New Study Reveals 'Wiring' Differences Between Men and Women

A study recently published in the journal NeuroImage has reported widespread differences between men and women in the way neural circuits are put together. The article (click here) which utilizes a brain imaging technique known as diffusion tensor imaging (DTI) was conducted to characterize the differences between the white matter (made predominantly of myelin which serves to insulate the neurons). DTI is commonly used to examine the examine the microstructure of large tracts of connections between brain regions.

If you are planning on getting this article and reading it, be warned....it is incredibly technical. That being said, let me give you a quick summary. The researchers observed that there were significant differences in three critical regions of the brain:

• The thalamus (the region for sensory inputs)
• The corpus callosum (which connects the two cortical hemispheres) 
• The cingulum which connects the cingulate cortex with another cortical region (the entorhinal cortex) that is is involved in the processing of memories.
• The major issue is that higher anisotropy was seen in these areas in men when compared to women. In layman's terms, the brain circuit's insulation in these regions are thicker which might indicated being more 'hardwired' or that these circuits are carrying a heavier neurological load. This is where interpretations can go in any number of directions.

One way to think of this, is to compare how the brain utilizes electical signals and compare it to how we use electricity in our homes. In the brain, each neuron receives a chemical signal called a neurotransmitter which causes that neuron to become electrically charged. If that neuron is sufficiently charged it will fire - this is called an action potential. The action potential is an electrical signal that is sent down the output part of the neuron (called an axon), so that it can release its neurotransmitters onto other neurons. In our homes, the electrical current that passes through the wires needs to be insulated so that it doesn't cause a fire or jump to a ground source. Needless to say, that is why the wires in our walls are insulated and covered in a continuous sheath of rubber. In the brain, however, the insulation is called myelin. It is this myelin that DTI is measuring - in essence it is looking at the thickness of the wiring in these brain regions.

It will be interesting to see how long it takes the media to get hold of this and how the research community responds to it.