Consciousness is one of final questions for humans to tackle in
neuroscience. Due to the lack of understanding of the basic brain
network and mechanisms of functions, our knowledge of consciousness
remains at the theoretical level. Recent studies using brain imaging in
humans and modern neuroscience techniques in animal studies reveal a
basic brain network for consciousness. The projection from the thalamus
to different cortical regions form a network of activities to maintain
consciousness in human and animals. These feedback and feedforward
circuits maintain the consciousness even in certain brain injury
conditions. Proteins and ion channels that contribute to these circuit
neural activities are targets for drugs and manipulations that affect
consciousness, such as anesthetic agents. Synaptic plasticity that
trains synapses during learning and information recall, modify circuits
and contribute to a high level of consciousness in certain populations.