Linear spatial integration for single-trial detection in encephalography.

Conventional analysis of electroencephalography (EEG) and magnetoencephalography (MEG) often relies on averaging over multiple trials to extract statistically relevant differences between two or more experimental conditions. In this article we demonstrate single-trial detection by linearly integrating information over multiple spatially distributed sensors within a predefined time window. We report an average, single-trial discrimination performance of Az approximately 0.80 and faction correct between 0.70 and 0.80, across three distinct encephalographic data sets. We restrict our approach to linear integration, as it allows the computation of a spatial distribution of the discriminating component activity. In the present set of experiments the resulting component activity distributions are shown to correspond to the functional neuroanatomy consistent with the task (e.g., contralateral sensorymotor cortex and anterior cingulate). Our work demonstrates how a purely data-driven method for learning an optimal spatial weighting of encephalographic activity can be validated against the functional neuroanatomy

The Influence of Focus Operators on Syntactic Processing of Short Relative Clause Sentences

Ni, Crain, and Shankweiler (1996) present evidence to suggest that the focus operator only can guide how reduced relative clause sentences are initially parsed. In this paper, we demonstrate that this does not hold for relative clause sentences that start with a noun-phrase, verb, noun-phrase construction. We report an eye movement study in which subjects read reduced and unreduced sentences of this type with and without the focus operator only. There were longer first-pass reading times in the critical region of reduced sentences than in the same region of unreduced sentences, regardless of the inclusion of only. Furthermore, readers spent less time re-inspecting portions of text after being garden pathed when reading reduced relative clause sentences that contained the focus operator than when reading reduced relative clause sentences that did not. We conclude that subjects initially syntactically misanalysed reduced relative clause sentences with and without only, and the inclusion of a focus operator facilitated recovery procedures rather than guiding initial parsing. These results are inconsistent with the referential theory and undermine the conclusions of Ni et al. (1996)