linked to an impaired sense of smell.

Mahmut and Stevenson looked at whether a poor sense of smell was linked to higher levels of psychopathic tendencies, among 79 non-criminal adults living in the community. First they assessed the participants’ olfactory ability as well as the sensitivity of their olfactory system. They also measured subjects’ levels of psychopathy, looking at four measures: manipulation; callousness; erratic lifestyles; and criminal tendencies. They also noted how much or how little they emphasized with other people’s feelings.

The researchers found that those individuals who scored highly on psychopathic traits were more likely to struggle to both identify smells and tell the difference between smells, even though they knew they were smelling something. These results show that brain areas controlling olfactory processes are less efficient in individuals with psychopathic tendencies.

Plasticity of Inhibition

Until recently, the study of plasticity of neural circuits focused almost exclusively on potentiation and depression at excitatory synapses on principal cells. Other elements in the neural circuitry, such as inhibitory synapses on principal cells and the synapses recruiting interneurons, were assumed to be relatively inflexible, as befits a role of inhibition in maintaining stable levels and accurate timing of neuronal activity. It is now evident that inhibition is highly plastic, with multiple underlying cellular mechanisms. This Review considers these recent developments, focusing mainly on functional and structural changes in GABAergic inhibition of principal cells and long-term plasticity of glutamateric recruitment of inhibitory interneurons in the mammalian forebrain. A major challenge is to identify the adaptive roles of these different forms of plasticity, taking into account the roles of inhibition in the regulation of excitability, generation of population oscillations, and precise timing of neuronal firing.

How do language families evolve over many thousands of years? How stable over time are structural features of languages? Dan Dediu and Stephen Levinson from the Max Planck Institute for Psycholingustics in Nijmegen introduced a new method using Bayesian phylogenetic approaches to analyse the evolution of structural features in more than 50 language families. Their paper ‘Abstract profiles of structural stability point to universal tendencies, family-specific factors, and ancient connections between languages’ was published online on September 20, 2012 in PLoS ONE.

Brain study reveals the roots of chocolate temptations

Researchers have new evidence in rats to explain how it is that chocolate candies can be so completely irresistible. The urge to overeat such deliciously sweet and fatty treats traces to an unexpected part of the brain and its production of a natural, opium-like chemical, according to a report published online on September 20th in Current Biology, a Cell Press publication.

"This means that the brain has more extensive systems to make individuals want to overconsume rewards than previously thought," said Alexandra DiFeliceantonio of the University of Michigan, Ann Arbor. "It may be one reason why overconsumption is a problem today."

DiFeliceantonio’s team made the discovery by giving rats an artificial boost with a drug delivered straight to a brain region called the neostriatum. Those animals gorged themselves on more than twice the number of M&M chocolates than they would otherwise have eaten. The researchers also found that enkephalin, the natural drug-like chemical produced in that same brain region, surged when rats began to eat the candy-coated morsels, too.

It’s not that enkephalins or similar drugs make the rats like the chocolates more, the researchers say, but rather that the brain chemicals increase their desire and impulse to eat them.

The findings reveal a surprising extension of the neostriatum’s role, as DiFeliceantonio notes that the brain region had primarily been linked to movement. And there is reason to expect that the findings in rats can tell us a lot about our own binge-eating tendencies.

"The same brain area we tested here is active when obese people see foods and when drug addicts see drug scenes," she says. "It seems likely that our enkephalin findings in rats mean that this neurotransmitter may drive some forms of overconsumption and addiction in people."

The researchers now hope to unravel a related phenomenon that some of us might wish we could do more to control: what happens in our brains when we pass by our favorite fast food restaurant and feel that sudden desire to stop.

Fear can be erased from the brain

Newly formed emotional memories can be erased from the human brain. This is shown by researchers from Uppsala University in a new study now being published by the academic journal Science. The findings may represent a breakthrough in research on memory and fear. Thomas Ågren, a doctoral candidate at the Department of Psychology under the supervision of Professors Mats Fredrikson and Tomas Furmark, has shown, that it is possible to erase newly formed emotional memories from the human brain.

When a person learns something, a lasting long-term memory is created with the aid of a process of consolidation, which is based on the formation of proteins. When we remember something, the memory becomes unstable for a while and is then restabilized by another consolidation process. In other words, it can be said that we are not remembering what originally happened, but rather what we remembered the last time we thought about what happened. By disrupting the reconsolidation process that follows upon remembering, we can affect the content of memory.

New gene-therapy approach could improve obesity treatment

Medical researchers at the University of Alberta have found a new way of using gene therapy to treat obesity. The treatment was successful, resulting in less weight gain, higher activity levels and decreased insulin resistance in lab models on a high-fat, high-sugar diet.

Faculty of Medicine & Dentistry researcher Jason Dyck, who works in the Department of Pediatrics and the Department of Pharmacology, published his findings this week in the peer-reviewed journal Nutrition and Diabetes. His team found a way to deliver the obesity treatment via DNA as opposed to a virus, which has had limited success in the past, especially over the long term. The results they demonstrated corroborated findings by other researchers who conducted short-term studies or used more risky methods of gene delivery.

“I think our findings may bring this treatment one step closer to clinical trials, as this approach appears to be much safer than conventional forms of gene therapy,” said Dyck.

The obesity treatment focused on increasing levels of adiponectin, a hormone secreted from fat cells. As a person gains weight and fat cells get larger, the body secretes less of this hormone. People who are thin secrete high levels of this hormone.

“This hormone seems to be protective against a number of diseases, including diabetes and cardiovascular disease, as well as weight gain,” says Dyck. “But as you gain weight, less adiponectin is secreted and you lose the beneficial effects associated with this hormone.”

Lab animal models fed a high-fat, high-sugar diet that were given this treatment gained less weight, burned more calories, were more active, used more oxygen, and were better protected against glucose intolerance and insulin resistance than those that were fed the same diet but didn’t get the anti-obesity treatment. Dyck hopes other research teams will move his work forward.

Dyslexia Impairs Speech Recognition but Can Spare Phonological Competence

Dyslexia is associated with numerous deficits to speech processing. Accordingly, a large literature asserts that dyslexics manifest a phonological deficit. Few studies, however, have assessed the phonological grammar of dyslexics, and none has distinguished a phonological deficit from a phonetic impairment. Here, we show that these two sources can be dissociated. Three experiments demonstrate that a group of adult dyslexics studied here is impaired in phonetic discrimination (e.g., ba vs. pa), and their deficit compromises even the basic ability to identify acoustic stimuli as human speech. Remarkably, the ability of these individuals to generalize grammatical phonological rules is intact. Like typical readers, these Hebrew-speaking dyslexics identified ill-formed AAB stems (e.g., titug) as less wordlike than well-formed ABB controls (e.g., gitut), and both groups automatically extended this rule to nonspeech stimuli, irrespective of reading ability. The contrast between the phonetic and phonological capacities of these individuals demonstrates that the algebraic engine that generates phonological patterns is distinct from the phonetic interface that implements them. While dyslexia compromises the phonetic system, certain core aspects of the phonological grammar can be spared.

Neuroscientists Investigate Lotteries to Study How the Brain Evaluates Risk

People are faced with thousands of choices every day, some inane and some risky. Scientists know that the areas of the brain that evaluate risk are the same for each person, but what makes the value assigned to risk different for individuals?

To answer this question, a new video article in Journal of Visualized Experiments (JoVE) uses functional magnetic resonance imaging (fMRI) to characterize subjective risk assessment while subjects choose between different lotteries to play.

The article, a joint effort from laboratories at Yale School of Medicine and New York University, is led by Yale’s Dr. Ifat Levy. Dr. Levy explains, “This procedure allows us to examine all kinds of normal and pathological behaviors focusing on risk assessment. It could explain things like substance abuse and over-eating from a different perspective than how it is usually characterized.”

Neuroscientists are trying to work out why the brain does so much when it seems to be doing nothing at all.

For volunteers, a brain-scanning experiment can be pretty demanding. Researchers generally ask participants to do something — solve mathematics problems, search a scene for faces or think about their favoured political leaders — while their brains are being imaged.

But over the past few years, some researchers have been adding a bit of down time to their study protocols. While subjects are still lying in the functional magnetic resonance imaging (fMRI) scanners, the researchers ask them to try to empty their minds. The aim is to find out what happens when the brain simply idles. And the answer is: quite a lot.

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