Tag Archives: neuroscience

Scientists discover bees that can reverse brain aging

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By Maria Panagiotidi

Scientists at Arizona State University have discovered that older honey bees can reverse brain aging when they take on nest responsibilities typically handled by much younger bees.

This finding could provide alternative interventions for the treatment of age-related dementia. Current research focuses mainly on potential new drug treatments.

The study was published in the scientific journal Experimental Gerontology by a team of scientists from ASU and the Norwegian University of Life Sciences, led by Gro Amdam. The researchers found that tricking older, foraging bees into doing social tasks inside the nest causes changes in the molecular structure of their brains.

Previous research on honey bees has found that bees that stay in the nest and take care of larvae – the baby bees – remain mentally competent. However, after a period of nursing, bees fly out looking for food and begin aging very quickly. The effects of aging are visible after two weeks in the appearance of the foraging bees (worn wings, hairless bodies) and more importantly, in their brain function. Specifically, these bees lose the ability to learn new things.

Influenced by recent studies on brain plasticity, Amdam and colleagues wanted to see what would happen if the foraging bees returned to the nest and took care of the larval babies again.

The results of the experiment were fascinating. After 10 days, about 50 percent of the older bees caring for the nest and larvae had significantly improved their ability to learn new things.

The change observed in the older bees was not just behavioural but also physiological; Amdam and colleagues discovered a change in proteins in the bees’ brains. After comparing the brains of the bees that improved to those that did not, they found that two proteins had noticeably changed: Prx6 and “chaperone” protein. Both proteins have been previously found to protect the brain against diseases such as Alzheimer’s.

This finding could lead to the development of a drug that could help older people maintain brain function. However, many years of basic research and trials will be needed before such a drug becomes commercially available.

For now, Amdam and colleagues propose that social interventions might help our brains stay younger. Since the proteins being researched in people are the same as those found in bees, it is possible that these proteins may be able to respond to specific social experiences. Further research is needed on mammals in order to confirm that the same molecular changes occur on other species’ brains.

 

Reference

Nicholas Baker, Florian Wolschin, Gro V. Amdam. Age-related learning deficits can be reversible in honeybees Apis mellifera. Experimental Gerontology, 2012; DOI: 10.1016/j.exger.2012.05.011

Anxiety enhances sense of smell

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By Maria Panagiotidi

Anxious people have a heightened sense of smell, when it comes to sniffing out a threat, according to a new study by Elizabeth Krusemark and Wen Li from the University of Wisconsin-Madison in the US. The results of their study will be published online in the journal Chemosensory Perception.

The sense of smell is an essential tool for survival in animals. It allows them to detect, locate and identify predators in the surrounding environment. In fact, the olfactory-mediated defence system is so important in animals, that the mere presence of predator odours can evoke potent fear and anxiety responses.

Smells also evoke powerful emotional responses in humans. Krusemark and Li hypothesized that in humans, detection of a particular bad smell may signal danger of a noxious airborne substance, or a decaying object that carries disease. Also, they speculated that the level of response to the above could underlie phobias or anxiety related disorders.

The researchers tested their hypotheses by combining assessment of state-level anxiety, psychophysical testing, and functional magnetic resonance imaging (fMRI) techniques.  They recruited 14 young adult participants who were exposed to three types of odours: neutral pure odor, neutral odor mixture, and negative odor mixture. The participants were asked to detect the presence or absence of an odour in an MRI scanner. During scanning, the researchers also measured skin conductance response (a measure of arousal level), and monitored the subjects’ breathing patterns. After completing the odour detection task, the participants were asked to rate their current level of anxiety using a standardised clinical test.

The authors found that as anxiety levels rose, so did the subjects’ ability to discriminate negative odours accurately – suggesting a ‘remarkable’ olfactory acuity to threat in anxious subjects. The same pattern was found in the skin conductance results which showed that anxiety also heightened emotional arousal to smell-induced threats.

Krusemark and Li uncovered amplified communication between the sensory and emotional areas of the brain in response to negative odours, particularly in anxiety. This increased connectivity could be responsible for the heightened arousal to threats.

These findings could help researchers elucidate the aetiology of the unfortunate and debilitating symptoms that perpetuate anxiety disorders.

 

Reference:

Krusemark EA & Li W (2012). Enhanced olfactory sensory perception of threat in anxiety: an event-related fMRI study. Chemosensory Perception. DOI 10.1007/s12078-011-9111-7

You can find the article here: http://www.springerlink.com/content/a268t518p1x59v68/