Serial Position Effects in Auditory Event-related Potentials during Working Memory Retrieval

Abstract

Abstract& It is established that recall of an item from a list of sequentially presented items is sensitive to the item's position in the memorized list. However, little is known about the brain mechanisms that mediate these serial position effects. Studies of working memory retrieval using event-related potentials report amplitude reductions during retrieval (auditory cortical N100, neocortical late positive wave [LPW]) as memory load increases. We tested the hypothesis that N100 and LPW amplitudes to probes are also affected by serial position. Eventrelated potentials were recorded from subjects performing an auditory working memory task. A set of one or five digits was memorized, then subjects classified a probe digit as either present or absent from the memory set. A control task was also given. Amplitudes of the N100 and LPW were reduced in the 5-item versus the 1-item set. In the 5-item set N100 amplitude was significantly larger for the initial (1st) serial position, relative to Positions 2-5, while linear increases in LPW amplitude were seen across serial positions (5th > 1st position). A control task without memorization showed no N100 or LPW amplitude changes with set size or serial position. The findings reveal that the N100 and LPW are influenced differently by serial position during working memory retrieval: N100 shows a primacy effect and LPW demonstrates a recency effect. The results suggest that primacy and recency effects may be mediated by different brain regions at different times during memory retrieval. &

Evidence for Attentional Gradient in the Serial Position Memory Curve from Event-related Potentials

“…Although the P3 component may not be a direct index of storage processes, memory for items that elicit a P3 is better than items that do not elicit a P3, even under task conditions that require immediate or delayed retrieval (Golob & Starr, 2004;Paller, McCarthy, & Wood, 1988). The close relationship of P3 amplitude and delayed retrieval also supports the view that the component is one of the series of processes that reflect the encoding of events for storage in memory.…”

“…Indeed, P300 amplitude increases linearly from probe stimuli of the initial to ending list items, suggesting that recognition primacy and recency effects reflect different processing mechanisms (Golob & Starr, 2004). To date, the majority of studies have assessed serial position in the auditory modality, with no evidence currently available that similar recognition serial position ERP effects occur for visual probes.…”

Speech preparation in adults with persistent developmental stuttering

“…Multiple top-down cognitive factors have been shown to influence the N100 such as attention (Bennett, Golob, & Starr, 2004; Hillyard, Hink, Schwent, & Picton, 1973), short-term memory (Conley, Michalewski, & Starr, 1999; Golob & Starr, 2004), and motor efference copy when speaking (Heinks-Maldonado, Mathalon, Gray, & Ford, 2005; Houde et al, 2002). Also previous studies found hemispheric differences around 100 ms within the auditory cortex of adults who stutter (Beal et al, 2010; Liotti et al, 2010; Salmelin R, Schnitzler A, Schmitz F, Jancke L, Witte OW et al, 1998), whereas the 100 ms group differences found in the current study appear to be bilateral.…”

Correlating digit span performance and event-related potentials to assess working memory

“…In this substantial literature (see Kotchoubey, 2002or Verleger, 1997 for a review), the most consistent finding is the elicitation of a sustained, parietal positivity to the probe (irrespective of probe type) with a monotonous increase in latency as memory set size increases (e.g., Blumhardt, 1996;Pelosi et al, 1992Pelosi et al, , 1995Pelosi et al, , 1998Starr and Barrett, 1987). Moreover, the manifestation of a P300 during the encoding phase has also been found to be a predictor of successful retrieval in the test phase (Chao and Knight, 1996;Golob and Starr, 2004;Kotchoubey et al, 1996;Patterson et al, 1991).…”