Spatial attention facilitates object working memory:An ERP study

Abstract

Objective To investigate the impact of attention on location,object and location-object working memory. Methods Event-related potentials (ERP) were recorded from 16 healthy subjects while performing tasks of the color-only,the location-only and the color-location binding memory separately. A repeated-measures factorial design was adopted with three levels (tasks:the color,the location,the binding). Results Significant differences of working memory capacity were found among tasks [F(1.95,29.23)=52.72,P =0.00] and listed in a decreasing order as:the location (3.258±0.610),the binding (2.300±0.735) and the color (1.298±0.520). Spatiotemporal patterns of the statistical parametric mapping (SPM) of F-value showed the task effect occurred during two stages:the consolidation stage (400'550 ms) in the frontal-central-parietal network and the maintenance stage (700'1100 ms) in bilateral ventral frontal-parietal regions. Spatiotemporal patterns of SPM(t) showed the significant differences between the color and the binding located at posterior parietal cortex during maintenance stage. Conclusion Spatial attention probably facilitates object working memory during both the consolidation stage by selective encoding and the maintenance stage by attention-based rehearsal mechanism. Key words: Working memory capacity; Spatial attention; Event-related potential (ERP); Statistical parametric mapping (SPM)