Brain Imaging Investigation of the Memory-Enhancing Effect of Emotion

Summary

We present a protocol that uses functional magnetic resonance imaging to investigate the neural correlates of the memory-enhancing effect of emotion. This protocol allows identification of brain activity specifically linked to memory-related processing, contrary to more general perceptual processing, and can be used with healthy and clinical populations.

Abstract

Emotional events tend to be better remembered than non-emotional events^1,2. One goal of cognitive and affective neuroscientists is to understand the neural mechanisms underlying this enhancing effect of emotion on memory. A method that has proven particularly influential in the investigation of the memory-enhancing effect of emotion is the so-called subsequent memory paradigm (SMP). This method was originally used to investigate the neural correlates of non-emotional memories³, and more recently we and others also applied it successfully to studies of emotional memory (reviewed in^{4, 5-7}). Here, we describe a protocol that allows investigation of the neural correlates of the memory-enhancing effect of emotion using the SMP in conjunction with event-related functional magnetic resonance imaging (fMRI). An important feature of the SMP is that it allows separation of brain activity specifically associated with memory from more general activity associated with perception. Moreover, in the context of investigating the impact of emotional stimuli, SMP allows identification of brain regions whose activity is susceptible to emotional modulation of both general/perceptual and memory-specific processing. This protocol can be used in healthy subjects^8-15, as well as in clinical patients where there are alterations in the neural correlates of emotion perception and biases in remembering emotional events, such as those suffering from depression and post-traumatic stress disorder (PTSD)^{16, 17}.

Protocol

1. Experimental Design, Methodological Issues, & Stimuli

The SMP consist of two tasks, an encoding task and a retrieval task, and recording of brain activity may occur during the encoding task or during both encoding and retrieval tasks (see Figure 1 for a diagram illustrating the design of the SMP).

Figure 1. General Diagram of the SMP design. Brain regions whose ac....

Discussion

This experimental protocol allows investigation of the neural correlates of the memory-enhancing effect of emotion, by specifically separating the memory-related brain activity that is susceptible to modulation by emotion from activity in brain regions susceptible to emotion modulation during general/perceptual processing. This design has been instrumental in advancing our understanding of the neural mechanisms underlying the impact of emotion on memory, and given its versatility it is expected that SMP will remain cr.......