ERP analysis of cognitive sequencing: a left anterior negativity related to structural transformation processing.

A major objective of cognitive neuroscience is to identify those neurocomputational processes that may be shared by multiple cognitive functions vs those that are highly specific. This problem of identifying general vs specialized functions is of particular interest in the domain of language processing. Within this domain, event related brain potential (ERP) studies have demonstrated a left anterior negativity (LAN) in a range 300-700 ms, associated with syntactic processing, often linked to grammatical function words. These words have little or no semantic content, but rather play a role in encoding syntactic structure required for parsing. In the current study we test the hypothesis that the LAN reflects the operation of a more general sequence processing capability in which special symbols encode structural information that, when combined with past elements in the sequence, allows the prediction of successor elements. We recorded ERPs during a non-linguistic sequencing task that required subjects (n = 10) to process special symbols possessing the functional property defined above. When compared to ERPs in a control condition, function symbol processing elicits a left anterior negative shift between temporal and spatial characteristics quite similar to the LAN described during function word processing in language, supporting our hypothesis. These results are discussed in the context of related studies of syntactic and cognitive sequence processing.