Biomedical subjects

St Heim

Publications and source records attributed to St Heim.

4 recordsLinked to original sources

PubMed2003

Phonological processing in language production: time course of brain activity.

Recent neuroimaging studies provide evidence for a shared neural network for phonological processing in language production and comprehension. The temporal dynamics in this network during comprehension has been investigated by Thierry et al., who showed a primacy for Wernicke's over Broca's area. In the present study, we demonstrate the reversed pattern for language production. These results can be interpreted with respect to the functionality of the different regions within the shared network, with Wernicke's area being the sound form store and Broca's area a processor necessary to extract relevant phonological information from that store.

Adult↗

PubMed2003

Distributed cortical networks for syntax processing: Broca's area as the common denominator.

Different types of syntactic information (word category, grammatical gender) are processed at different times during word recognition. However, it is an open issue which brain systems support these processes. In the present event-related fMRI study, subjects performed either a syntactic gender decision task on German nouns (GEN), a word category decision task (WC, nouns vs. prepositions), or a physical baseline task (BASE). Reaction times in WC were faster than in GEN, supporting earlier electrophysiological results. Relative to BASE, both syntactic tasks activated the inferior tip of BA 44. In addition, BA 45 showed activation in GEN, whereas BA 47 was activated in WC. The imaging data indicate that the inferior portion of BA 44 together with type-specific prefrontal areas supports both initial word category related and later syntactic processes.

Adult↗

PubMed2003

Phonological processing during language production: fMRI evidence for a shared production-comprehension network.

Studies of phonological processes during language comprehension consistently report activation of the superior portion of Broca's area. In the domain of language production, however, there is no unequivocal evidence for the contribution of Broca's area to phonological processing. The present event-related fMRI study investigated the existence of a common neural network for phonological decisions in comprehension and production by using production tasks most comparable to those previously used in comprehension. Subjects performed two decision tasks on the initial phoneme of German picture names (/b/ or not? Vowel or not?). A semantic decision task served as a baseline for both phonological tasks. The contrasts between each phonological task and the semantic task were calculated, and a conjunction analysis was performed. There was significant activation in the superior portion of Broca's area (Brodmann's area (BA) 44) in the conjunction analysis, also present in each single contrast. In addition, further left frontal (BA 45/46) and temporal (posterior superior temporal gyrus) areas known to support phonological processing in both production and comprehension were activated. The results suggest the existence of a shared fronto-temporal neural network engaged in the processing of phonological information in both perception and production.

Adult↗

PubMed2002

Broca's area in the human brain is involved in the selection of grammatical gender for language production: evidence from event-related functional magnetic resonance imaging.

The neural correlates of the selection of grammatical gender during overt picture naming were investigated by event-related functional magnetic resonance imaging in the left hemisphere. Relative to simply naming a picture, the production of the definite determiner of the picture name (requiring gender selection) resulted exclusively in pronounced activation of a single region in the superior portion of Broca's area. This activation was not present in contrasts reflecting lexical access (naming a picture vs. saying "jaja" to a smiley) or articulation (saying "jaja" vs. rest). Rather, lexical access activated other inferior frontal regions, insula, fusiform and inferior temporal gyrus. Articulation involved insula, Rolandic operculum, motor and premotor cortex and superior temporal gyrus. The results are discussed with respect to data from studies investigating gender processing during language comprehension.

Adult↗