Figure 1. A prosed thalamus-cortex (ACC) network for
consciousness
The direct projection from the thalamus to ACC serves as a key (if not
the only one) core circuits for consciousness. The projection to PFC
directly or indirectly may also contribute to this core. In addition,
different subnuclei of thalamus project to somatosensory, visual and
auditory cortices to convey sensory information from the outside world.
Pyramidal cells in these cortical areas form connections with ACC/PFC
neurons directly and indirectly. Through callosal projections, each side
of ACC may also affect other side of ACC by excitatory connections,
these positive feedback circuits provide a dual circuits for maintain
consciousness. Furthermore, in case of one side of brain injury, the
other side of circuits may take over to maintain minimal level of
consciousness. In addition, the pyramidal cells of ACC may also project
to subcortical and spinal cord neurons. These long distance positive
feedback circuits may also contribute to the consciousness.