Many species of birds, including pigeons, possess demonstrable cognitive capacities, and some are capable of cognitive feats matching those of apes. Since mammalian cortex is laminar while the avian telencephalon is nucleated, it is natural to ask whether the brains of these two cognitively capable taxa, despite their apparent anatomical dissimilarities, might exhibit common principles of organization on some level. Complementing recent investigations of macro-scale brain connectivity in mammals, including humans and macaques, we here present the first large-scale “wiring diagram” for the forebrain of a bird. Using graph theory, we show that the pigeon telencephalon is organized along similar lines to that of a mammal. Both are modular, small-world networks with a connective core of hub nodes that includes prefrontal-like and hippocampal structures. These hub nodes are, topologically speaking, the most central regions of the pigeon's brain, as well as being the most richly connected, implying a crucial role in information flow. Overall, our analysis suggests that indeed, despite the absence of cortical layers and close to 300 million years of separate evolution, the connectivity of the avian brain conforms to the same organizational principles as the mammalian brain.
Keywords: brain connectivity, avain neuroanatomy, brain network analysis, pigeon forebrain, comparative neuroanatomy
Citation: Shanahan M, Bingman VP, Shimizu T, Wild M and Güntürkün O (2013) Large-scale network organization in the avian forebrain: a connectivity matrix and theoretical analysis. Front. Comput. Neurosci. 7:89. doi: 10.3389/fncom.2013.00089
Received: 08 March 2013; Accepted: 17 June 2013;
Published online: 04 July 2013.
Edited by:Si Wu, Beijing Normal University, China
Reviewed by:Joaquín J. Torres, University of Granada, Spain;
Copyright © 2013 Shanahan, Bingman, Shimizu, Wild and Güntürkün. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Murray Shanahan, Department of Computing, Imperial College London, 180 Queen's Gate, London SW7 2RH, UK e-mail: firstname.lastname@example.org