AUTHOR=Shanahan Murray , Bingman Verner P., Shimizu Toru , Wild Martin , Güntürkün Onur TITLE=Large-scale network organization in the avian forebrain: a connectivity matrix and theoretical analysis JOURNAL=Frontiers in Computational Neuroscience VOLUME=7 YEAR=2013 URL=https://www.frontiersin.org/journals/computational-neuroscience/articles/10.3389/fncom.2013.00089 DOI=10.3389/fncom.2013.00089 ISSN=1662-5188 ABSTRACT=

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.