I want to point to an excellent review by Christof Koch and colleagues. It contains some useful summary graphics.
•Empirical data suggest that consciousness is not necessary for integration.
•Unconscious integration is nevertheless limited.
•Consciousness enables integrations over extended spatiotemporal windows.
•Consciousness may be needed for novel and high-level semantic integrations.
Information integration and consciousness are closely related, if not interdependent. But, what exactly is the nature of their relation? Which forms of integration require consciousness? Here, we examine the recent experimental literature with respect to perceptual and cognitive integration of spatiotemporal, multisensory, semantic, and novel information. We suggest that, whereas some integrative processes can occur without awareness, their scope is limited to smaller integration windows, to simpler associations, or to ones that were previously acquired consciously. This challenges previous claims that consciousness of some content is necessary for its integration; yet it also suggests that consciousness holds an enabling role in establishing integrative mechanisms that can later operate unconsciously, and in allowing wider-range integration, over bigger semantic, spatiotemporal, and sensory integration windows.
