Neural Tuning to Numerosity Relates to Perceptual Tuning in 3–6-Year-Old Children

Abstract

Neural representations of approximate numerical value, or numerosity, have been observed in the intraparietal sulcus (IPS) in monkeys and humans, including children. Using functional magnetic resonance imaging, we show that children as young as 3-4 years old exhibit neural tuning to cardinal numerosities in the IPS and that their neural responses are accounted for by a model of numerosity coding that has been used to explain neural responses in the adult IPS. We also found that the sensitivity of children's neural tuning to number in the right IPS was comparable to their numerical discrimination sensitivity observed behaviorally, outside of the scanner. Children's neural tuning curves in the right IPS were significantly sharper than in the left IPS, indicating that numerical representations are more precise and mature more rapidly in the right hemisphere than in the left. Further, we show that children's perceptual sensitivity to numerosity can be predicted by the development of their neural sensitivity to numerosity. This research provides novel evidence of developmental continuity in the neural code underlying numerical representation and demonstrates that children's neural sensitivity to numerosity is related to their cognitive development.

Mechanisms of interactive specialization and emergence of functional brain circuits supporting cognitive development in children

“…Longitudinal changes in IPS connectivity supporting arithmetic problem solving The IPS has been shown to play a key role in quantity processing, and the development of both basic numeracy 17,44 as well as complex numerical problem solving skills. 37 In order to test the prediction that IPS connectivity changes over the course of Black circles represent single fMRI scan acquisitions, and multiple scans for one child are represented by interconnecting lines development, we computed IPS functional connectivity maps derived from the arithmetic verification task relative to a number identification control task.…”

How Evolution Constrains Human Numerical Concepts

“…(A) Neurons in intraparietal cortex respond maximally to a preferred numerical value and their firing rate decreases as a function of the numerical ratio of a stimulus to the preferred value (scale inverted to show parallels to human data in B; ). (B) Neural activity in intraparietal cortex in 3‐ to 6‐year‐olds is modulated by the numerical ratio between a standard stimulus and a novel stimulus .…”

“…A second prediction of evolutionarily primitive mechanisms is that they should emerge early in development . In a recent study, 3‐ to 6‐year‐old children were tested in an fMRI adaptation paradigm in which they saw a constant sequence of dot arrays that typically had the same numerical value, shape, surface area, and dot color ; the number, surface area, or dot color of the elements would change occasionally. The intraparietal sulcus responded more strongly to numerical changes than to other types of stimulus changes, even in 3‐ to 4‐year‐olds.…”

Neural basis of approximate number system develops independent of visual experience

“…A key open question concerns the developmental origins and role of experience in the establishment of IPS quantity representations. IPS responses to approximate number are present in children by the age of 3 to 4 years (Cantlon, Brannon, Carter, & Pelphrey, 2006;Kersey & Cantlon, 2017), and parietal responses to numerosities are revealed by near-infrared spectroscopy in 6-month old infants (Hyde, Boas, Blair, & Carey, 2010) and event-related potentials in 3-month old infants (Izard, Dehaene-Lambertz, & Dehaene, 2008). However, it is unclear whether and what kind of experience is necessary for this specialization.…”

“…Once in place, IPS number representations could become accessible through other sensory modalities and, in numerate humans, through symbols such as Arabic numerals. Neuroimaging findings in children do not address this possibility, as they have focused on visual stimuli Izard et al, 2008;Kersey & Cantlon, 2017).…”