The functional activity of the cerebral cortex depends on the number and type of neurons including synapses and transmitters. The wiring of the cerebral cortex is of high importance for its function. The prenatal development of this process is genetically controlled, but the environmental factors play an important role. The formed neural circuits and networks possess the ability of reorganization during the postnatal life formation of new synaptic contacts and elimination of some synapses. The epigenetic factor and social interactions produce changes on the synaptic level which play a role in learning capacity, memory and behaviour. The different areas in the lobes of cerebral cortex are responsible for a number of different functions motor and sensory functions, vision, auditory information, taste, olfaction, intellect, behaviour, emotions, creative thoughts, planning, language, recognition, orientation, and many others. The association areas take a large part of the cerebral cortex. The stimulation of brain by means of active verbal interaction with a child would develop the mental capacity. Abnormalities in cerebral cortex were established in schizophrenia, bipolar disorder and unipolar depression. It is possible to build better brain in an adult by means of daily mind gym. Mental and physical activity and intensive social contacts are necessary for the protection of the cerebral cortex in aged individuals. The brain plasticity, starting from the prenatal development till the end of life, must be taken into consideration.