During the past 20 years or so, biological sciences have advanced to the point that scientists have begun researching biological mechanisms of brain function and suggesting some reasonably well-founded hypotheses for consciousness. Leading the way in these pioneering efforts, in my judgment, have been:
Gerald Edelman with his hypothesis of the Dynamic Core,
Antonio Damasio with his concepts of Protoself, Core Self, Autobiographical Self, Core Consciousness and Extended Consciousness,
Joseph LeDoux and his emphasis on the intricacies of synapses and the emotional brain,