Do you ever wonder why you always remember great sexual encounters for the rest of your life? Thank a pair of neurons that has been found to remember and seek sex even at the expense of food in male worms.
These male-specific neurons are required for sex-based differences in learning, suggesting that sex differences in cognitive abilities can be genetically hardwired.
“Areas of the brain involved in learning display sex differences in many animals, including humans, but how these differences directly affect behaviour is not clear,” said senior author Dr Arantza Barrios from University College London.
The team has shown how genetic and developmental differences between the two sexes lead to structural changes in the brain of male worms during sexual maturation.
“These changes make male brains work differently, allowing males to remember previous sexual encounters and prioritise sex in future situations,” he explained.
The team were surprised to find previously unidentified cells that are responsible for the behavioural change as worms are an extremely well studied model organism.
They were able to show that the cells from which these male brain neurons are born share common characteristics to the cells that give rise to human brain neurons.
They are glial cells -- companion and support cells of neurons.
The newly identified pair of neurons -- called ‘mystery cells of the male’ or “MCMs” - create behavioural differences between the sexes by changing a brain circuit common to both.
The “MCM” neurons are only made from glial cells that have male chromosomes.
“Though the work is carried out in a small worm, it nevertheless gives us a perspective that helps us understand the variety of human sexuality, sexual orientation and gender identification,” explained co-author professor Scott Emmons from Albert Einstein College of Medicine.
The scientists can now exploit this system to understand how fully differentiated glia can re-enter the cell cycle and generate neurons. This could have important therapeutic implications in the future.
The study was published in the journal Nature.