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Numerosity processing in early visual cortex.

Publication ,  Journal Article
Fornaciai, M; Brannon, EM; Woldorff, MG; Park, J
Published in: Neuroimage
August 15, 2017

While parietal cortex is thought to be critical for representing numerical magnitudes, we recently reported an event-related potential (ERP) study demonstrating selective neural sensitivity to numerosity over midline occipital sites very early in the time course, suggesting the involvement of early visual cortex in numerosity processing. However, which specific brain area underlies such early activation is not known. Here, we tested whether numerosity-sensitive neural signatures arise specifically from the initial stages of visual cortex, aiming to localize the generator of these signals by taking advantage of the distinctive folding pattern of early occipital cortices around the calcarine sulcus, which predicts an inversion of polarity of ERPs arising from these areas when stimuli are presented in the upper versus lower visual field. Dot arrays, including 8-32dots constructed systematically across various numerical and non-numerical visual attributes, were presented randomly in either the upper or lower visual hemifields. Our results show that neural responses at about 90ms post-stimulus were robustly sensitive to numerosity. Moreover, the peculiar pattern of polarity inversion of numerosity-sensitive activity at this stage suggested its generation primarily in V2 and V3. In contrast, numerosity-sensitive ERP activity at occipito-parietal channels later in the time course (210-230ms) did not show polarity inversion, indicating a subsequent processing stage in the dorsal stream. Overall, these results demonstrate that numerosity processing begins in one of the earliest stages of the cortical visual stream.

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Published In

Neuroimage

DOI

EISSN

1095-9572

Publication Date

August 15, 2017

Volume

157

Start / End Page

429 / 438

Location

United States

Related Subject Headings

  • Young Adult
  • Visual Fields
  • Visual Cortex
  • Pattern Recognition, Visual
  • Neurology & Neurosurgery
  • Mathematical Concepts
  • Male
  • Humans
  • Female
  • Evoked Potentials
 

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Fornaciai, M., Brannon, E. M., Woldorff, M. G., & Park, J. (2017). Numerosity processing in early visual cortex. Neuroimage, 157, 429–438. https://doi.org/10.1016/j.neuroimage.2017.05.069
Fornaciai, Michele, Elizabeth M. Brannon, Marty G. Woldorff, and Joonkoo Park. “Numerosity processing in early visual cortex.Neuroimage 157 (August 15, 2017): 429–38. https://doi.org/10.1016/j.neuroimage.2017.05.069.
Fornaciai M, Brannon EM, Woldorff MG, Park J. Numerosity processing in early visual cortex. Neuroimage. 2017 Aug 15;157:429–38.
Fornaciai, Michele, et al. “Numerosity processing in early visual cortex.Neuroimage, vol. 157, Aug. 2017, pp. 429–38. Pubmed, doi:10.1016/j.neuroimage.2017.05.069.
Fornaciai M, Brannon EM, Woldorff MG, Park J. Numerosity processing in early visual cortex. Neuroimage. 2017 Aug 15;157:429–438.
Journal cover image

Published In

Neuroimage

DOI

EISSN

1095-9572

Publication Date

August 15, 2017

Volume

157

Start / End Page

429 / 438

Location

United States

Related Subject Headings

  • Young Adult
  • Visual Fields
  • Visual Cortex
  • Pattern Recognition, Visual
  • Neurology & Neurosurgery
  • Mathematical Concepts
  • Male
  • Humans
  • Female
  • Evoked Potentials