Suggestion-Induced Modulation of Semantic Priming during Functional Magnetic Resonance Imaging.

Martin Ulrich,Klaus Hoenig,Markus Kiefer,Georg Grön,Walter Bongartz,Xi Luo

doi:10.1371/journal.pone.0123686

Abstract

Using functional magnetic resonance imaging during a primed visual lexical decision task, we investigated the neural and functional mechanisms underlying modulations of semantic word processing through hypnotic suggestions aimed at altering lexical processing of primes. The priming task was to discriminate between target words and pseudowords presented 200 ms after the prime word which was semantically related or unrelated to the target. In a counterbalanced study design, each participant performed the task once at normal wakefulness and once after the administration of hypnotic suggestions to perceive the prime as a meaningless symbol of a foreign language. Neural correlates of priming were defined as significantly lower activations upon semantically related compared to unrelated trials. We found significant suggestive treatment-induced reductions in neural priming, albeit irrespective of the degree of suggestibility. Neural priming was attenuated upon suggestive treatment compared with normal wakefulness in brain regions supporting automatic (fusiform gyrus) and controlled semantic processing (superior and middle temporal gyri, pre- and postcentral gyri, and supplementary motor area). Hence, suggestions reduced semantic word processing by conjointly dampening both automatic and strategic semantic processes.

Highlights

According to classical theories, higher-level top-down influences like attentional control or task set configurations are believed to be restricted to conscious processing
Comparing masked with unmasked primes, we recently reported data supportive of the notion that the automatic aspects of semantic priming elicited by unconsciously perceived masked primes most likely involve a portion of the left fusiform gyrus (FFG) while the bilateral superior temporal gyri (STG), the pre- and postcentral gyri (PrG, PoG), the supplementary motor area proper (SMA proper), and the superior parietal lobules (SPL) were most likely involved in strategic processes tied to supraliminal priming, such as semantic matching [27]
Statistical parametric maps resulting from the analyses described above were thresholded at p < 0.005 at the voxel level in combination with a cluster extent threshold that required cluster sizes of contiguously significant voxels to survive a level of p < 0.050, corrected for multiple comparisons using the topographical false discovery rate (FDR) correction method [37]

Summary

Introduction

Higher-level top-down influences like attentional control or task set configurations are believed to be restricted to conscious processing. Early refined models of automaticity suggest that the occurrence of automatic processes might rely on specific configurations of the cognitive system [3]. In extension of these suggestions Kiefer and colleagues developed the attentional sensitization model of unconscious cognition and have recently shown that the occurrence of a certain automatic process depends on prior sensitization of the cognitive system for instance by specific. Suggestion-Induced Modulation of Semantic Priming conscious and unconscious visual perception” (PAK 270/2) to Markus Kiefer (DFG Ki 804/3-2). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Results

Discussion

Conclusion