Ancient visual channels have a causal role in arithmetic calculations

Abstract

Humans exhibit complex arithmetic skills, often attributed to our exceptionally large neocortex. However, the past decade has provided ample evidence that the functional domain of the subcortex extends well beyond basic functions. Using a sensitive behavioral method, for the first time, we explored the contributions of lower-order visual monocular channels to symbolic arithmetic operations, addition and subtraction. The pattern of results from 4 different experiments provides converging evidence for a causal relation between mental arithmetic and primitive subcortical regions. The results have major implications for our understanding of the neuroevolutionary development of general numerical abilities–subcortical regions, which are shared across different species, are essential to complex numerical operations. In a bigger conceptual framework, these findings and others call for a shift from the modal view of the exclusive role of the neocortex in high-level cognition to a view that emphasizes the interplay between subcortical and cortical brain networks.

Contributions of Lower Structures to Higher Cognition: Towards a Dynamic Network Model

“…By comparing performance between conditions solely dependent on monocular processing channels and conditions in which the information is integrated between the two eyes, one can make inferences about the kinds of visual computations that can be performed subcortically. This approach has been used to demonstrate the causal role of visual subcortical channels in attention, arithmetic, and other cognitive processes (Collins et al 2017;Gabay and Behrmann 2014;Saban et al 2018aSaban et al , 2019Saban et al , 2021aSoloveichick et al 2021).…”

“…Whereas the SEED hypothesis focuses on how new cognitive abilities emerge over the course of evolution, it is important to recognize that ancient subcortical computations continue to be essential for higher cognition, the critical idea of the Dynamic Network Model. Indeed, researchers have found that the subcortex contributes to many higher cognitive functions in humans spanning attention, arithmetic, language, executive functions, and more ( Collins et al 2017 ; Conway 2020 ; Gabay and Behrmann 2014 ; Saban et al 2017 , 2018 , 2019 , 2021a , 2021b ; Soloveichick et al 2021 ; Ullman 2001 ; Walenski et al 2007 ). In addition, higher cognitive functions are exhibited by many different organisms, including species that do not possess developed cortical structures, such as insects, pigeons, and fish ( Agrillo et al 2010 ; Gross et al 2009 ; Güntürkün and Bugnyar 2016 ; Howard et al 2018 ; Kattner et al 2017 ; Portavella et al 2004 ; Saban et al 2017 ; Schlegel and Schuster 2008 ).…”

“…Implicit by “neglect” is the assumption that the subcortex is of secondary importance when considering higher-level cognition, such as attention and math abilities. While research from the past decade has provided evidence that subcortical regions are engaged in some cognitive tasks ( Janacsek et al 2022 ; Saban et al 2018c , 2021a ), it is still a question of how (vs. if) the subcortex contributes to the computations essential for higher cognitive processes, with a focus on endogenous attention and numerical cognition.…”

Feasibility and Efficacy of Online Neuropsychological Assessment

“…Neuropsychological tests of subcortical disorders often focus on the basal ganglia and cerebellum, with patients with Parkinson's disease (PD) serving as a model for basal ganglia dysfunction and patients with cerebellar ataxia (CA) serving as a model for cerebellar dysfunction [5,6]. The most prominent symptoms of PD and CA are motor, with distinct impairments associated with the two disorders.…”