Memory Binding and Theta EEG During Middle Childhood

• In Event: Poster Session 09
  In Poster Session: PS 09 Topic - Attention, Learning, Memory

Abstract

Episodic memory involves recollection of personally experienced events tagged within a spatial and temporal context (i.e., what-where-when memory; Tulving, 2002). The process of encoding the relations among stimuli and linking the components of an event into a unified and memorable whole is referred to as binding (Chalfonte & Johnson, 1996). The ability to bind together the contextual details associated with an event undergoes dramatic improvement during early childhood (Drummey & Newcombe, 2002; Riggins, 2014; Sluzenski et al., 2006). However, few studies have examined the neural correlates of memory binding encoding and retrieval during middle childhood. In adults, task-related increases in theta power (4 – 7 Hz) are associated with several different memory processes, including episodic encoding and retrieval (Klimesch, 1999). Parietal activation, in particular, is thought to reflect attentional allocation during memory retrieval search processes (Cabeza et al., 2008). However, less is known about the functional role of theta synchronization during childhood. The purpose of our investigation was to (1) examine age-related encoding and retrieval differences in theta EEG activation during a memory binding task in 6- and 8-year-olds and (2) examine individual differences in performance by investigating brain-behavior associations of theta EEG and memory for contextual information.

Participants included twenty-nine 6-year-olds (M = 6.10, SD = .26) and thirty-six 8-year-olds (M = 8.07; SD = .36). For the memory binding task, children were tested on memory for individual items (i.e., objects only, backgrounds only) and combined object-backgrounds pairings (combination condition). The dependent variables of interest were the proportion of hits (i.e., old items correctly identified as old), proportion of false alarms (i.e., new items incorrectly identified as old) and d‘ sensitivity scores for the object, background, and combination conditions. Theta (4 – 7 Hz) neuronal oscillations were analyzed during a baseline period as well as during memory binding encoding and retrieval.

With respect to behavioral results, 6- and 8-year-olds exhibited comparable performance on the proportion of hits for the object, background, and combination conditions. However, 6-year-olds experienced greater difficulty (i.e., higher false alarm rate and lower d’ sensitivity scores) in the combination condition (all ps < .007; See Figure 1). With respect to EEG results, widespread retrieval-related increases in theta band EEG power (compared with baseline and encoding-related activation) were evident in both 6- and 8-year-olds. To examine brain-behavior associations, multiple regression analysis was conducted to examine whether parietal theta EEG contributes to individual variation in memory binding performance. The multiple regression analysis investigating age, verbal IQ proxy, and parietal theta EEG was significant, F(6, 48) = 3.61, p < .01 and accounted for 31% of the variance in memory binding performance (Table 1). These findings suggest that theta rhythms are intricately linked to memory binding processes during middle childhood, potentially reflecting the interaction between cortical structures and hippocampal-dependent binding mechanisms necessary for retrieving the contextual details of a memory episode (Nyhus & Curran, 2010).

Authors

• Vinaya Rajan, University of the Sciences
  Presenting Author

• Kimberly Cuevas, University of Connecticut
  Non-Presenting Author

• Martha Ann Bell, Virginia Polytechnic Institute and State University
  Non-Presenting Author