Semantic context and visual feature effects in object naming: an fMRI study using arterial spin labeling.

Area of Science:

• Cognitive Neuroscience
• Psycholinguistics
• Neuroimaging

Background:

• Behavioral studies show naming objects within the same semantic category increases response latencies.
• This semantic context effect is hypothesized to involve verbal self-monitoring and lexico-semantic processing.
• Visual feature similarity can confound interpretations of the semantic context effect.

Purpose of the Study:

• To investigate the neural mechanisms underlying the semantic context effect in object naming.
• To differentiate between semantic and visual feature contributions to the naming latency effect.
• To explore the role of incremental learning and self-monitoring in speech production.

Main Methods:

• Functional magnetic resonance imaging (fMRI) to measure brain perfusion during object naming tasks.
• Behavioral analysis of naming latencies under blocked semantic category conditions.
• Manipulation of visual feature similarity to assess its influence on naming and brain activity.

Main Results:

• Increased naming latencies were observed for categorically related objects, consistent with prior research.
• fMRI data revealed increased bilateral hippocampal and left superior temporal cortex perfusion.
• No perfusion changes were found in the left middle temporal cortex, a region typically linked to lexical-semantic retrieval.
• Perirhinal cortex activity increased for objects with similar visual features, interacting with semantic context.

Conclusions:

• The semantic context effect in object naming is supported by incremental learning mechanisms.
• This effect involves increased demands on verbal self-monitoring.
• Neural activity in the hippocampus and superior temporal cortex reflects semantic processing and self-monitoring during object naming.