Independent from each other, birds and mammals have developed similar brain organizations that could constitute the neural basis of their cognitive skills. Birds have a functional analog to the prefrontal cortex that generates executive functions. Their telencephalic connectome is highly similar to that of diverse mammalian species and they show a ‘hidden’ lamination that resembles cortical canonical circuits in parts of their sensory pallial territories.

Birds lack a neocortex but have instead several large pallial aggregations without apparent laminar structure. However, according to some scientists, these aggregations might correspond to cortical layers.

The cerebrum of birds and mammals is homologous but very differently organized.

Cognition in corvids and parrots reaches the same level of excellence and diversity as in apes. Among others, bird cognition encompasses abilities such as delay of gratification, mental time travel, reasoning, metacognition, mirror self-recognition, theory of mind, and third-party intervention.

Assumptions on the neural basis of cognition usually focus on cortical mechanisms. Birds have no cortex, but recent studies in parrots and corvids show that their cognitive skills are on par with primates. These cognitive findings are accompanied by neurobiological discoveries that reveal avian and mammalian forebrains are homologous, and show similarities in connectivity and function down to the cellular level. But because birds have a large pallium, but no cortex, a specific cortical architecture cannot be a requirement for advanced cognitive skills. During the long parallel evolution of mammals and birds, several neural mechanisms for cognition and complex behaviors may have converged despite an overall forebrain organization that is otherwise vastly different.

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You are who you talk with – a commentary on Dugas-Ford et al. Proc. Natl. Acad. Sci. U.S.A.

Selective early expression of the orphan nuclear receptor Nr4a2 identifies the claustrum homologue in the avian mesopallium: impact on sauropsidian/mammalian pallium comparisons.

Pallial and subpallial derivatives in the embryonic chick and mouse telencephalon, traced by the expression of the genes Dlx-2, Emx-1, Nkx-2.1, Pax-6, and Tbr-1.

What birds with complex social relationships can tell us about vocal learning: vocal sharing in avian groups.

A capuchin monkey Cebus apella recognizes when people do and do not know the location of food.

Does the chimpanzee have a theory of mind? 30 years later.

Mirror-mark tests performed on jackdaws reveal potential methodological problems in the use of stickers in avian mark test studies.

Do apes know that they could be wrong?.

With his memory magnetically erased, a monkey knows he is uncertain.

Cognitive mechanisms for transitive inference performance in rhesus monkeys: measuring the influence of associative strength and inferred order.

Inferences about the location of food in capuchin monkeys Cebus apella in two sensory modalities.

What you see is what you get – reloaded: can jackdaws Corvus monedula find hidden food through exclusion?.

Chimpanzees fail to plan in an exchange task but succeed in a tool-using procedure.

Eurasian jays Garrulus glandarius overcome their current desires to anticipate two distinct future needs and plan for them appropriately.

Can animals recall the past and plan for the future?.

Waiting for better, not for more: corvids respond to quality in two delay maintenance tasks.

Behavioral responses to inequity in reward distribution and working effort in crows and ravens.

Ravens notice dominance reversals among conspecifics within and outside their social group.

Neurons selective to the number of visual items in the corvid songbird endbrain.

Anatomical organization of the visual dorsal ventricular ridge in the chick Gallus gallus: layers and columns in the avian pallium.

From sauropsids to mammals and back: new approaches to comparative cortical development.

Global view of the functional molecular organization of the avian cerebrum: mirror images and functional columns.

Single units in the pigeon brain integrate reward amount and time-to-reward in an impulsive choice task.

Neurons in the pigeon nidopallium caudolaterale signal the selection and execution of perceptual decisions.

Differential increase of extracellular dopamine and serotonin in the ‘prefrontal cortex’ and striatum of pigeons during working memory.

Microdialysis in the ‘prefrontal cortex’ and the striatum of pigeons Columba livia: evidence for dopaminergic volume transmission in the avian associative forebrain.

The receptor architecture of the pigeons’ nidopallium caudolaterale – an avian analogue to the prefrontal cortex.

Afferent and efferent connections of the caudolateral neostriatum in the pigeon Columba livia: a retro- and anterograde pathway tracing study.

Evolution of the amniote pallium and the origins of mammalian neocortex.

The organization of the avian telencephalon and some speculations on the phylogeny of the amniote telencephalon.

Using the Aesop's fable paradigm to investigate causal understanding of water displacement by New Caledonian crows.

What you see is what you get? Exclusion performances in ravens and keas.

Observational learning and the raiding of food caches in ravens, Corvus corax: is it ‘tactical’ deception?.

Food-caching scrub-jays keep track of who was watching when.

On the lack of evidence that non-human animals possess anything remotely resembling a ‘theory of mind’.

The mentality of crows: convergent evolution of intelligence in corvids and apes.

The dopaminergic innervation of the pigeon caudolateral forebrain: immunocytochemical evidence for a ‘prefrontal cortex’ in birds?.

The avian subpallium: new insights into structural and functional subdivisions occupying the lateral subpallial wall and their embryological origins.

Glossary

those parts of the brain that contain the pallial and subpallial territories. In mammals this incorporates the cortex, the hippocampus, the claustrum, the amygdala, the basal ganglia, and the olfactory bulb.

refers to the independent evolution of similar characters in species of different lineages due to comparable selection pressures. Convergent evolution results in analogous characters with similar appearances or functions, although these were not present in the last common ancestor of the two lineages.

birds of the crow family, a relatively closely related group of oscine passerine birds that includes crows, ravens, rooks, magpies, choughs, jays, and nutcrackers, and is found worldwide. Most species are characterized by a high brain-to-body mass ratio, ecological flexibility, and a complex social life, featuring long-term partnerships and dynamic groups structured by social relationships.

the study of pathways between brain areas. The term derives from the Greek word hodos which means ‘road’.

describes cases in which a shared trait of two species can be traced back to a common ancestor without interruption.

most of the neocortex has six cellular layers or laminae. Each layer is constituted by distinctive cell populations with unique connectivity patterns. At first glance, neocortical lamination looks uniform (and is therefore sometimes called ‘isocortical’). But a closer look reveals multitudes of subtle differences between neocortical areas.

the usually six-layered sheet of gray matter that constitutes the outermost part of the cerebrum of the mammalian brain.

refers to the upper surface of the cerebrum and incorporates cortex or cortex–homolog structures, hippocampus, pallial amygdala, claustrum, and olfactory bulb.

describes the evolution of a similar character starting from a comparable ancestral condition. Thus, during parallel evolution two taxa start by sharing a similar ancestral character and then subsequently develop independent from each other a further similar character from this ancestral condition.

are birds of the order Pscittaciformes that include ‘true’ parrots, cockatoos, and New Zealand parrots and are found in most tropical and subtropical regions. Similar to corvids, they are characterized by a high brain-to-body mass ratio and a complex social life, featuring long-term partnerships and dynamic groups structured by social relationships.

refers to the non-pallial part of the cerebrum and contains striatum, pallidum, striatal amygdala, and diagonal band of Broca.

the neocortical layer IV receives sensory information from primary thalamic relay nuclei and is therefore called the thalamorecipient lamina. Other thalamic nuclei that do not participate in rapid unimodal sensory transfer project to neocortical laminae I–II and V–VI. Thus, lamina IV can be called thalamorecipient only with regard to fast unimodal thalamic sensory input.