Almost all sensorimotor and cognitive processes rely on the activity of large networks in the human brain, because in order to exchange and integrate information, different brain regions must dynamically couple with each other. The existence of such couplings was discovered more than 30 years ago, but it is still not clear exactly what their functional significance is. Results to date from model calculations, neuroscience imaging, and electrophysiology indicate that dynamic couplings of signals in the cortex have a key role in the emergence of perception, attention, memory performance, language, reasoning, and problem-solving abilities. From comparing data on the dynamics of neuronal signals in healthy and diseased brains, we have also found clues to the role that altered network dynamics play in diseases such as schizophrenia. During the processing of sensory impressions, many processes take place in parallel, i.e., humans or their brains are capable of multitasking and can, for example, clean up and listen to the radio at the same time. In everyday life, the process of multisensory integration is of great importance, enabling the exchange of information between the sensory systems involved in each case. The complex network dynamics in the circuits of the cerebral cortex are crucial for human cognitive abilities, such as perception, attention, memory performance, language and intelligence. Currently, network communication, which takes place on different spatial and temporal scales, is being intensively researched.