Epistemological evaluation of evidence for 'number' neurons in the parietal cortex of macaque monkeys

A contemporary theory holds that mathematical concepts are stored in the long-term memory of mathematicians. This perspective also proposes that the brain has evolved to possess basic "representations" of space, time, and number. These representations are believed to be shared with other animal species and underlie mathematical intuition. To investigate this idea, neuronal recording studies were conducted in monkeys to search for an evolutionary precursor of the human ability to extract and manipulate numerical quantities. A sensitivity to the number of items was reported in the activity of some neurons in the parietal region of cerebral cortex. Area VIP contains neurons whose emission of action potentials is maximum for a specific number of items in the visual field, whereas area LIP contains two classes of cells, 'accumulator' neurons whose firing rate increases with the number of items, and other neurons whose activity decreases with the number of items. In this article, after questioning the reasons that have led to imagining that counting could be biologically inherited rather than culturally transmitted, we shall reveal the shortcomings of these studies conducted with monkeys, and report results that challenge an involvement of their parietal cortex in numerical competence.