Time And Science - Volume 2: Life Sciences

Book excerpt: Life and Time are very closely linked, because life needs the patience of eons to emerge and evolve, and also due to the precision timing of neural networks in the perception of the world, encoding information, and performing actions. A dozen renowned biologists and neuroscientists collaborate in this volume to explore the various facets of timing in the living world. The temporal programming of the activity of the genetic code controls the essential mechanisms of individual development from zygote to adult, while evolution uses the succession of generations to accomplish its work. For its part, the brain accomplishes the miracle of justifying presentism and reconstructing the continuity of present time from the fragmented data accessible to the senses, as well as measuring durations and dating events. To this end, the brain uses a multilevel temporal coding to transport and decode sensory information and prepare motor responses. It is only gradually that we have discovered the temporal precision of the mechanisms involved, of the order of a few milliseconds or less, for the adjustment of neural networks, or the synaptic plasticity used for memory formation. Today, the perfection of natural neural networks, the energy saving use of spikes of electrical impulses to categorize the sensory environment and to guess its probable future is an example to the modelers and engineers of artificial intelligence.