Attentional amplification of neural codes for number independent of other quantities along the dorsal visual stream
Humans and other animals base important decisions on estimates of number, and intraparietal cortex is thought to provide a crucial substrate of this ability. However, it remains debated whether an independent neuronal processing mechanism underlies this 'number sense' or whether number is instead judged indirectly on the basis of other quantitative features. We performed high-resolution 7 Tesla fMRI while adult human volunteers attended either to the numerosity or an orthogonal dimension (average item size) of visual dot arrays. Along the dorsal visual stream, numerosity explained a significant amount of variance in activation patterns, above and beyond non-numerical dimensions. Its representation was selectively amplified and progressively enhanced across the hierarchy when task relevant. Our results reveal a sensory extraction mechanism yielding information on numerosity separable from other dimensions already at early visual stages and suggest that later regions along the dorsal stream are most important for explicit manipulation of numerical quantity.
Individual subjects' data points for behavioural and fMRI results for all regions of interest, corresponding to figure 2A, 3C, 5, 3-supplementary 1 and 2, 5-supplementary 1-2 are provided as .csv files. The maps displayed in figure 2B-D and 3B are provided in a format readable with Freesurfer/Freeview, one of the most widely used free neuroimaging softwares. The functional imaging dataset is available via the Open Science Framework (osf.io/6zch2).
Article and author information
Agence Nationale de la Recherche (ANR-14-CE13-0020-01)
- Evelyn Eger
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: The study was approved by the regional ethics committee (CPP Ile de France VII, Hôpital de Bicêtre, No. 15-007) and all participants gave written informed consent.
- Daniel Ansari
- Received: January 21, 2019
- Accepted: July 18, 2019
- Accepted Manuscript published: July 24, 2019 (version 1)
- Version of Record published: August 14, 2019 (version 2)
- Version of Record updated: October 16, 2019 (version 3)
© 2019, Castaldi et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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