When does individual human life (personhood) begin? Brain cortex is necessary for the personhood but there exist two different types of cortex with two different stages of development. While neocortex does not begin to get organized before 24 weeks, allocortex is already formed at 13th week of development.
Allocortical structures such as hippocampal formation and amygdala are involved in the emotions and memory, and regarded as the seat of personhood. At 13th week, fetus has an adult type allocortex by functional and anatomic definition and it is the most reasonable time at which to fix the start of individual human life (personhood).
Most religious traditions hold that what makes one a person is the possession of a soul. Ensoulment seems to occur when allocortex is formed at 13th week of development. Allocortical birth theory suggests that abortion and embryo research are acceptable ethically up to the point of allocortex formation.
Allocortex; Amygdala; Development; Ethics; Hippocampal formation; Personhood