A cortex-like canonical circuit in the avian forebrain

• Published in: Science (American Association for the Advancement of Science) 2020-09, Vol.369 (6511)
• Main Authors: Stacho, Martin, Herold, Christina, Rook, Noemi, Wagner, Hermann, Axer, Markus, Amunts, Katrin, Güntürkün, Onur
• Format: Article
• Language: English
• Subjects: Acuity; Aged, 80 and over; Animals; Architecture; Auditory pathways; Biological Evolution; Birds; Brain; Cerebral cortex; Chlorocebus aethiops; Cognition; Cognition & reasoning; Cognitive ability; Columbidae - anatomy & histology; Computational neuroscience; Depth Perception; Digital video recorders; Female; Forebrain; Homology; Humans; Hyperstriatum; Information processing; Iterative methods; Male; Mammals; Neocortex; Neocortex - ultrastructure; Neural networks; Neural Pathways - ultrastructure; Neuroimaging; Pallium; Pigeons; Polarized light; Prosencephalon - ultrastructure; Rats; Sensory integration; Skills; Somatosensory cortex; Strigiformes - anatomy & histology; Thinking Skills; Tracers; Tyto alba; Visual acuity; Visual pathways
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abc5534

Although the avian pallium seems to lack an organization akin to that of the cerebral cortex, birds exhibit extraordinary cognitive skills that are comparable to those of mammals. We analyzed the fiber architecture of the avian pallium with three-dimensional polarized light imaging and subsequently reconstructed local and associative pallial circuits with tracing techniques. We discovered an iteratively repeated, column-like neuronal circuitry across the layer-like nuclear boundaries of the hyperpallium and the sensory dorsal ventricular ridge. These circuits are connected to neighboring columns and, via tangential layer-like connections, to higher associative and motor areas. Our findings indicate that this avian canonical circuitry is similar to its mammalian counterpart and might constitute the structural basis of neuronal computation.