Choline acetyltransferase-immunoreactive neurons in fetal monkey cerebral cortex.

Two monoclonal antibodies to choline acetyltransferase (ChAT) were used to stain the cerebral cortex of fetal monkeys at 110-150 days post-conception. In addition to a small number of immunostained fibers, cells resembling typical non-pyramidal neurons were immunostained in developing layers V and VI and in the subjacent white matter of each area examined (sensory-motor and visual areas). ChAT-immunoreactive neurons have not been described in the cerebral cortex of adult primates, but the present observations indicate such neurons exist in the developing primate cortex.