An important study of behavioral genetics looking at the effect of genes and environment (cannabis smoking) in the onset of the developmental condition, schizophrenia
Caspi, A., Moffitt, T. E., Cannon, M., McClay, J., Murray, R. M., Harrington, H. L., Taylor, A., Arseneault, L., Williams, B., Braithwaite, A., Poulton, R., & Craig, I. W. (2005). Moderation of the effect of adolescent onset cannabis use on adult psychosis by a functional polymorphism in the catechol-o-methyltransferase gene: Longitudinal evidence for a gene X–environment interaction. Biological Psychiatry, 57, 1117–1127.
A brain imaging study, conducted on adults, showing that the age at which a language is acquired affects the neural circuitry for syntax—even when level of expertise is matched
Wartenburger, I., Heekeren, H. R., Abutalebi, J., Cappa, S. F., Villringer, A., & Perani, D. (2003). Early setting of grammatical processing in the bilingual brain. Neuron, 37(1), 159–170.
A review paper discussing the possible neurobiological mechanisms underpinning sensitive periods in development
Thomas, M. S. C. & Johnson, M. H. (2008). New advances in understanding sensitive periods in brain development. Current Directions in Psychological Science, 17, 1–5.