Priming Picture Naming with a Semantic Task: An fMRI Investigation

Shiree Heath,Anna Macdonald,Kori Johnson,Katie Mcmahon,David Copland,Lyndsey Nickels,Sophia Van Hees,Anthony Angwin,Celia Oreja-Guevara

doi:10.1371/journal.pone.0032809

Abstract

Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms.

Highlights

In the treatment of word retrieval difficulties associated with post-stroke aphasia, both phonological and semantic tasks have been found to be effective [1]
It has been argued that certain normal brain mechanisms may underpin aspects of aphasia recovery [3] and that successful treatment of word retrieval may rely on the same mechanisms that underlie priming in unimpaired naming [4]
The present study, aimed to examine in healthy older adults the effects associated with a typical semantic facilitation technique on subsequent picture naming performance using functional magnetic resonance imaging

Summary

Introduction

In the treatment of word retrieval difficulties associated with post-stroke aphasia, both phonological and semantic tasks have been found to be effective [1]. It has been argued that certain normal brain mechanisms may underpin aspects of aphasia recovery [3] and that successful treatment of word retrieval may rely on the same mechanisms that underlie priming in unimpaired naming [4]. The present study, aimed to examine in healthy older adults the effects associated with a typical semantic facilitation technique on subsequent picture naming performance using functional magnetic resonance imaging (fMRI). This is vital to elucidate the mechanisms underpinning aphasia treatment success, and to further our understanding of the mechanisms of facilitation in the unimpaired brain

Results

Discussion

Conclusion