Zaremba observed that the development of similar neural circuitry is more adaptable than expected, noting that identical circuits can arise from various cell types. Her team discovered that in the bird pallium, neurons originating from different regions during development can mature into the same neuron type in adulthood. This challenges the previous belief that distinct embryonic regions produce different neurons.
Maria Tosches from Columbia University commented on the limited degrees of freedom in generating an intelligent brain among vertebrates. In mammals, brain development follows a predictable pattern, with cells from specific embryonic regions ending up in their corresponding adult structures. However, according to Güntürkün, birds exhibit an unexpected reorganization of the forebrain.
The research provides strong evidence that birds and mammals separately evolved complex cognitive brain regions. It aligns with prior research from Tosches’ lab, suggesting the mammalian neocortex evolved independently from the reptilian DVR. Some genetic similarities indicate inheritance from a common ancestor. Kempynck and Hecker, using deep learning, found shared DNA sequences in mice, chickens, and humans that influence neocortex or DVR development, implying similar genetic mechanisms. Additionally, inhibitory neurons are conserved across birds and mammals.
The findings do not fully resolve the debate between Karten and Puelles. Tosches sided with Puelles, while Güntürkün leaned towards Karten’s ideas, and García-Moreno suggested both were correct.
Tosches stated that intelligence lacks a defined blueprint, emerging from various biological innovations and convergent evolution across species. Bradley Colquitt from UC Santa Cruz noted the studies highlight multiple neural solutions to adaptation challenges. Examples of independent evolution include octopuses and squids developing camera-like eyes, and different species achieving flight.
Outside vertebrates, intelligent brains evolve distinctly, as seen in octopuses. Understanding how octopuses achieved intelligence could identify constraints on its evolution. Zaremba indicated such research might reveal shared features of intelligence and aid in searching for extraterrestrial intelligence and advancing artificial intelligence. Kempynck expressed interest in exploring AI from a bird’s perspective, questioning how their cognitive processes can be mimicked.
