Acetylcholinesterase in the human frontal associative cortex during the period of cognitive development: early laminar shifts and late innervation of pyramidal neurons

Laminar preferences in fibrillar acetylcholinesterase (AChE) staining change dramatically in the human frontal cortex during the first postnatal year and perikaryal reactivity is found only in non-pyramidal neurons. The AChE reactivity of layer III pyramidal cell bodies and surrounding fibrillar network begins to develop after the first postnatal year, increases gradually and reaches its peak intensity in young adults, displaying a cluster-like arrangement. These data suggest that AChE-rich elements participate in the innervation of cortical associative neurons and layers during the cognitive development in man.