Individual Differences in Lexical Repetition Priming

The current research investigated whether individual differences in working memory capacity (WMC) and affective states have differential effects on lexical-semantic repetition priming outcomes based on whether participants were first- or second-language English speakers. Individual differences in priming effects have often been overlooked in the priming literature. Using logistic mixed-effects models to account for within-subject variation, the current paper investigated a three-way interaction between WMC, negative affect (NA) score, and language primacy on lexical-semantic repetition priming outcomes. The results indicate that a statistically significant three-way interaction exists between language primacy, WMC, and NA scores. No significant interaction effect was found for positive affect scores. We present an argument which posits that an individual's primary language and subsequent familiarity with the primed concepts, in conjunction with individual differences in WMC and mood, plays an important role in determining the most effective strategy used to complete a word-stem completion task. The implications of the findings presented highlight that second-language English speakers are more susceptible to priming effects when prime-inducing stimuli are constructed using English lexicon; however, larger WMC and heighted negative affective states help to mitigate these priming effects.

Pharmacological modulation of behavioral and neuronal correlates of repetition priming

In this experiment we address the pharmacological modulation of repetition priming, a basic form of learning, using event-related functional magnetic resonance imaging. We measured brain activity in a word-stem completion paradigm in which, before study, volunteers were given either placebo, lorazepam (2 mg orally), or scopolamine (0.4 mg, i.v.). Relative to placebo, both drugs attenuated the behavioral expression of priming. Repetition was associated with a decreased neuronal response in left extrastriate, left middle frontal, and left inferior frontal cortices in the placebo group. Both drugs abolished these "repetition suppression" effects. By showing a concurrence of behavioral and neuronal modulations, the results suggest that GABAergic and cholinergic systems influence the neuronal plasticity necessary for repetition priming.

Spatiotemporal maps of brain activity underlying word generation and their modification during repetition priming

Spatiotemporal maps of brain activity based on magnetoencephalography were used to observe sequential stages in language processing and their modification during repetition priming. Subjects performed word-stem completion and produced either novel or repeated (primed) words across trials. Activation passes from primary visual cortex (activated at approximately 100 msec after word presentation), to left anteroventral occipital ( approximately 180 msec), to cortex in and near Wernicke's ( approximately 210 msec) and then Broca's ( approximately 370 msec) areas. In addition, a posteroventral temporal area is activated simultaneously with posterosuperior temporal cortex. This area shows an early ( approximately 200-245 msec) increase in activation to repeated word stems. In contrast, prefrontal and anterior temporal regions showed activity reductions to repeated word stems late ( approximately 365-500 msec) in processing. These results tend to support classical models of language and suggest that an effect of direct item repetition is to allow word-form processing to increase its contribution to task performance while concurrently allowing reductions in time-consuming frontal temporal processing.