The number of neurons and their relative abundance in different parts of the brain is a determinant of neural function and, consequently, of behavior. Neurons may be packed to form structures such as the brain of vertebrates or the neural ganglions of insects. Not all animals have neurons Trichoplax and sponges lack nerve cells altogether. Neurons are the cells that transmit information in an animal's nervous system so that it can sense stimuli from its environment and behave accordingly. Scientists are engaged in counting, quantification, in order to find answers to the question in the strategy of neuroscience and intelligence of 'self-knowledge': how the evolution of a set of components and parameters (~10 11 neurons, ~10 14 synapses) of a complex system could lead to the phenomenon of the appearance of intelligence in the biological species 'sapiens'. The human brain contains 86 billion neurons, with 16 billion neurons in the cerebral cortex. The second list shows the number of neurons in the structure that has been found to be representative of animal intelligence. The first list shows number of neurons in their entire nervous system, indicating their overall neural complexity. The following are two lists of animals ordered by the size of their nervous system.
Brief comparisons of number of whole brain neurons (top) and cerebral cortex neurons (bottom) among six mammals.