An interdisciplinary approach to brain evolution: A long due debate
Francisco Aboitiz a1, Daniver Morales a2andJuan Montiel a1 a1 Departamento de Psiquiatría and Centro de Investigaciones Médicas, Facultad de Medicina, Pontificia Universidad Católica de Chile; and Millennium Nucleus for Integrative Neuroscience, Marcoleta 387, 2° piso, Casilla 114-D, Santiago 1, Chile
[email protected][email protected] a2 Developmental Neurobiology Laboratory, The Rockefeller University, New York, NY 10021
A dorsalization mechanism is a good candidate for the evolutionary origin of the isocortex, producing a radial and tangential expansion of the dorsal pallium (and perhaps other structures that acquired a cortical phenotype). Evidence suggests that a large part of the dorsal ventricular ridge (DVR) of reptiles and birds derives from the embryonic ventral pallium, whereas the isocortex possibly derives mostly from the dorsal pallium. In early mammals, the development of olfactory-hippocampal associative networks may have been pivotal in facilitating the selection of a larger and more complex dorsal pallium which received both collothalamic and lemnothalamic sensory information. Finally, although it is not clear exactly when mammalian brain expansion began, fossil evidence indicates that this was a late event in mammaliaform evolution.