Brain tweak turns wimpy mice into dominant leadersDominant mice can be humbled and wimps made mighty by altering the strength of electrical connections in their brain.
The crucial connections dictating a mouse's place in the social hierarchy appear to sit in the part of the brain called the medial prefrontal cortex (mPFC), responsible for emotion and decision-making.
To investigate the impact of the mPFC on social ranking, Hailan Hu of the Chinese Institute of Neuroscience in Shanghai and her colleagues first worked out the social hierarchy of mice through challenges between pairs of the animals in transparent tubes. When the mice came face to face, the subordinate animal would retreat and back out of the tube.
The team then injected a virus into some of the mice that inserts a gene called GluR4 into mPFC neurons. GluR4 amplifies transmission of electrical signals ? a key step in strengthening connections.
Up the ladder
When the dominance tests were repeated, previously subordinate mice that had received the virus were propelled to the top of the social ladder.
"These mice also tended to gain more food in competition with their cage-mates, mark more territories and sing more courtship songs than their subordinate counterparts," says Hu.
Hu's team then took brain slices from the mice in order to measure the electrical currents produced from mPFC neurons. Mice that had received the virus had mPFC connections almost twice as strong as those in control mice.
And back down
Another virus that implanted a gene called R4Ct ? that reduces transmission of electrical signals ? into the mPFC reduced connections between neurons to 71 per cent of their strength in control mice. Previously dominant mice who received this treatment became subordinate.
Interesting stuff. Somebody is going to try and market this for sure.
Devious, treacherous, murderous, neanderthal, sub-human of the West.