Foetal testosterone effects on brain development. (360G-Wellcome-091774_Z_10_Z)

In this application we test if foetal testosterone (fT) (produced at significantly higher levels in males) exerts organisational effects on human brain development. Whilst fT has been demonstrated to exert organisational effects on brain development in other animals, this hypothesis has never been directly tested in humans. We have conducted a unique study where we measured fT prenatally in amniotic fluid and followed the children from birth to predict behavioural development longitudinally. Our research thus far has shown that fT is a key predictor of various social and communicative behaviours. We now have a valuable opportunity to employ neuroimaging with this sample to examine the underlying effects of fT on brain development. Our primary aims are: (1) To test if foetal testosterone (fT) and/or current testosterone (cT) correlate with volume of the whole brain and/or with volume of specific sexually-dimorphic brain regions, using structural MRI. (2) To test if fT and/or cT co rrelate with brain activity in these sexually-dimorphic brain regions, during social-emotional processing using functional MRI. (3) To test if fT and/or cT correlate with measures of neuroanatomical connectivity using diffusion tensor imaging (DTI).