A really interesting read, I’d love to have a really acute sense of smell, mix up some of those olfactory nerves!
Brain scans now show that more of the brain is devoted to smell processing than Broca’s anatomical studies would have suggested. And although we may have fewer types of receptor than other mammals, Charles Greer at Yale University has shown that the human nose and brain are unusually well connected, with each group of receptors linking to many more neural regions than is the case in other animals. That should give us a good ability to process incoming scents.
Once researchers began looking, they found the nose to be far more sensitive than its reputation suggested. One study, for example, found that we can detect certain chemicals diluted in water to less than one part per billion. That means that a person can detect just a few drops of a strong odorant like ethyl mercaptan in an Olympic-sized pool.
We are also exceptionally gifted at telling smells apart, even distinguishing between two molecules whose only difference is that their structures are mirror images of one another. “That is fantastic sensitivity,” says George Dodd, a perfumer and researcher at the olfaction group of the University of Warwick, UK.
REM sleep could prompt life-saving decisions
A team of researchers at Belgium’s University of Liège have undertaken some hopeful research into brain wave activity of patients in comas as a result of serious brain injury. They looked to separate patients in such situations into more distinct groupings, be it the permanently vegetative state (where life support is generally terminated as there is no hope of recovery) or an alternative minimally conscious state (from which there is a greater chance of a better outcome).
The team used electroencephalography (EEG) to record the electrical activity of the brain in six minimally conscious and five vegetative people while they slept. These individuals had been diagnosed using traditional tests for reflex movements and responses to sounds and other stimuli.
Five of the six minimally conscious people exhibited brain-wave patterns that are typical of normal sleep, alternating between rapid eye movement (REM) and non-REM, or “slow-wave”, sleep during the night.
This research follows work from earlier this year by the same team, detailing brain activity responses corresponding to sounds, showing some level of brain function is retained in minimally conscious patients.
The use of detection of REM sleep in minimally conscious patients may be a long way off in terms of being diagnostically useful in determining patient outcomes, as Adrian Owen of University of Western Ontario in London, Canada, points out “It is certainly possible, but just because they show the same patterns of brain activity that are seen when healthy people dream does not necessarily mean they are dreaming.”.
Rare genetic mutation explains lack of fingerprints
Researchers have identified a mutation as a possible underlying cause of the condition known as adermatoglyphia or an absence of fingerprints.
Eli Sprecher and his colleagues at Tel Aviv University, Israel, studied three generations of a family with adermatoglyphia, resulting in the unveiling of a mutation in the gene SMARCAD1. Sprecher highlights the relevance of such a finding, as “without this family, we simply would not know what SMARCAD1 is,” he says; maintaining that studying the proteins generated by such new genes “may lead to the development of treatments for more common conditions”. (x)