There are additional daunting challenges to addressing questions of consciousness outside the vertebrate lineage, given the radical differences between vertebrates and invertebrates with respect to anatomy and physiology. The strategy of identifying homologous and functionally analogous structures and processes, which underlies the confidence of researchers such as Cabanac (2009), Seth et al. (2005), Merker (2005), and Panksepp (2005) that consciousness is shared with other animals is much more difficult to apply (Seth et al. 2005).