Mikkel Wallentin
Associate Professor
Center for Semiotics
University of Aarhus
Building 1467
Jens Chr. Skous Vej 7
DK-8000 Aarhus C
DENMARK
Tel. +45 871 63186
LINKS
Center
for Functionally Integrative Neuroscience (CFIN)
The Danish Research Foundation's center for brain imaging at University
of
Aarhus
SFN - Sproglig Forskerskole Nord
Litteratursiden.dk på Forfatternet
RECENT PUBLICATIONS
Wallentin M.
Precuneus – hjernens sproglige rumcenter
Udkommet i: (eds.) Henrik Jørgensen og Peter Widell, Det bedre argument. Festskrift til Ole Togeby 7. marts 2007, Wessel og Huitfeldt, Århus 2007
Wallentin M, Roepstorff A, Glover R, Burgess N.
Parallel memory systems for talking about location and age in precuneus, caudate and Broca's region. NeuroImage 2006; 32: 1850-1864.
ABSTRACT Language comprehension relies on processing of context. Working memory (WM) evoked by linguistic cues for spatial and nonspatial aspects of a visual scene was investigated by correlating fMRI BOLD signal (or ‘activation’) with reaction times (RTs). Subjects were asked to indicate either the relative positions or ages of people or objects (referenced by the personal pronouns “he/she/it”) in a previously shown image. Good performers of a particular task showed shorter RTs than poor performers. Task-specific activation that is greater in good performers than poor ones is taken to indicate involvement of a given region in performance of the task. Our results indicate that dorsoposterior precuneus supports spatial WM during linguistic processing while a network of areas including the caudate support nonspatial WM in categorization of age. We argue that within-subjects variation of RTs across trials reflects effort. Good performers have higher activity in precuneus as a function of effort compared to poor performers during the spatial task, whereas the opposite is found for the nonspatial task, providing further evidence for specifically spatial WM in dorsoposterior precuneus. Task-independent performance-related modulations of activity were found in Broca's area and amygdala. Broca's area activity increased with effort in both tasks, with a greater increase in good performers than in poor performers, consistent with the region's general role in verbal WM. By contrast, activation in amygdala decreased with effort, with a greater decrease in good performers. We take this deactivation to reflect performance-mediating emotional control. These findings indicate that multiple parallel memory systems are available during language processing, appropriate for different tasks, with performance reflecting which system is selected trial-by-trial and subject-by-subject.
Wallentin, M., Lund, T.E., Østergaard, L., Østergaard, S., Roepstorff, A.
(2005):
Motion verb sentences activate left posterior middle temporal cortex despite static context, NeuroReport, vol. 16/6, pp. 649-652
ABSTRACT: The left posterior middle temporal region, anterior toV5/MT, has been shown to be responsive both to images with impliedmotion, to simulatedmotion, and tomotion verbs.
In this study, we investigated whether sentence context alters the response of the left posterior middle temporal region. ‘Fictive motion’ sentences are sentences in which an inanimate subject noun, semantically incapable of self movement, is coupled with a motion verb, yielding an apparent semantic contradiction (e.g. ‘The path comes into the garden.’).
However, this context yields no less activation in the left posteriormiddle temporal region than sentences inwhich themotion can be applied to the subject noun.
We speculate that the left posterior middle temporal region activity in ¢ctive motion sentences re£ects the fact that the hearer applies motion to the depicted scenario by scanning it egocentrically.
Link (pdf): http://www.cfin.au.dk/get_media_file.php?mediaid=425
Wallentin, M., Lund, T.E., Østergaard, L., Østergaard, S., Roepstorff, A.:
Concrete spatial language: See what I mean?
ABSTRACT: Conveying complex mental scenarios is at the heart of human language. Advances in cognitive linguistics suggest this is mediated by an ability to activate cognitive systems involved in non-linguistic processing of spatial information. In this fMRI-study, we compare sentences with a concrete spatial meaning to sentences with an abstract meaning.
Using this contrast, we demonstrate that sentence meaning involving motion in a concrete topographical context, whether linked to animate or inanimate subjects nouns, yield more activation in a bilateral posterior network, including fusiform/parahippocampal, and retrosplenial regions, and the temporal–occipital–parietal junction. These areas have previously been shown to be involved in mental navigation and spatial memory tasks.
Sentences with an abstract setting activate an extended largely left-lateralised network in the anterior temporal, and inferior and superior prefrontal cortices, previously found activated by comprehension of complex semantics such as narratives. These findings support a model of language, where the understanding of spatial semantic content emerges from the recruitment of brain regions involved in non-linguistic spatial processing.