The influence of prenatal and pubertal testosterone on brain lateralisation

Several studies have examined the role of sex hormones on sexual differentiation of the brain. We investigate the influence of prenatal and pubertal testosterone on the development of brain lateralisation. Brain lateralisation... [ view full abstract ]

Several studies have examined the role of sex hormones on sexual differentiation of the brain. We investigate the influence of prenatal and pubertal testosterone on the development of brain lateralisation. Brain lateralisation is the functional specialization of the brain, with some functions accommodated more by the left hemisphere, and others by the right hemisphere. Lateralisation differs in strength and direction between individuals. The development of brain lateralisation is still elusive, but prenatal testosterone has been put forward as major factor influencing lateralisation. It is as yet unknown if pubertal testosterone also influences lateralisation.

There is long standing debate to what extent individual differences in lateralisation are due to variation in early or late exposure to testosterone. We use a unique data set to test this: [ view full abstract ]

There is long standing debate to what extent individual differences in lateralisation are due to variation in early or late exposure to testosterone. We use a unique data set to test this:

In the year 2000, prenatal testosterone levels were measured in the amniotic fluid of pregnant women. In the year 2015, brain lateralisation and cognitive performance is assessed in the children born from these pregnancies (30... [ view full abstract ]

In the year 2000, prenatal testosterone levels were measured in the amniotic fluid of pregnant women. In the year 2015, brain lateralisation and cognitive performance is assessed in the children born from these pregnancies (30 boys, 30 girls), and saliva samples are taken to measure pubertal testosterone levels.

Brain lateralisation of verbal fluency, mental rotation and facial emotion processing is measured with functional transcranial Doppler sonography (fTCD). Tanner's stage is assessed via an online questionnaire. [ view full abstract ]

Brain lateralisation of verbal fluency, mental rotation and facial emotion processing is measured with functional transcranial Doppler sonography (fTCD). Tanner's stage is assessed via an online questionnaire.

When only prenatal testosterone levels were included in the analysis, no effects on brain lateralisation were found. However, when both prenatal and pubertal testosterone levels were included in the analysis, we find... [ view full abstract ]

When only prenatal testosterone levels were included in the analysis, no effects on brain lateralisation were found. However, when both prenatal and pubertal testosterone levels were included in the analysis, we find interesting effects for boys. There is a significant interaction-effect for the mental rotation task and the chimeric faces task: in boys with low prenatal testosterone levels, pubertal testosterone strengthens brain lateralisation, while in boys with high prenatal testosterone levels, pubertal testosterone weakens brain lateralisation. In addition, mental rotation is significantly stronger lateralized in the right hemisphere in boys than in girls. For the word generation task there is no significant interaction effect, but there is a significant negative relation between pubertal testosterone and the lateralisation index: higher pubertal testosterone levels are related weaker lateralisation.

It is important to take both prenatal and pubertal testosterone into account. The effect of testosterone on brain lateralisation is task-dependent. [ view full abstract ]

It is important to take both prenatal and pubertal testosterone into account. The effect of testosterone on brain lateralisation is task-dependent.