When Wine and Apple Both Help the Production of Grapes: ERP Evidence for Post-lexical Semantic Facilitation in Picture Naming

Abstract

Background: Producing a word in referential naming requires to select the right word in our mental lexicon among co-activated semantically related words. The mechanisms underlying semantic context effects during speech planning are still controversial, particularly for semantic facilitation which investigation remains under-represented in contrast to the plethora of studies dealing with interference. Our aim is to study the time-course of semantic facilitation in picture naming, using a picture-word "interference" paradigm and event-related potentials (ERPs). Methods: We compared two different types of semantic relationships, associative and categorical, in a single word priming and a double word priming paradigm. The primes were presented visually with a long negative Stimulus Onset Asynchrony (SOA), which is expected to cause facilitation. Results: Shorter naming latencies were observed after both associative and categorical primes, as compared to unrelated primes, and even shorter latencies after two primes. Electrophysiological results showed relatively late modulations of waveform amplitudes for both types of primes (beginning ~330 ms post picture onset with a single prime and ~275 ms post picture onset with two primes), corresponding to a shift in latency of similar topographic maps across conditions. Conclusion: The present results are in favor of a post-lexical locus of semantic facilitation for associative and categorical priming in picture naming and confirm that semantic facilitation is as relevant as semantic interference to inform on word production. The post-lexical locus argued here might be related to self-monitoting or/and to modulations at the level of word-form planning, without excluding the participation of strategic processes.

Keywords: ERP; language production; picture naming; response selection; semantic facilitation; semantic priming.

Figure 1

Results for single word priming. (A) Examples of group-averaged waveforms for the UNR-ASS (left) and UNR-CAT (right) contrasts on stimulus-locked ERPs: time-windows of significant clusters over at least four electrodes are highlighted and all electrodes showing the highlighted effect are crossed on the topographical representation. (B) Results of “TANOVA” spatio-temporal analysis for the same contrasts: bars represent time-periods of significant differences in global similarity. (C) Temporal distribution of stable electrophysiological patterns at scalp from the spatio-temporal segmentation on the combined stimulus- and response-locked grand averages matching the actual reaction times of each experimental condition (*indicates a significant difference in map duration).

Figure 2

Results for double word priming. (A) Examples of group-averaged waveforms for the UNR-ASS (left) and UNR-CAT (right) contrasts on stimulus-locked ERPs: time-windows of significant clusters over at least four electrodes are highlighted and all electrodes showing the highlighted effect are crossed on the topographical representations. (B) Results of “TANOVA” spatio-temporal analysis for the same contrasts: bars represent time-periods of significant differences in global similarity. (C) Temporal distribution of stable electrophysiological patterns at scalp from the spatio-temporal segmentation on the combined stimulus- and response-locked grand averages matching the actual reaction times of each experimental condition (*indicates a significant difference in map duration).