Practiced naming of objects and actions: An fMRI study [article]

Ekaterina Delikishkina, Angelika Lingnau, Gabriele Miceli
2019 bioRxiv   pre-print
AbstractWord retrieval deficits are a common problem in patients with stroke-induced brain damage. While complete recovery of language in chronic aphasia is rare, patients' naming ability can be significantly improved by speech therapy. A growing number of neuroimaging studies have tried to pinpoint the neural changes associated with successful outcome of naming treatment. However, the mechanisms supporting naming practice in the healthy brain have received little attention. Yet, understanding
more » ... hese mechanisms is crucial for teasing them apart from functional reorganization following brain damage. To address this issue, we trained a group of healthy monolingual Italian speakers on naming pictured objects and actions for ten consecutive days and scanned them before and after training. Using a combination of univariate and multivariate analyses, we established that object and action naming evoked different responses in lateral occipitotemporal, posterior parietal and left inferior frontal cortices, largely in line with previous findings. However, training of noun and verb production was associated with similar activation changes, encompassing both anterior and posterior regions of the left hemisphere. We argue that while left anterior activation decreases (posterior inferior frontal gyrus, anterior insula) are likely associated with decreased lexical selection demands, training-related activation changes in left parietal and temporal cortices potentially reflect retrieval of knowledge pertaining to trained items from episodic memory (precuneus, angular gyrus) and facilitated access to phonological word forms (posterior superior temporal sulcus).Significance statementFolk wisdom says that practice makes perfect. While the truthfulness of this statement might seem trivial, the underlying brain mechanisms are not yet fully understood. Here we investigate the functional plasticity that accompanies practice-related facilitation following training. We measured the fMRI signal during the production of nouns and verbs from pictures before and after two weeks of intensive naming training. Although activity during object vs. action naming dissociated in a number of regions, training effects for the two word classes were similar and encompassed activation decreases in classical language regions of the left prefrontal cortex. Additionally, MVPA revealed training-related activation changes in posterior areas of the left hemisphere implicated in phonological word storage and episodic memory.
doi:10.1101/590026 fatcat:szvu7rweozbnvok2gdc6f3dyi4