Authors:

PULVERMÜLLER, F. & SHTYROV, Y.

Reference:

Year of publication:

2001

CBU number:

5176

Abstract:

Neurophysiological correlates of syntactic processing were investigated while subjects attended to silent movies. Grammatical and ungrammatical spoken word strings (we come vs. *we comes) were physically identical up to a divergence point where the grammatical string terminated but the ungrammatical one continued in a final -s. In Experiment 1, the grammatical string was presented as a deviant stimulus (p=16%) against the background of ungrammatical strings (84% standard), and in Experiment 2, the ungrammatical string was the deviant in the reversed design. 64 channel EEG recordings revealed differential mismatch responses to the grammatical and ungrammatical strings starting already 100-150 ms after the stimuli's divergence point. The ungrammatical deviant elicited an early and left-lateralized MMN maximal at fronto-central recordings (FC-line), a short sharp positive deflection immediately thereafter, around 150-200 ms, maximal at centro-parietal loci (CP line) and another fronto-central negativity maximal between 350 and 400 ms. Instead, the grammatical string produced a less pronounced and relatively flat MMN with fronto-central distribution. One may ask whether these differences indeed relate to grammatical processing, and not to differences of physical parameters, words, or affixes. Therefore the physiological difference between "we come" and "we comes" was compared to that obtained between "come" and "comes" alone. Significant Context x Affixation interactions confirmed the conclusion that modulations of the early left-anterior negativity, the sharp positivity, and the late negativity indicate grammatical processing.