Neurons in vertebrate and invertebrate brains use characters that are unique to encode the things happening in the external world. The coding characters are the electrical signals to process all types of information, such as visual, auditory, taste, smell. The only electrical signal that neurons produce, transmit, recognize and use is action potential, with which for example, brain knows what a word means or how cold the weather is. The temporal characteristics of action potentials generated by neurons is important in coding different modules of information. In this review, an attempt for understanding the higher functions of the brain is made by correlating the temporal activity of individual nerve cells to the coding the information.