The breakdown of rapid and accurate retrieval of words is a hallmark of aphasic speech and a prime target of
therapeutic intervention. Complementary, psycho- and neurolinguistic research have developed a spectrum of
models, how and by which neuronal network uncompromised speakers can rely on remarkable lexical retrieval
capacities. Motivated by both lines of research we invited 32 participants with a chronic left hemispheric brain
lesion to name pictures in the presence of distractor words. This ...
The breakdown of rapid and accurate retrieval of words is a hallmark of aphasic speech and a prime target of
therapeutic intervention. Complementary, psycho- and neurolinguistic research have developed a spectrum of
models, how and by which neuronal network uncompromised speakers can rely on remarkable lexical retrieval
capacities. Motivated by both lines of research we invited 32 participants with a chronic left hemispheric brain
lesion to name pictures in the presence of distractor words. This picture-word-interference (PWI) paradigm is
widely used in psycho- and neurolinguistic research.
We find that also after brain lesion categorically related words (CAT → [dog]picture) impede naming, while
associatively related words (BONE → [dog]picture) ease access, when compared to unrelated distractor words. The
effects largely affecting latencies in neurotypical populations, are reproduced for error rate in our participants
with lesions in the language network. Unsurprisingly, overall naming abilities varied greatly across patients. Notably, however, the two effects (categorical interference / associative facilitation) differ between participants.
Correlating performance with lesion patterns we find support for the notion of a divergence of brain areas affording different aspects of the task: (i) lesions in the left middle temporal gyurs (MTG) deteriorate overall naming,
confirming previous work; more notably, (ii) lesions comprising the inferior frontal hub (inferior frontal gyrus,
IFG) of the language-network increase the interference effect for the categorical condition; on the contrary, (iii)
lesions to the mid-to-posterior temporal hub (posterior middle and superior temporal gyri, pMTG/ pSTG) increase
the facilitatory effect for the associative condition on error rates.
The findings can be accommodated in a neuro-linguistic framework, which localizes lexical activation but
also lexical interference in posterior parts of the language network (pMTG/pITG); conversely, selection between
co-activated categorically related entries is afforded by frontal language areas (IFG). While purely experimental
in nature our study highlights that lesion site differentially influences specific aspects of word retrieval. Since confrontational naming is a cornerstone of aphasia rehabilitation, this may be of note when designing and evaluating
novel therapeutic regimes.
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