Published online by Cambridge University Press: 12 April 2004
Two issues in synapsid brain evolution are discussed: the presumed structure and function of the brain of the Synapsida/Diapsida common ancestral, and the enlargement of dorsal telencephalon. Ecological niches possibly occupied by some Carboniferous tetrapods are considered in order to speculate about evolution of major telencephalic sectors. An alternative interpretation of isocortical origins, based on differences in Pax-6 expression, is suggested for discussion.