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This clip shows the significant differences between Andrew and his 16-year-old son Cuinn in their ability to control impulses, and describes how brain maturation research can explain them. The early scenes show the two taking a counter-intuitive impulsiveness test as their brains are scanned by magnetic resonance imaging (MRI). The following scenes reveal Cuinn used twice as much brain area as his father to do much worse in the test. Using animations and comparing the MRI scans, researchers explain that the region controlling impulses is the last to mature.

Educational value points

• The process of 'sculpting’ or brain remodelling described in the clip involves little-used synapses being pruned away and those in use being strengthened and stabilised by white matter (myelin) wrapping itself around them. Research has shown that adolescence and early adulthood is a major period of brain development, as important as the early childhood years, with the sculpting processes usually beginning at about 12 years of age and ending at about 25.

• The sculpting process in the frontal lobe area of the brain begins at the back and moves forward, with a region known to be instrumental in controlling impulses among the last to mature. This region, called the dorsal lateral prefrontal cortex, does not reach its adult sculpted size until the mid-20s. The MRI scans show the cortex in Andrew’s brain is sculpted and so he easily controls impulses in the test. The cortex is not mature in Cuinn’s brain and so he fails.

• Brain research helps explain why adolescence and early adulthood can be times of over-confidence and high risk. Just before puberty a marked over-production of synapses, with a substantial increase in grey matter, takes place in the frontal lobe area. This burst of synapses, still in mid-adolescence relatively unsculpted and unrestrained by the brain’s 'braking system’, explains Cuinn’s creativity, belief that he is smarter than his father and failure in the test.

• As seen here, MRI and similar tools have transformed the field of neuroscientific research, allowing groundbreaking studies to be done on brain structure and function during adolescence. MRI uses radio waves generated in a strong magnetic field to detect small molecular changes in soft tissue such as the brain. Cross-sectional images and images in other planes are generated by computer from this information.

• Although the complexities of development in the brain’s four lobes are much simplified in this episode from the television science documentary series Catalyst, the clip shows the program’s ability to make exciting science accessible to the public. The father-and-son test provides a concrete visual example to act as an anchor for the explanation, while Cuinn’s modelling of his clay animation figure acts as a visual metaphor for the sculpting processes in his brain.

• Australian scientists are engaged in this field of research, with the Melbourne Neuropsychiatry Centre at the University of Melbourne where this footage was shot, building an international reputation for neuro-imaging and neuropsychological work on schizophrenia and psychosis. Professor Christos Pantelis is foundation professor of neuropsychiatry and scientific director and Dr Stephen Wood is a senior fellow with an interest in brain development during adolescence.