Microstructural plasticity following acquired grapheme-colour synaesthesia

Grapheme-colour synaesthesia is the phenomenon where a grapheme is associated with a specific colour (see e.g., Zelazny & Sørensen, 2022). Several neuroimaging studies have attempted to characterise the neural correlate of grapheme-colour synaesthesia, but no consensus has been reached (e.g., Hupé & Dojat, 2015).
However, it has recently been demonstrated that it is possible to measure cortical microanatomic reorganisation after mere minutes of learning new words (Vukovic et al., 2021). In addition, new behavioural research suggests that it may be possible to induce a form of synaesthesia in normal subjects through training (Schwartzman et al., 2019).
In this new experiment, we plan to perform Diffusion Kurtosis Imaging on neurotypical participants before and after a behavioural training session aimed at inducing grapheme-colour synaesthesia. We then examine if the behavioural training reveals changes in kurtosis and diffusivity. In addition, both active and passive control groups will be included in the study.