Towards a unified understanding of lateralized vision: A large-scale study investigating principles governing patterns of lateralization using a heterogeneous sample

Sanne G Brederoo,Lise Van Der Haegen,Marc Brysbaert,Mark R Nieuwenstein,Frans W Cornelissen,Monicque M Lorist

doi:10.1016/j.cortex.2020.08.029

Sanne G Brederoo, Lise Van Der Haegen + Show 4 more

Open Access

https://doi.org/10.1016/j.cortex.2020.08.029

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Journal: Cortex	Publication Date: Sep 29, 2020
Citations: 15	License type: cc-by

Affiliation: Ghent University, University of Groningen

Abstract

While functional lateralization of the human brain has been a widely studied topic in the past decades, few studies to date have gone further than investigating lateralization of single, isolated processes. With the present study, we aimed to arrive at a more unified view by investigating lateralization patterns in face and word processing, and associated lower-level visual processing. We tested a large and heterogeneous participant group, and used a number of tasks that had been shown to produce replicable indices of lateralized processing of visual information of different types and complexity. Following Bayesian statistics, group-level analyses showed the expected right hemisphere (RH) lateralization for face, global form, low spatial frequency processing, and spatial attention, and left hemisphere (LH) lateralization for visual word and local feature processing. Compared to right-handed individuals, lateralization patterns of left-handed and especially those who are RH-dominant for language deviated from this ‘typical’ pattern. Our results support the notion that face and word processes come to be lateralized to homologue areas of the two hemispheres, under influence of the RH- and LH-specializations in global form, local feature, and low and high spatial frequency processing. As such, we present a more unified understanding of lateralized vision, providing evidence for the input asymmetry and causal complementarity principles of lateralized visual information processing. The absence of correlations between spatial attention and lateralization of the other processes supports the notion of their independent lateralization, conform the statistical complementarity principle.

Highlights

Functional lateralization, or the differential specialization of the two cerebral hemispheres, enables the human brain to process a multitude of different types of information in an efficient and optimized manner (Hellige, 1993)
The results showed that the more LHlateralized the children were for word processing, the more RH-lateralized they were for face processing, as reflected by the differing magnitudes of the measured event-related potentials (ERPs) in response to word and face stimuli
The typical and deviating patterns of lateralization of face, word, global form, local feature, low and high spatial frequency processing can best be explained by the governing principles of input asymmetry and, to a lesser extent, causal complementarity

Summary

Introduction

Functional lateralization, or the differential specialization of the two cerebral hemispheres, enables the human brain to process a multitude of different types of information in an efficient and optimized manner (Hellige, 1993). Previous studies have suggested a number of hypotheses about the principles that may govern patterns of lateralization, which we here summarize as the statistical complementarity (Bryden, Hecaen, & DeAgostini, 1983), causal complementarity (Bryden et al, 1983), and input asymmetry (Andresen & Marsolek, 2005) principles. Each of these three principles assumes that various processes are lateralized, and attempt to explain patterns of lateralized processing

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