Neuronal code for number in the brains of humans, monkeys and crows

Summary

Date: 
March 5, 2019 - 12:00pm
Location: 
BioLabs Building, Room 1080
About the Speaker
Name: 
Andreas Nieder
Speaker Title: 
Professor
Speaker Affiliation: 
University of Tübingen

Judging the quantity of items in a set is an abstract form of categorization that provides a survival advantage to animals and constituted the basis for mathematics in humans. Findings in developmental psychology, anthropology, and animal cognition indicate that numerical skills are rooted in non-verbal biological primitives. To decipher the neuronal foundations of number representations from a comparative and evolutionary point of view, we studied single-cell activity in the association cortices of behaving human patients, monkeys and crows. Our data show an impressive correspondence of neuronal mechanisms in the brains of these diverse species: Neurons are tuned to individual preferred numerosities, and neuronal discharges prove to be relevant for both species’ correct performance. Both the neuronal and the behavioral tuning functions in primates and corvids are best described on a logarithmic number line, arguing for a non-linearly compressed coding of numerical information, just as predicted by the psychophysical Weber-Fecher Law. Our data suggest that this way of coding numerical information – which seems to constitute a superior solution to a common computational problem - has evolved at least twice based on convergent evolution, and irrespective of the precise origin and anatomical structures of vertebrate brains.