Mind Hacks

Although headaches are a traditional turn-off for amorous couples, new research published in the journal Headache suggests that people susceptible to migraines actually report greater levels of sexual desire.

The authors suggest that the link may be levels of the neurotransmitter serotonin – which are linked to libido and have also been found to increase during migraine onset.

Luckily, greater levels of sexual desire tend to be a general trait in those susceptible to migraine, rather than being linked to the experience of headache itself.

Link to study abstract.

Science have an interesting snippet on a study that shows that shy children may not only be more sensitive to unpleasant things, and also to pleasurable and rewarding experiences as well.

A brain scanning study led by Dr Amanda Guyer showed that areas of the brain sensitive to both anxiety and reward were more strongly activated in shy children than other children.

The study subjects – who were classified as either shy or outgoing based on psychological testing – were instructed to press a button as quickly as possible after being shown a signal. If they pressed the button in time, they won money, or at least prevented themselves from losing it.

Both groups performed similarly, and there was no difference in the activity of their amygdalas – the brain region that governs fear. Shy children, however, showed two to three times more activity in their striatum, which is associated with reward, than outgoing children, the team reports in the 14 June issue of the Journal of Neuroscience. “Up until now, people thought that [shyness] was mostly related to avoidance of social situations,” says co-author and child psychiatrist Monique Ernst. “Here we showed that shy children have increased activity in the reward system of the brain as well.”

Link to article ‘The Rewards of Being Shy’.
Link to study abstract.

A recent study examining how the brain reacts to different types of image has found that women show a quicker reaction to erotic images than other image types. This is the first time that a difference in brain activity for erotic images has been found in women.

The research was led by neuroscientist Andrey Anokhin and used a technique that measures electrical activity from the brain by recording event-related potentials or ERP.

ERP is not very good at detecting which exact areas activity comes from, but can detect changes over very short periods of time (less than a millisecond). This makes it very good for determining differences in when the brain reacts.

Previous studies have found that men tend to show a stronger physiological response to erotic images than other images, as well as having larger areas of brain active when viewing such images.

Until now, no difference between erotic and non-erotic images had been found in women.

The study found that erotic images differently activated the mid part of the female prefrontal cortex (the red area in the image on the left) when compared to other images, within 185ms. Interestingly, this was regardless of how arousing or emotionally strong the images were.

185ms is an incredibly short time for the brain to differentiate between image types, and is almost certainly an automatic response. The prefrontal cortex is known to be involved in attention, and the authors suggest this activity reflects a vigiliance for socially relevant visual scenes.

When taken with the other research in the area, these findings suggests that men and women show differences in both where and when brain activity occurs when viewing erotic images.

However, it is still not clear what these differences might mean, and more extensive studies will need to be conducted to better understand this response.

It is also interesting that Anokhin and colleagues didn’t ask the female participants about sexual activity, orientation or a number of other things (such as stage in the menstrual cycle) that might affect reaction to erotic images.

It may be that these might have their own unique effect upon the new form of response reported in this study.

Link to study abstract.
Link to write-up from Live Science.

Transcranial magnetic stimulation (TMS) is a technique whereby magnetic fields are used to temporarily alter the function of the brain by inducing an electrical current in the brain tissue.

In neuroscience research, TMS usually refers to the use of powerful magnetic fields (about 1.5 tesla or 40,000 times the earth’s magnetic field) focused on approximately 1x1cm areas of the cortex.

Repetitive TMS (rTMS) can be used either to make the area more active or less active over a specific time period (often 30 minutes or so), while single pulse TMS is used to harmlessly ‘knock out’ an area for approximately 100ms.

Much weaker magnetic fields (about the strength of a loudspeaker) but much more complex in form, have also been used to induce unusual experiences by stimulating the temporal lobes, most notably by neuroscientist Dr Michael Persinger.

A new project called Open-rTMS aims to develop this latter type of system (actually, generally not referred to as TMS in the neuroscience literature) and publish the plans and software online.

They’re currently looking for people to sign up to the mailing list and kick the project off, so if you’re looking for a way to alter your state of consciousness with magnets, this might be your chance.

The project is similar in approach to the OpenEEG project, which aims to provide software and plans for a home EEG system, so you can read the brain’s electrical activity.

Link to Science News article on high-strength TMS.
Link to low-strength Open-rTMS project page.

New Scientist reports on a recent study that looks at the differences between epilepsy and psychogenic non-epileptic seizures – a mysterious condition that looks like a standard epileptic seizure (e.g. falling to the floor, limb shaking and unconsciousness) but does not seem to involve any disturbance in brain activity and instead is linked to underlying emotional issues and psychological distress.

It has been suggested that patients with psychogenic non-epileptic seizures consciously fake their attacks, but it now seems that although not related to a disturbance in brain function, the attacks are not under conscious control and seem to be related to conversion hysteria, where psychological stress leads to otherwise unexplained medical symptoms.

There’s more on these type of seizures in a previous post on Mind Hacks, for those that are interested.

A recent study by Dr Steve Chung and his colleagues attempted to distinguish between epileptic and non-epileptic seizures by carefully watching videos of people when they have a seizure.

They noticed that in genuine generalised epileptic seizures, the patients had their eyes open during the attack, whereas those with non-epileptic seizures had their eyes closed.

This can be seen in their video of a genuine epileptic seizure (WMV file) when compared to a non-epileptic seizure (WMA file).

The head and eye turning that occurs at the start of the genuine seizure is typical in some forms of epilepsy, and usually indicates that the seizure starts in the side of the brain opposite to the side of turning.

The ability to easily distinguish between seizure types is important, as genuine seizures are best treated with anti-epileptic drugs, whereas non-epileptic seizures can be treated with psychological therapy.

Link to New Scientist story.
Link to abstract of study from Neurology.
Link to previous Mind Hacks post on non-epileptic seizures.