Wiring the Brain

Male and female brains are wired differently.   That is not intended metaphorically – they literally have different amounts and/or patterns of axonal connections between a variety of brain regions, as well as differences in the size or number of cells in various regions.   This is true in mammals, birds, fish, even insects and correlates with hard-wired, innate differences in behaviour between the sexes across in species across all these phyla.   This is as true for humans as for any other species.   The behaviours that show the most robust and innate differences between the sexes are involved in mating, reproduction, parental behaviour, territoriality and aggression and it is the brain areas that control these behaviours that are the most obviously sexually dimorphic (showing a difference in size or morphology between the sexes).   In mammals, these include areas in the limbic system, including parts of the hypothalamus, amygdala, preoptic area and bed nucleus of the stria terminali

Faces are special.   Humans are innately interested in faces and so good at detecting them that we see them in clouds, shrouds, pieces of toast, tree-stumps, and even simple yellow circles with a couple of dots in them.   Even newborn infants (really, really newborn) are more interested in looking at faces than non-faces.   Not too surprisingly, this preference and ability extends to other species too.   Monkeys reared from birth with absolutely no visual exposure to either monkey or human faces for two years still showed a strong preferential interest in faces (both monkey and human) when they were shown them.   Given the importance within social groups of recognising particular individuals and of reading emotional and social cues from people’s faces, it is perhaps not too surprising that face recognition is a built-in part of our cognitive toolkit.    This is not to say that experience plays no part in the skill of face recognition – we clearly improve with practice and exposure in

The mighty mouse has become an invaluable tool in biomedical research, due to the fact that its genome can readily be manipulated, using genetic engineering techniques in embryonic stem cells.   These techniques were first developed to “knock out” or delete any gene in the mouse genome and this approach is so established now that off-the-shelf knockouts for most genes in the genome are already available from several centres .   Genetic technologies have become increasingly sophisticated, giving researchers the ability to remove a gene’s function in just some cells in an animal or just at specific stages of development and also to engineer larger sections of chromosomes so that deletions or duplications that affect multiple genes can be modeled in the mouse.   These genetic approaches have been used extremely successfully to model a vast number of human medical conditions in the mouse, following a simple pathway from the discovery of mutations associated with the disorder in humans to t