Stimulus-driven changes in the direction of neural priming during visual word recognition

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psycholinguistics

Background:

• Priming effects typically facilitate recognition when stimuli are repeated or related.
• However, written word processing exhibits negative syllabic priming, where shared initial syllables can reverse this facilitatory effect.
• Understanding the neural basis of this phenomenon is crucial for models of word recognition.

Purpose of the Study:

• To investigate the neuroanatomical correlates of negative syllabic priming during reading.
• To differentiate the neural mechanisms underlying facilitatory and inhibitory priming effects in word processing.
• To explore the role of the inferior frontal gyrus (IFG) in rapid word processing systems.

Main Methods:

• Two functional magnetic resonance imaging (fMRI) experiments were conducted.
• Participants performed semantic judgments on target words preceded by masked primes (Experiment 1: syllabic priming; Experiment 2: whole-word priming).
• A hemifield presentation procedure was used to control for visual field effects.

Main Results:

• Negative syllabic priming was associated with repetition enhancement in the left inferior frontal gyrus (IFG).
• This contrasts with repetition suppression observed in the ventral visual region for typical facilitatory priming.
• A second experiment confirmed standard repetition suppression in the left occipito-temporal cortex for whole-word priming.

Conclusions:

• The left IFG may host a distinct, rapid word processing system separate from the posterior visual word-form system.
• Repetition effects in word processing can vary based on stimulus properties, such as syllabic overlap.
• Cognitive and attentional states remaining constant suggests stimulus-specific neural responses.