Age differences in medial prefrontal activity for subsequent memory of truth value

Brittany S Cassidy,Carolyn Yoon,Angela H Gutchess,Trey Hedden

doi:10.3389/fpsyg.2014.00087

Abstract

Much research has demonstrated that aging is marked by decreased source memory relative to young adults, yet a smaller body of work has demonstrated that increasing the socioemotional content of source information may be one way to reduce age-related performance differences. Although dorsomedial prefrontal cortex (dmPFC) activity may support source memory among young and older adults, the extent to which one activates dorsal vs. ventral mPFC may reflect one's personal connection with incoming information. Because truth value may be one salient marker that impacts one's connection with information and allocation of attention toward incoming material, we investigated whether the perceived truth value of information differently impacts differences in mPFC activity associated with encoding source information, particularly with age. Twelve young (18–23 years) and 12 older adults (63–80 years) encoded true and false statements. Behavioral results showed similar memory performance between the age groups. With respect to neural activity associated with subsequent memory, young adults, relative to older adults, exhibited greater activity in dmPFC while older adults displayed enhanced ventromedial prefrontal cortex (vmPFC) and insula engagement relative to young. These results may potentially indicate that young adults focus on a general knowledge acquisition goal, while older adults focus on emotionally relevant aspects of the material. The findings demonstrate that age-related differences in recruitment of mPFC associated with encoding source information may in some circumstances underlie age-equivalent behavioral performance.

Highlights

In addition to remembering the information itself, some of the most important choices in life require consideration of the context related to incoming information, often referred to as source memory (Johnson and Raye, 1981; Johnson et al, 1993)
A small body of behavioral evidence shows that increasing task salience, or the degree of importance of a task to an individual, may reduce age differences in source memory (e.g., Rahhal et al, 2002; but see Siedlecki et al, 2005), in contrast with the age-related source memory impairments shown for tasks across several domains of stimuli that utilize less salient and non-social material (e.g., Spencer and Raz, 1995)
The present study explored whether young and older adults differentially engage dorsomedial prefrontal cortex (dmPFC) and ventromedial prefrontal cortex (vmPFC) for the value-rich task of encoding truth value, be it inferred from a social source or explicitly stated

Summary

Introduction

In addition to remembering the information itself, some of the most important choices in life require consideration of the context related to incoming information, often referred to as source memory (Johnson and Raye, 1981; Johnson et al, 1993). Purported truth might be one salient factor driving prioritization of information at encoding, and may reduce age differences in source memory, given the inherent value of knowing whether information is true While both the National Enquirer and The New York Times are sources of information, people may perceive non-tabloid journalism as more truthful, and more deeply encode this information. For example, learn the same piece of information from a gossiping coworker known to spread rumors, or from a trusted friend; you may allocate more attention to your friend due to the perceived reliability of that source This prioritization in encoding strategies suggests that source memory, or remembering the context in which information was presented, may directly relate to how we process information obtained from our daily interactions

Methods

Results

Conclusion