Neuroimaging and neurodevelopment

Question 1

Diffusion tensor imaging

Answer 1

• a technique used to study the integrity of white matter tracts
• shows that in children, with advancing age, the directionality of diffusion in white matter pathways continues to increase especially in the prefrontal regions and in the basal ganglia
• suggests frontostriatal systems myelinate progressively during adolescence
• DTI studies also show that the frontotemporal pathways may continue to myelinate until age of 30

Question 2

Magnetic resonance spectroscopy

Answer 2

• measures N-acetyl-aspartate
• indicator of neuronal integrity
• reveals low levels around birth that increase rapidly during the first 2 years of life
• this then slows down and may represent synaptogenesis during childhood

Question 3

Functional MRI

Answer 3

-studies reveal age-related increases in activation left frontal and temporal cortices (language areas) supporting the expansion of reading and phonological skills during childhood

Question 4

White matter volume

Answer 4

-increases linearly up to the age of 20 years in all brain regions

Question 5

Gray matter volumes

Answer 5

-frontal, parietal and temporal gray matter volumes follow an ‘inverted U-shaped’ developmental curve (increase before adolescence, frontoparietal peak at 12 years and temporal peak at 16 years of age, followed by a universal reduction thereafter

Question 6

Cortical thickness

Answer 6

-decreases with advancing age in ‘back to front’ progression starting from sensorimotor areas, progressing to the dorsal parietal, superior temporal. and dorsolateral pre-frontal cortices later