The functional relationship between language and motor processing in typewriting: An EEG study

Scaltritti, M. . 1 , Pinet, S. 1 , Longcamp, M. . 2 & Alario, F. 1

1 LPC UMR 7290, Aix-Marseille Université , CNRS, France
2 LNC UMR 7291, Aix-Marseille Université, CNRS, France

There is growing interest in understanding the functional relationship between language and motor processing during language production. We addressed this issue using event-related potentials recorded during a typewriting task. Linguistic processes were indexed by the N400 component. Motor processes were indexed by lateralized response-related potentials. In this way, we combined two time-honoured psychophysiological markers within a single innovative experiment. At stake was the relationship between the two markers.
The experiment consisted in a semantic-priming paradigm, with written prime-words briefly presented before auditory target-words. We manipulated factorially the Semantic Relatedness between primes and targets (Related vs. Unrelated), and Response Side (first two letters of the targets typed with Right vs. Left hand).
The standard N400 effect was replicated, with an attenuation of the negative going potential in the Related compared to the Unrelated condition. Response Side yielded lateralized potentials traditionally linked with motor-response preparation, consisting in negative-going components over electrodes contralateral to the responding hand, and more positive-going ones over ipsilateral electrodes. The two manipulations yielded independent effects, with no signs of statistical interaction.
These results are in line with a staged account of the transition from language to motor processes during language production. The scope of this interpretation is discussed.