ORIGINAL RESEARCH published: 16 June 2016 doi: 10.3389/fnagi.2016.00136 Frontiers in Aging Neuroscience | www.frontiersin.org 1 June 2016 | Volume 8 | Article 136 Edited by: Lutz Jäncke, University of Zurich, Switzerland Reviewed by: Rongqiao He, Chinese Academy of Sciences, China Juliana Yordanova, Bulgarian Academy of Sciences, Bulgaria *Correspondence: Genevieve Z. Steiner G.Steiner@westernsydney.edu.au Received: 17 March 2016 Accepted: 27 May 2016 Published: 16 June 2016 Citation: Steiner GZ, Gonsalvez CJ, De Blasio FM and Barry RJ (2016) Electrophysiology of Memory-Updating Differs with Age. Front. Aging Neurosci. 8:136. doi: 10.3389/fnagi.2016.00136 Electrophysiology of Memory-Updating Differs with Age Genevieve Z. Steiner 1, 2 *, Craig J. Gonsalvez 3 , Frances M. De Blasio 2 and Robert J. Barry 2 1 The National Institute of Complementary Medicine (NICM), Western Sydney University, Penrith, NSW, Australia, 2 Centre for Psychophysics, Psychophysiology, and Psychopharmacology, Brain & Behaviour Research Institute, and School of Psychology, University of Wollongong, Wollongong, NSW, Australia, 3 School of Social Sciences and Psychology, Western Sydney University, Penrith, NSW, Australia In oddball tasks, the P3 component of the event-related potential systematically varies with the time between target stimuli—the target-to-target interval (TTI). Longer TTIs result in larger P3 amplitudes and shorter latencies, and this pattern of results has been linked with working memory-updating processes. Given that working memory and the P3 have both been shown to diminish with age, the current study aimed to determine whether the linear relationship between P3 and TTI is compromised in healthy aging by comparing TTI effects on P3 amplitudes and latencies, and reaction time (RT), in young and older adults. Older adults were found to have an overall reduction in P3 amplitudes, longer latencies, an anterior shift in topography, a trend toward slower RTs, and a flatter linear relationship between P3 and TTI than young adults. Results suggest that the ability to maintain templates in working memory required for stimulus categorization decreases with age, and that as a result, neural compensatory mechanisms are employed. Keywords: P3(00), aging, working memory, event-related potentials (ERPs), older adults, healthy aging, target-to- target interval (TTI), oddball task INTRODUCTION Electrophysiology of Memory-Updating Differs with Age Working memory, the ability to hold and manipulate information in the mind, decreases across the lifespan (Hedden and Gabrieli, 2004), particularly after 70 years of age (Hester et al., 2004). This age-related cognitive decline can result in a loss of confidence, independence, and reduced quality of life. The decline in working memory ability is thought to result from a reduction in regional brain volume and cortical thickness due to a loss of synaptic density, particularly in the prefrontal cortex (Kadota et al., 2001; Pieperhoff et al., 2008; Salat et al., 2009; Bishop et al., 2010). In order to devise strategies to mitigate the pathophysiology of the aging process, an increased understanding of age-related changes in brain function is required. The P3(00) component of the human event-related potential (ERP), a large positive deflection elicited by salient stimuli, has been described as an electrophysiological index of working memory processes (Squires et al., 1976, 1977; Polich, 1997). Previous work has shown that by extending the time between target stimuli (the target-to-target interval [TTI]), the P3 increases in amplitude and decreases in latency (Gonsalvez et al., 1999, 2007; Gonsalvez and Polich, 2002; Croft et al., 2003; Steiner et al., 2013a,b; Steiner et al., 2014a,b). This “TTI effect” on the P3 has been directly linked Abbreviations: EEG, Electroencephalogram; EOG, Electrooculogram; ERPs, Event-related potentials; MCI, Mild Cognitive Impairment; RT, Reaction time; TTI, Target-to-target interval.