Number neurons in the nidopallium of young domestic chicks

Abstract

Numerical cognition is ubiquitous in the animal kingdom. Domestic chicks are a widely used developmental model for studying numerical cognition. Soon after hatching, chicks can perform sophisticated numerical tasks. Nevertheless, the neural basis of their numerical abilities has remained unknown. Here, we describe for the first time number neurons in the caudal nidopallium (functionally equivalent to the mammalian prefrontal cortex) of young domestic chicks. Number neurons that we found in young chicks showed remarkable similarities to those in the prefrontal cortex and caudal nidopallium of adult animals. Thus, our results suggest that numerosity perception based on the labeled-line code provided by number neurons might be an inborn feature of the vertebrate brain.

Magnitude shifts spatial attention from left to right in rhesus monkeys as in the human mental number line

“… 44 In birds, neurons selective to numerosities have been observed in the association area Nidopallium caudolaterale (NCL), a brain area possibly homologous with mammalian cortex, in both the crow 45 and the chick. 46 In humans, populations of neurons tuned to small numerosities are organized topographically in the parietal cortex, thereby forming a map, 47 , 48 which may underlie the spatial organization of magnitudes. Together, this evidence suggests that direction of attention along the mental number line and spatial numerical association may jointly arise from the neural mechanisms supporting the orienting of spatial attention.…”