  A sampling of recent neural theories might include models that appeal to global integrated fields (Kinsbourne), binding through synchronous oscillation (Singer 1999, Crick and Koch 1990), NMDA-mediated transient neural assemblies (Flohr 1995), thalamically modulated patterns of cortical activation (Llinas 2001), reentrant cortical loops (Edelman 1989), comparator mechanisms that engage in continuous action-prediction-assessment loops between frontal and midbrain areas (Gray 1995), left hemisphere based interpretative processes (Gazzaniga 1988), and emotive somatosensory hemostatic processes based in the frontal-limbic nexus (Damasio 1999) or in the periaqueductal gray (Panksepp 1998).