On target selection as reflected by posterior ERP components in feature-guided visual search

Area of Science:

• Cognitive Neuroscience
• Psychology
• Neuroscience

Background:

• The N2pc event-related potential (ERP) reflects visuo-spatial attention to lateral targets.
• The N2pcb component was proposed for attention to midline targets, with two studies using different calculation algorithms.
• The singleton detection positivity (SDP) is a posterior positivity linked to N2pc in singleton search tasks.

Purpose of the Study:

• To validate two distinct algorithms for calculating the N2pcb component.
• To investigate the presence and characteristics of a posterior positivity component in feature search tasks.
• To propose a new name and baseline for this positivity component.

Main Methods:

• Comparison of two algorithms for N2pcb amplitude calculation in visual attention tasks.
• Electrophysiological recording and analysis of ERPs in response to lateral and midline targets.
• Exploration of a posterior bilateral positivity component in a feature search paradigm.

Main Results:

• Both algorithms accurately estimate N2pc and N2pcb components.
• A posterior bilateral positivity, termed posterior processing positivity (PPP), was identified in feature search.
• Bilateral activity from target-absent displays serves as a suitable baseline for isolating PPP.

Conclusions:

• The N2pcb component can be reliably measured using either of the two validated algorithms.
• The posterior processing positivity (PPP) is a distinct ERP component observable in feature-based attention tasks.
• Target-absent displays provide an effective baseline for isolating the PPP component in ERP research.