Women's Brains Recognize, Encode Smell Of Male Sexual Sweat

A new Rice University study published in the Journal of Neuroscience found that socioemotional meanings, including sexual ones, are conveyed in human sweat.

Denise Chen, assistant professor of psychology at Rice, looked at how the brains of female volunteers processed and encoded the smell of sexual sweat from men. The results of the experiment indicated the brain recognizes chemosensory communication, including human sexual sweat.

Scientists have long known that animals use scent to communicate.

Chen's study represents an effort to expand knowledge of how humans’ sense of smell complement their more powerful senses of sight and hearing.

The experiment directly studied natural human sexual sweat using functional magnetic resonance imaging (fMRI). Nineteen healthy female subjects inhaled olfactory stimuli from four sources, one of which was sweat gathered from sexually aroused males.

The research showed that several parts of the brain are involved in processing the emotional value of the olfactory information. These include the right fusiform region, the right orbitofrontal cortex and the right hypothalamus.

"With the exception of the hypothalamus, neither the orbitofrontal cortex nor the fusiform region is considered to be associated with sexual motivation and behavior," Chen said. "Our results imply that the chemosensory information from natural human sexual sweat is encoded more holistically in the brain rather than specifically for its sexual quality."

Humans are evolved to respond to salient socioemotional information.

Distinctive neural mechanisms underlie the processing of emotions in facial and vocal expressions. The findings help explain the neural mechanism for human social chemosignals.

The understanding of human smell at the neural level is still at the beginning stage. The present work is the first fMRI study of human social chemosignals.

The research, co-authored by Chen and Wen Zhou, graduate student in the Psychology Department, appeared in the December 31 issue of Journal of Neuroscience.

The research was supported in part by the National Institutes of Health.

Antipsychotic Drugs Double Risk Of Death Among Alzheimer's Patients

New research into the effects of antipsychotic drugs commonly prescribed to Alzheimer’s patients concludes that the medication nearly doubles risk of death over three years.

The study, funded by the Alzheimer’s Research Trust, was led by Prof Clive Ballard’s King’s College London team and is published in Lancet Neurology on 9 January.

The study involved 165 Alzheimer’s patients in care homes who were being prescribed antipsychotics. 83 continued treatment and the remaining 82 had it withdrawn and were instead given oral placebos.

Findings showed a significant increase in risk of death for patients who continued taking antipsychotic medication. The difference between the two groups became more pronounced over time, with 24-month survival rates for antipsychotic-treated patients falling to 46% versus 71% on the placebo and at 36 months it was 30% versus 59%. It means that after three years, less than a third of people on antipsychotics were alive compared to nearly two thirds using the dummy drug.

Antipsychotics are used to treat symptoms of agitation, delusions and aggressive behaviour. NICE guidelines recommend that the drugs should only be used for short periods of time and where symptoms are severe, and should be very carefully monitored, although in clinical practice the average length of prescription is 1-2 years. While there is evidence of modest short-term (6-12 weeks) benefits of antipsychotic treatment for the serious behavioural symptoms of Alzheimer’s, a previous Alzheimer’s Research Trust study showed that these benefits were not evident over longer periods of treatment.

As many as 100,000 people with dementia are routinely prescribed antipsychotics in UK care homes. It could mean 23,500 people dying prematurely, according to a 2008 report by Paul Burstow MP.

Prof Clive Ballard of King’s College London said: “The results further highlight the need to seek less harmful alternatives for the long-term treatment of behavioural symptoms in Alzheimer’s patients. At the moment, there is still a limited place for antipsychotics in the treatment of Alzheimer’s, particularly severe aggression, but the serious concerns of the drugs shown by our research emphasise the urgent need to put an end to unnecessary and prolonged prescribing”.

Rebecca Wood, Chief Executive of the Alzheimer’s Research Trust, said: “The findings of this research are a real wake-up call and underline the danger of prescribing antipsychotics long-term for anything other than exceptional circumstances. We must avoid the use of these drugs as a potentially dangerous ‘chemical cosh’ to patients who would be better off without it. The study also highlights the urgent need to develop better treatments as Alzheimer’s patients have few options available to them.

"700,000 people in the UK have dementia; we urgently need to fund more research to develop the new treatments we so desperately need”.

Dr Mark Baxter of the University of Oxford added: "Antipsychotic drugs can be effective in controlling unpleasant and disturbing behavioural symptoms of Alzheimer's disease, including severe aggression, delusions, and agitation. But this study shows, conclusively, that these drugs have a severe and serious cost in terms of increased mortality. The study follows the gold-standard double-blind, placebo-controlled method for clinical trials, and is unique in examining long-term effects of antipsychotic treatment on mortality in patients with Alzheimer's disease.

"Antipsychotics do not have any effects on the underlying disease processes of Alzheimer's disease. What is needed is not only an increased application of non-drug methods to improve behavioural health in patients with dementia -- including cognitive-behavioural therapy and environmental design -- as well as a better understanding of how Alzheimer's neuropathology causes behavioural disturbances in addition to its effects on memory, so that rational drug therapies can be developed that do not have the liabilities of currently-available antipsychotics."