Canine sense of quantity: Evidence for numerical ratio-dependent activation in parietotemporal cortex

• Type of Material: Article
• Authors: Lauren S. Aulet, Emory University; Veronica C. Chiu, Emory University; Ashley Prichard, Emory University; Mark Spivak, Comprehensive Pet Therapy, Atlanta; Stella Lourenco, Emory University; Gregory Berns, Emory University
• Language: English
• Date: 2019-12-01
• Publisher: The Royal Society Publishing
• Publication Version: Final Published Version
• Copyright Statement: © 2019 The Authors.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1098/rsbl.2019.0666
• Title of Journal or Parent Work: Biology Letters
• Volume: 15
• Issue: 12
• Start Page: 20190666
• End Page: 20190666
• Grant/Funding Information: This work was supported by a National Institutes of Health (NIH) institutional training grant (no. T32 HD071845) to L.S.A., a Scholar Award from the John Merck Fund to S.F.L. and a grant from the Office of Naval Research (grant no. N00014-16-1-2276) to G.S.B.
• Keywords: fMRI; Parietal Lobe; parietal cortex; Animals; Humans; Cerebral Cortex; Magnetic Resonance Imaging; approximate number system; canine cognition; Dogs; quantity discrimination
• Research Categories: Psychology, General; Biology, Animal Physiology; Biology, Neuroscience

Abstract

The approximate number system (ANS), which supports the rapid estimation of quantity, emerges early in human development and is widespread across species. Neural evidence from both human and non-human primates suggests the parietal cortex as a primary locus of numerical estimation, but it is unclear whether the numerical competencies observed across non-primate species are subserved by similar neural mechanisms. Moreover, because studies with non-human animals typically involve extensive training, little is known about the spontaneous numerical capacities of non-human animals. To address these questions, we examined the neural underpinnings of number perception using awake canine functional magnetic resonance imaging. Dogs passively viewed dot arrays that varied in ratio and, critically, received no task-relevant training or exposure prior to testing. We found evidence of ratio-dependent activation, which is a key feature of the ANS, in canine parietotemporal cortex in the majority of dogs tested. This finding is suggestive of a neural mechanism for quantity perception that has been conserved across mammalian evolution.