Publications

Abstract

Speaking requires the temporally coordinated planning of core linguistic information, from conceptual meaning to articulation. Recent neurophysiological results suggested that these operations involve a cascade of neural events with subsequent onset times, whilst competing evidence suggests early parallel neural activation. To test these hypotheses, we examined the sources of neuromagnetic activity recorded from 34 participants overtly naming 134 images from 4 object categories (animals, tools, foods and clothes). Within each category, word length and phonological neighbourhood density were co-varied to target phonological/phonetic processes. Multivariate pattern analyses (MVPA) searchlights in source space decoded object categories in occipitotemporal and middle temporal cortex, and phonological/phonetic variables in left inferior frontal (BA 44) and motor cortex early on. The findings suggest early activation of multiple variables due to intercorrelated properties and interactivity of processing, thus raising important questions about the representational properties of target words during the preparatory time enabling overt speaking.

Abstract

Real-time estimation of what we will do next is a crucial prerequisite
of purposive behavior. During the planning of goal-oriented actions, for
instance, the temporal and causal organization of upcoming subsequent
moves needs to be predicted based on our knowledge of events. A forward
computation of sequential structure is also essential for planning
contiguous discourse segments and syntactic patterns in language. The
neural encoding of sequential event knowledge and its domain dependency
is a central issue in cognitive neuroscience. Converging evidence shows
the involvement of a dedicated neural substrate, including the
prefrontal cortex and Broca's area, in the representation and the
processing of sequential event structure. After reviewing major
representational models of sequential mechanisms in action and language,
we discuss relevant neuropsychological and neuroimaging findings on the
temporal organization of sequencing and sequence processing in both
domains, suggesting that sequential event knowledge may be modularly
organized through prefrontal and frontal subregions.