||Tuning curves for approximate numerosity in the human intraparietal sulcus
Number, like color or movement, is a basic property of the environment. Recently, single neurons tuned to number have been observed in animals.We used both psychophysics and neuroimaging to examine whether a similar neural coding scheme is present in humans. When participants viewed sets of items with a variable number, the bilateral intraparietal sulci responded selectively to number change. Functionally, the shape of this response indicates that humans, like other animal species, encode approximate number on a compressed internal scale. Anatomically, the intraparietal site coding for number in humans is compatible with that observed inmacaquemonkeys. Our results therefore suggest an evolutionary basis for human elementary arithmetic.