Processing linguistic complexity and grammaticality in the left frontal cortex.

We used event-related functional magnetic resonance imaging to directly compare the hemodynamic responses associated with varying degrees of linguistic complexity with those engendered by the processing of ungrammatical utterances. We demonstrate a dissociation within the left inferior frontal cortex between the deep frontal operculum, which responds to syntactic violations, and a core region of Broca's area, that is, the inferior portion of the left pars opercularis in Brodmann area 44, the activation of which is modulated as a function of the complexity of well-formed sentences. The data demonstrate that different brain regions in the prefrontal cortex support distinct mechanisms in the mapping from a linguistic form onto meaning, thereby separating ungrammaticality from linguistic complexity.

"Capacity" reconsidered: interindividual differences in language comprehension and individual alpha frequency.

The influence of interindividual differences in cognitive mechanisms on language comprehension remains controversial not only due to conflicting experimental findings, but also in view of the difficulty associated with determining which measure should be used in participant classification. Here, we address the latter problem by proposing that an electrophysiological measure, individual alpha frequency (IAF), may be a suitable means of classifying interindividual differences in sentence processing. Interindividual differences in IAF have been shown to correlate with performance on memory tasks and speed of information processing.

On the cost of syntactic ambiguity in human language comprehension: an individual differences approach.

We present an event-related brain potential (ERP) study demonstrating that high and low span readers show qualitatively different brain responses in the comprehension of ambiguous and complex linguistic stimuli. During the processing of ambiguous German sentences, low span readers showed a broadly distributed, sustained positivity, whereas high span participants showed a shorter, topographically more focused negativity. Qualitatively similar effects were observable in response to (complex) object-initial sentences.