Lateralisation, Hubs and Cognition in the Mammalian and Avian Brain

Abstract

This article concerns an analysis of the frequently uttered statement that due to similarities in avian and mammalian brain connectivity and development comparable cognitive capacities are present. Two citations are given: "It is in the circuitry of mammalian and avian brains, rather than in their cytoarchitecture, that a marked degree of similarity exists"; "Cognitive functions are similar in birds and mammals". Subjects treated are physiognomy and phrenology, both exponents of form asymmetry, causing the awakening of functional asymmetry. Dax, Broca and their speech localisation in the human brain are dealt with. Lateralisation in mammals and birds, the importance of the corpus callosum, differences between cortex of mammals and pallium of birds are described. Claustrum's relation with cognition involves claustrum connections, split brain in humans is compared to avian hemisphere structure together with development of the avian and mammalian claustrum. Avian neuroanatomy contradicts the claim of similarity of mammalian and avian cognition.