Figure 1.

Neurodevelopmental stages that contribute to the excitation/inhibition balance. During the development of the nervous systems, several processes lead to the correct formation and connection of neuronal circuits, achieving an excitation/inhibition balance. These processes are (a) Activity-dependent plasticity: neuronal activity induces formation of new synapses; (b) Synapse formation: synapses form through cell-cell recognition processes where neurexin and neuroligin form complexes; (c) Migration of neurons: the migration of neurons to the appropriate layers is necessary for the correct functioning of neuronal circuits. NRXN—Neurexin; NLGN—Neuroligin; CP—Cortical Plate; IZ—Intermediate Zone; VZ—Ventricular Zone.