Published on December 19, 2018 | Updated on January 29, 2019

CORTEX conference by Rob van der Lubbe

June 26th, 2016

Lateralized power spectra of the EEG to index visuospatial and somatosensory spatial attention.

In 2013, Van der Lubbe and Utzerath proposed an extension of a lateralization index of the raw EEG introduced by Thut et al. (2006). The general idea of the method is to isolate relevant from irrelevant brain activity by taking advantage of the fact that many processes are lateralized. General hemispherical differences may confound a single contralateral minus ipsilateral subtraction while application of a double subtraction procedure circumvents this problem. The lateralized readiness potential (LRP) and the posterior contralateral negativity (PCN/N2pc) are based on the same principle, however, these measures are derived from event related potentials, which implies that activity that is not phase-locked to stimulus onset is cancelled out. By determining the lateralized power in various frequency bands it can be determined whether these frequencies depend on lateralized processes. Van der Lubbe and Utzerath (2013) determined the so-called lateralized power spectra (LPS) in an endogenous orienting paradigm, and observed increased ipsilateral vs. contralateral activity in the theta, alpha and beta bands. Van der Lubbe et al. (2014) used the same method to examine the overlap between external and internal spatial attention. Recent findings from several other unpublished studies will be presented. On the basis of their results it will be argued that the LPS method may be an important tool to investigate sensory and attentional processes, and also processes such as motor preparation and motor imagery.