Brain complexity is reflected in the complexity of its structural makeup. The combinatorial possibilities are staggering for a nervous system with only 302 neurons. The authors suggest that it is important to recognize the differences between brains and computers.
Individual transistors are homogeneous and nonadaptive.
Alternatively, it is at this time equally plausible that consciousness arises out of a novel feature of certain types of brains, some cellular or circuit property with a unique molecular, anatomical, or physiological signature. Among important distinguishing characteristics of metazoa are cell differentiation and intercellular communication. Most ion channels are selective, allowing only certain ions to pass, and an individual cell has ion channels with various ion selectivities. Depending on the type of receptor, the result may be an excitatory or an inhibitory effect on the postsynaptic nerve cell. The G-protein is apparently embedded in the cell membrane with parts exposed on the outside surface and inside surface.