Spatio-temporal indications of sub-cortical involvement in leftward bias of spatial attention

Hadas Okon-Singer, Ilana Podlipsky, Tali Siman-Tov, Eti Ben-Simon, Andrey Zhdanov, Miri Y. Neufeld, Talma Hendler*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

A leftward bias is well known in humans and animals, and commonly related to the right hemisphere dominance for spatial attention. Our previous fMRI study suggested that this bias is mediated by faster conduction from the right to left parietal cortices, than the reverse (Siman-Tov et al., 2007). However, the limited temporal resolution of fMRI and evidence on the critical involvement of sub-cortical regions in orienting of spatial attention suggested further investigation of the leftward bias using multi-scale measurement. In this simultaneous EEG-fMRI study, healthy participants were presented with face pictures in either the right or left visual fields while performing a central fixation task. Temporo-occipital event related potentials, time-locked to the stimulus onset, showed an association between faster conduction from the right to the left hemisphere and higher fMRI activation in the left pulvinar nucleus following left visual field stimulation. This combined-modal finding provides original evidence of the involvement of sub-cortical central attention-related regions in the leftward bias. This assertion was further strengthened by a DCM analysis designated at cortical (i.e., inferior parietal sulcus; IPS) and sub-cortical (pulvinar nucleus) attention-related nodes that revealed: 1. Stronger inter-hemispheric connections from the right to left than vice versa, already at the pulvinar level. 2. Stronger connections within the right than the left hemisphere, from the pulvinar to the IPS. This multi-level neural superiority can guide future efforts in alleviating attention deficits by focusing on improving network connectivity.

Original languageEnglish
Pages (from-to)3010-3020
Number of pages11
JournalNeuroImage
Volume54
Issue number4
DOIs
StatePublished - 14 Feb 2011

Funding

FundersFunder number
HOS
Israel Science Foundation Converging Technologies Program
National Institute for Psychobiology in Israel
Tel Aviv University

    Keywords

    • Cross-correlation
    • Dynamic causal modeling (DCM)
    • Inferior parietal sulcus
    • Inter-hemispheric transfer time
    • Pulvinar
    • Simultaneous ERP-fMRI

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