 After development, reelin is secreted in the cortex and hippocampus by gamma-aminobutyric acid-ergic interneurons.Through binding of ApoER2 in the hippocampus, it plays a role in the NMDA receptor activation that is required for long-term potentiation, a mechanism by which two neurons gain a stronger, longer-lasting transmission due to simultaneous firing.The increased synaptic plasticity associated with this process is essential in development of memory and spatial learning.