The Language Network Is Recruited but Not Required for Nonverbal Event Semantics

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Complex world representations are often linked to language.
• Nonverbal input, like visual scenes, can also form event-level representations.
• The role of the brain's language network in processing nonverbal semantic information is unclear.

Purpose of the Study:

• To investigate if the language network is involved in and necessary for semantic processing of nonverbally presented events.
• To determine if pictorial event comprehension relies on language regions.

Main Methods:

• Experiment 1: fMRI scans during semantic plausibility judgments on sentences and line drawings.
• Experiment 2: Tested individuals with global aphasia and controls on sentence-picture matching and pictorial plausibility tasks.

Main Results:

• The language network showed robust activation during semantic tasks for both sentences and pictures (stronger for sentences).
• Individuals with aphasia were impaired in sentence-picture matching but performed similarly to controls in assessing pictorial plausibility.
• Left frontotemporal language network is recruited but not necessary for nonverbal event semantic processing.

Conclusions:

• The language network is engaged during semantic processing of nonverbal events.
• This engagement is not strictly necessary, indicating nonverbal semantic processing can occur independently of language areas.
• Findings challenge the exclusive association of complex semantic representations with language.