Activation of stimulus-specific processing regions at retrieval tracks the strength of relational memory.

Brion Woroch,Alex Konkel,Brian D Gonsalves

doi:10.3934/neuroscience.2019.4.250

Abstract

Many theories of episodic memory posit that the subjective experience of recollection may be driven by the activation of stimulus-specific cortical regions during memory retrieval. This study examined cortical activation during associative memory retrieval to identify brain regions that support confidence judgments of source memory in stimulus-specific ways. Adjectives were encoded with either a picture of a face or a scene. During a source memory test, the word was presented alone and the participant was asked if the word had been previously paired with a face or a scene. We identified brain regions that were selectively active when viewing pictures of scenes or faces with a separate localizer scan. We then identified brain regions that were differentially activated to words during the source memory test that had been previously paired with faces or scenes, masked by the localizer activations, and examined how those regions were modulated by the strength of the source memory. Bilateral amygdala activation tracked source memory confidence for faces, while parahippocampal cortex tracked source memory confidence for scenes. The magnitude of the activation of these domain-specific perceptual-processing brain regions during memory retrieval may contribute to the subjective strength of episodic recollection.

Highlights

Memory for episodes from one’s past involves the coordination of multiple brain systems at the time of encoding and again during memory retrieval
This study examined cortical activation during associative memory retrieval to identify brain regions that support confidence judgments of source memory in stimulus-general and stimulusspecific ways
We hypothesized that the magnitude of activation of stimulus-specific processing brain regions during a source memory task would scale with confidence for that specific kind of information

Summary

Introduction

Memory for episodes from one’s past involves the coordination of multiple brain systems at the time of encoding and again during memory retrieval These include cortical regions that process the components of an episode such as the people that were present, the time the event took place, or the setting in which the episode occurred. Structures in the medial temporal lobe (MTL), most notably the hippocampus, act to bind together these various elements of experience into a coherent episodic memory [1,2]. This specific episodic memory can be retrieved in response to a cue from one aspect of the memory, allowing inspection and re-experiencing of the entire original episode. The aim of the current study was to investigate perceptual brain regions that are activated during source memory retrieval and how this activation contributes to the remembering of different stimulus types, and how activation in these regions tracks the subjective strength of memory for specific stimulus types

Methods

Results

Conclusion