The peak periods of key neurodevelopmental events are depicted. Reference to timing of neurotransmitter system development includes appearance of receptors, transporters and synthetic machinery. Note that some of these neurotransmitter elements may continue to mature through puberty. Gestational age for both human (black font) and mouse (red font) are aligned with the black arrow to define the timeline for these events. Emerging drug targets (receptors, transporters, etc) are depicted along this same timeline in purple. Aff, afferents; CP, cortical plate; CTX, cortex; DA, dopamine; E, embryonic; GE, ganglionic eminence; LC, locus coeruleus; M, months; MZ, marginal zone; P, postnatal; PZ, proliferative zone; SP, sub-plate; VTA, ventral tegmental area; W, weeks; 5-HT, serotonin. Adapted from 202, 203.