Episodic memory

The purpose of this study was to describe the relationship between mental, physical, and social activity, and episodic memory (EM) of cognitively intact older persons. The specific aims were (a) to describe the relationship between EM and mental, physical, and social activity, (b) to describe the role of gender, marital status, and race on EM, (c) to describe the moderating effects of each activity on the relationship between each of the remaining two activities and EM, and (d) to describe the moderating effects of gender, marital status, and race on the relationship between each activity and EM. Two theoretical frameworks: Cognitive Reserve Theory (Stern, 2002) and Theory of Nursing as Caring (Boykin & Schoenhofer, 1993) guided the study.
This study was designed as a correlational and retrospective secondary analysis of data sets from the Health and Retirement Study. The sample consisted of 3,903 cognitively intact persons who were 50 years and older and completed immediate and delayed recall tests in the 2016 HRS and the 2015 Consumptions and Activities Mail Survey. Descriptive statistics included the means for age: 67 (SD 9.54), education:13.85 (SD 5.89), and total cognition 16.86 (SD 3.11). The sample was predominantly Caucasian (78.3%), female (59.8%), and married (60.9%).

Previous research revealed that episodic memories are more likely to be consolidated if something novel occurs in relative temporal proximity to the original learned event (Dunsmoor, Murty, Davachi, & Phelps, 2015). Further, research conducted with rodents has revealed that novel contextual exposure following encoding of a spatial memory in a food-motivated task results in enhanced consolidation of that spatial memory (Takeuchi, Duszkiewics, Sonneborn et al., 2016). The present study sought to examine the influence of novel context exposure on non-spatial object memory in adult female and male C57BL/6J mice when novel context exposure follows encoding of object memory under two memory strength training protocols. Results revealed that regardless of memory strength or gender, subjects exposed to a novel context following encoding of object memory exhibited greater exploration of the novel object when assessed 23.5 h later. Thus, novel context exposure significantly enhanced the consolidation of recently encoded object memory. As novel context exposure has been shown to increase dopamine release in the hippocampus, these results are consistent with the theory of synaptic tag and capture, whereby activated dopaminergic afferents enhance the on-going consolidation of non-spatial object memory. Future studies will entail parsing potential neurotransmitter modulatory afferents via pharmacological antagonists.