Reports trumpeting basic differences between male and female brains are biological determinism at its most trivial, says the science writer of the year

As hardy perennials go, there is little to beat that science hacks' favourite: the hard-wiring of male and female brains. For more than 30 years, I have seen a stream of tales about gender differences in brain structure under headlines that assure me that from birth men are innately more rational and better at map-reading than women, who are emotional, empathetic multi-taskers, useless at telling jokes. I am from Mars, apparently, while the ladies in my life are from Venus.

The Republic (Greek: Πολιτεία, Politeia) is a Socratic dialogue, written by Plato around 380 BC, concerning the definition of justice and the order and character of the just city-state and the just man. It is Plato's best-known work and has proven to be one of the most intellectually and historically influential works of philosophy and political theory. In it, Socrates along with various Athenians and foreigners discuss the meaning of justice and examine whether or not the just man is happier than the unjust man by considering a series of different cities coming into existence "in speech", culminating in a city (Kallipolis) ruled by philosopher-kings; and by examining the nature of existing regimes. The participants also discuss the theory of forms, the immortality of the soul, and the roles of the philosopher and of poetry in society.

In The Republic Plato describes four types of government - monarchy, oligarchy, tyranny, and democracy. The Allegory of the Cave is a discussion on human mentality and the body politic, our thinking and being. There are four types of people in the cave, though nowhere in the text are the characters overtly counted. In the cave there are the captors and captives. The captives in the cave are controlled and know nothing in life but the cave, worse they only know one wall of the cave. The captors use a fire to cast shadows on the wall the prisoners face to keep them captivated and distracted by a made up reality. Among the captives there are the chained and the unchained. The chained are held in place so that they can only look straight ahead and are convinced of the reality and moreover importance of the shadows. The unchained are transfixed with the images and convinced of the reality and moreover the importance of the shadows to the point they don't need chains. They are held by shadows, like elephants onto a string. Both the chained and unchained captives have no interest in their actual existence as captives in a cave. They are not conscious, they are not aware of self or their surroundings, or the captors, they are only aware of and concerned with the shadows.

"Sticks and stones may break my bones, but words will never hurt me," goes the playground rhyme that's supposed to help children endure taunts from classmates. But a new study suggests that there's more going on inside our brains when someone snubs us -- and that the brain may have its own way of easing social pain. The findings, recently published in Molecular Psychiatry by a University of Michigan Medical School team, show that the brain's natural painkiller system responds to social rejection -- not just physical injury.

What's more, people who score high on a personality trait called resilience -- the ability to adjust to environmental change -- had the highest amount of natural painkiller activation.

The team, based at U-M's Molecular and Behavioral Neuroscience Institute, used an innovative approach to make its findings. They combined advanced brain scanning that can track chemical release in the brain with a model of social rejection based on online dating. The work was funded by the U-M Depression Center, the Michigan Institute for Clinical and Health Research, the Brain & Behavior Research Foundation, the Phil F Jenkins Foundation, and the National Institutes of Health.

They focused on the mu-opioid receptor system in the brain -- the same system that the team has studied for years in relation to response to physical pain. Over more than a decade, U-M work has shown that when a person feels physical pain, their brains release chemicals called opioids into the space between neurons, dampening pain signals.

Behaviour can be affected by events in previous generations which have been passed on through a form of genetic memory, animal studies suggest.

Experiments showed that a traumatic event could affect the DNA in sperm and alter the brains and behaviour of subsequent generations.

A Nature Neuroscience study shows mice trained to avoid a smell passed their aversion on to their "grandchildren".

Experts said the results were important for phobia and anxiety research.

The animals were trained to fear a smell similar to cherry blossom.

The team at the Emory University School of Medicine, in the US, then looked at what was happening inside the sperm.

They showed a section of DNA responsible for sensitivity to the cherry blossom scent was made more active in the mice's sperm.

Both the mice's offspring, and their offspring, were "extremely sensitive" to cherry blossom and would avoid the scent, despite never having experienced it in their lives.

Changes in brain structure were also found.

Dyslexia, the learning disability that makes reading and processing speech a challenge, may result from problems with brain connectivity, a new study suggests.

Scientists estimate that dyslexia affects more than 10 percent of the world's population. Some hypothesize that in people with dyslexia, the way that speech sounds are represented in the brain is impaired, while others contend that the brains of people with dyslexia represent the sounds correctly, but have trouble accessing them because of faulty brain connections.

Ultimately, understanding the roots of dyslexia could lead to better ways to help people with the disability, the researchers said.

Normally, when people read words or hear spoken language, the brain creates a map to represent the basic sounds in speech, called phonemes. These brain representations have to be robust, for instance, all "b" sounds must map to the same category.

But they must also be distinct, in order to distinguish between similar sounds such as "b" and "d." In the new study, Bart Boets, a clinical psychologist at KU Leuven, in Belgium, and his colleagues used brain imaging to test which hypothesis - flawed sound representations or flawed wiring - best explains dyslexia.

The researchers scanned the brains of 23 adults with dyslexia and 22 adults without the condition as they responded to various speech stimuli. The scientists looked at how accurately the participants' brains mapped sounds to their phonetic representations.

People with dyslexia had intact representations of basic sounds, just as non-dyslexic people did, the scans revealed.

A new paper published in Biological Psychiatry suggests that cognitive behavioral therapy for posttraumatic stress disorder (PTSD) not only reduces symptoms but also affects the underlying biology of this disorder.

The researchers, led by Dr. Szabolcs Kéri at the National Institute of Psychiatry and Addictions and University of Szeged in Hungary, recruited 39 individuals diagnosed with PTSD to participate in the study. For a comparison group, they also included 31 individuals who had been exposed to trauma, but who did not develop PTSD. The individuals with PTSD then received 12 weeks of cognitive behavioral therapy, whereas the non-PTSD group received no therapy.

Before and after the 12 weeks, the researchers measured the volumes of certain brain regions using magnetic resonance imaging. They also collected blood samples to measure changes in expression of a specific gene, FKBP5, which has been implicated in the risk for developing PTSD and plays a role in regulating stress hormones.

Researchers have struggled to identify how certain states of mind influence physical health. One biologist thinks he has an answer.

When Steve Cole was a postdoc, he had an unusual hobby: matching art buyers with artists that they might like. The task made looking at art, something he had always loved, even more enjoyable. "There was an extra layer of purpose. I loved the ability to help artists I thought were great to find an appreciative audience," he says.

At the time, it was nothing more than a quirky sideline. But his latest findings have caused Cole - now a professor at the Cousins Center for Psychoneuroimmunology at the University of California, Los Angeles - to wonder whether the exhilaration and sense of purpose that he felt during that period might have done more than help him to find homes for unloved pieces of art. It might have benefited his immune system too.

At one time, most self-respecting molecular biologists would have scoffed at the idea. Today, evidence from many studies suggests that mental states such as stress can influence health. Still, it has proved difficult to explain how this happens at the molecular level - how subjective moods connect with the vastly complex physiology of the nervous and immune systems. The field that searches for these explanations, known as psychoneuroimmunology (PNI), is often criticized as lacking rigour. Cole's stated aim is to fix that, and his tool of choice is genome-wide transcriptional analysis: looking at broad patterns of gene expression in cells. "My job is to be a hard-core tracker," he says. "How do these mental states get out into the rest of the body?"

Men aren't from Mars and women aren't from Venus, but their brains really are wired differently, a new study suggests.

The research, which involved imaging the brains of nearly 1,000 adolescents, found that male brains had more connections within hemispheres, whereas female brains were more connected between hemispheres. The results, which apply to the population as a whole and not individuals, suggest that male brains may be optimized for motor skills, and female brains may be optimized for combining analytical and intuitive thinking.

"On average, men connect front to back [parts of the brain] more strongly than women," whereas "women have stronger connections left to right," said study leader Ragini Verma, an associate professor of radiology at the University of Pennsylvania medical school. But Verma cautioned against making sweeping generalizations about men and women based on the results.

Scientists have shown for the first time that fear can be transmitted from a father to his offspring through his sperm alone in a ground-breaking study into a new kind of genetic inheritance.

Experiments on mice have demonstrated that they can be trained to associate a particular kind of smell to a fearful memory and that this fear can be passed down through subsequent generations via chemical changes to a father's sperm cells.

The findings raise questions over whether a similar kind of inheritance occurs in humans, for example whether men exposed to the psychological trauma of a foreign war zone can pass on this fearful behavioural experience in their sperm to their children and grandchildren conceived at home.

The researchers emphasised that their carefully controlled study was carried out on laboratory mice and there are still many unanswered questions, but they do not discount the possibility that something similar may also be possible in people.

"I think there is increasing evidence from a number of studies that what we inherit from out parents is very complex and that the gametes - the sperm and eggs - may be a possible mechanism of conserving as much information as possible from a previous generation," said Kerry Ressler, professor of psychiatry at Emory School of Medicine in Atlanta, Georgia.

Unravelling how brain reacts to the sounds of dentists' drills could help scientists put anxious patients more at ease.

The whir of a dentist's drill might bring on the shakes and a racing heart, but what happens in the brain has long been a mystery.

Now researchers in Japan believe they are closer to an answer after scanning people's brains while playing them sounds of dental drills and suction instruments.

People who were terrified of visits to the dentist showed marked differences in their brain responses compared with those who were more relaxed at the prospect, according to work reported at the Society for Neuroscience meeting in San Diego on Sunday.

Unravelling how the brain reacts to the sounds, particularly in the most anxious dental patients, could help scientists assess different ways to make patients more at ease, by seeing how they alter neural activity, said Hiroyuki Karibe at Nippon Dental University in Tokyo.