The "Inferior Temporal Numeral Area" distinguishes numerals from other character categories during passive viewing: A representational similarity analysis

Authors

Darren J. Yeo, Department of Psychology & Human Development, Peabody College, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203, USA; Division of Psychology, School of Social Sciences, Nanyang Technological University, 48 Nanyang Avenue, 639818, Singapore.
Courtney Pollack, Lynch School of Education, Boston College, Campion Hall, 140 Commonwealth Ave, Chestnut Hill, MA, 02467, USA.
Rebecca Merkley, Brain and Mind Institute, and Department of Psychology, University of Western Ontario, Westminster Hall, London, ON, N6A 3K7, Canada; Institute of Cognitive Science, 2201 Dunton Tower, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
Daniel Ansari, Brain and Mind Institute, and Department of Psychology, University of Western Ontario, Westminster Hall, London, ON, N6A 3K7, Canada.Follow
Gavin R. Price, Department of Psychology & Human Development, Peabody College, Vanderbilt University, 230 Appleton Place, Nashville, TN, 37203, USA. Electronic address: gavin.price@vanderbilt.edu.

Document Type

Article

Publication Date

7-1-2020

Journal

NeuroImage

Volume

214

First Page

116716

URL with Digital Object Identifier

10.1016/j.neuroimage.2020.116716

Abstract

A region in the posterior inferior temporal gyrus (pITG) is thought to be specialized for processing Arabic numerals, but fMRI studies that compared passive viewing of numerals to other character types (e.g., letters and novel characters) have not found evidence of numeral preference in the pITG. However, recent studies showed that the engagement of the pITG is modulated by attention and task contexts, suggesting that passive viewing paradigms may be ill-suited for examining numeral specialization in the pITG. It is possible, however, that even if the strengths of responses to different category types are similar, the distributed response patterns (i.e., neural representations) in a candidate numeral-preferring pITG region ("pITG-numerals") may reveal categorical distinctions, even during passive viewing. Using representational similarity analyses with three datasets that share the same task paradigm and stimulus sets (total N = 88), we tested whether the neural representations of digits, letters, and novel characters in pITG-numerals were organized according to visual form and/or conceptual categories (e.g., familiar versus novel, numbers versus others). Small-scale frequentist and Bayesian meta-analyses of our dataset-specific findings revealed that the organization of neural representations in pITG-numerals is unlikely to be described by differences in abstract shape, but can be described by a categorical "digits versus letters" distinction, or even a "digits versus others" distinction (suggesting greater numeral sensitivity). Evidence of greater numeral sensitivity during passive viewing suggest that pITG-numerals is likely part of a neural pathway that has been developed for automatic processing of objects with potential numerical relevance. Given that numerals and letters do not differ categorically in terms of shape, categorical distinction in pITG-numerals during passive viewing must reflect ontogenetic differentiation of symbol set representations based on repeated usage of numbers and letters in differing task contexts.

Citation of this paper:

Darren J. Yeo, Courtney Pollack, Rebecca Merkley, Daniel Ansari, Gavin R. Price, The “Inferior Temporal Numeral Area” distinguishes numerals from other character categories during passive viewing: A representational similarity analysis, NeuroImage, Volume 214, 2020, 116716, ISSN 1053-8119, https://doi.org/10.1016/j.neuroimage.2020.116716. (https://www.sciencedirect.com/science/article/pii/S1053811920302032)