Comprehending the topic of a paragraph: a functional imaging study of a complex language process (original) (raw)

Brain activation during the course of sentence comprehension

Brain and Language, 2006

The purpose of this study is to determine, by functional magnetic resonance imaging, how the activated regions of the brain change as a Japanese sentence is presented in a grammatically correct order. In this study, we presented constituents of a sentence to Japanese participants one by one at regular intervals. The results showed that the left lingual gyrus was signiWcantly activated at the beginning of the sentence, then the left inferior frontal gyrus and left supplementary motor area, in the middle of the sentence, and the left inferior temporal gyrus, at the end of the sentence. We suggest that these brain areas are involved in sentence comprehension in this temporal order.

Functional magnetic resonance imaging (fMRI) during a language comprehension task

Journal of Neurolinguistics, 2003

Previous magnetoencephalography (MEG) studies in healthy right-handed subjects have shown activation in the left posterior lateral aspect of temporal lobe accompanied by sources in the supramarginal gyrus (Broadmann areas 21,22) during language comprehension tasks. We used the method of functional magnetic resonance imaging to determine whether a similar comprehension task in which participants had to discriminate between feminine and neuter abstract nouns elicited activation in the same regions of the temporal lobes. A baseline condition was also used that required participants to discriminate between two different pitch tones. All six subjects showed significant activity in left superior and middle temporal gyrus (Broadmann areas 21,22) and five of them showed maximum activation in this area. Our results are in agreement with those of the MEG studies, demonstrating the concordance of the two methods and the validity of this task.

Brain activation in discourse comprehension: A 3t fMRI study

Neuroimage, 2008

To date a very small number of functional neuroimaging studies have specifically examined the effects of story coherence on brain activation using long narratives, a procedure fundamental to the study of global coherence. These studies, however, not only yielded notably divergent results, but also featured a number of caveats. It is the purpose of the present study to try to overcome some of these limitations. A left precuneus/posterior cingulate activation related to global coherence comprehension was in consonance with a part of previous literature. However, our most important results corresponded to left parietal regions (angular gyrus, BA 39), this diverging from the previous studies. Recent developments of the situational models of narrative comprehension could explain all these apparently inconsistent results. According to these, different situation models would be created as a function of the content of the narratives, which would yield in turn different patterns of brain activity. Our data also suggest that the same content might also give place to different situation models as a function of the degree of global coherence achieved by the reader or listener.

Processing of Visually Presented Sentences in Mandarin and English Studied with fMRI

Neuron, 1999

. However, it remains unclear whether these lexicons are spatially segregated within the brain. The case for anatomically segregated lexicons is suggested * Cognitive Neuroscience Laboratory by clinical case studies of individuals who experience Singapore General Hospital dissociated language loss following brain damage (Al-Singapore 169856 bert and Obler, 1978) as well some data from electrical † Department of Social Work and Psychology stimulation of the brain (Ojemann and Whitaker, 1978; National University of Singapore ). An alternative explanation for the Singapore 119260 loss or preferential recovery of one language in a bilin- ‡ Neuropsychology Laboratory gual postulates disruption of a control system that allo-Department of Neurology cates resources to one or the other language (Green, 1986; Massachusetts General Hospital Paradis, 1998). Under this framework, spatially segre-Boston, Massachusetts 02114 gated lexicons are not required to explain dissociated § Department of Radiology language loss or recovery. University of Freiburg Neuroimaging studies of language function in healthy D79106 Freiburg bilingual subjects have sought to demonstrate neural Federal Republic of Germany substrates responsible for bilingual language processing. Department of Psychology However, the work to date has yielded conflicting re-University of Kent sults. At the single word level, several studies report Canterbury CT27LZ overlapping activations in two languages (Klein et al., United Kingdom 1994, 1995; Chee et al., 1999), whereas, at the sentence level, intrahemispheric differences in left hemisphere activations as well as occasional interhemispheric dif-Summary ferences have been reported (Mazoyer et al., 1993; Perani et al., 1996; Dehaene et al., 1997; Kim et al., 1997).

The Neural Bases of Sentence Comprehension: a fMRI Examination of Syntactic and Lexical Processing

Cerebral Cortex, 2001

One of the challenges to functional neuroimaging is to understand how the component processes of reading comprehension emerge from the neural activity in a network of brain regions. In this study, functional magnetic resonance imaging (fMRI) was used to examine lexical and syntactic processing in reading comprehension by independently manipulating the cognitive demand on each of the two processes of

Spatial and temporal analysis of fMRI data on word and sentence reading

European Journal of Neuroscience, 2007

Written language comprehension at the word and the sentence level was analysed by the combination of spatial and temporal analysis of functional magnetic resonance imaging (fMRI). Spatial analysis was performed via general linear modelling (GLM). Concerning the temporal analysis, local differences in neurovascular coupling may confound a direct comparison of blood oxygenation leveldependent (BOLD) response estimates between regions. To avoid this problem, we parametrically varied linguistic task demands and compared only task-induced within-region BOLD response differences across areas. We reasoned that, in a hierarchical processing system, increasing task demands at lower processing levels induce delayed onset of higher-level processes in corresponding areas. The flow of activation is thus reflected in the size of task-induced delay increases. We estimated BOLD response delay and duration for each voxel and each participant by fitting a model function to the event-related average BOLD response. The GLM showed increasing activations with increasing linguistic demands dominantly in the left inferior frontal gyrus (IFG) and the left superior temporal gyrus (STG). The combination of spatial and temporal analysis allowed a functional differentiation of IFG subregions involved in written language comprehension. Ventral IFG region (BA 47) and STG subserve earlier processing stages than two dorsal IFG regions (BA 44 and 45). This is in accordance with the assumed early lexical semantic and late syntactic processing of these regions and illustrates the complementary information provided by spatial and temporal fMRI data analysis of the same data set.

Engagement of right temporal cortex during processing of linguistic context

Neuropsychologia, 2001

Language processing involves the interplay of areas in both cerebral hemispheres. Whereas the left temporal lobe is necessary for most language tasks, the right hemisphere seems to be additionally activated during processing of paragraphs and metaphors. We studied the neural correlates of word generation and selection in a sentence context, using functional magnetic resonance imaging (fMRI). Cerebral activation was measured while seven healthy, right handed volunteers read and completed sentence stems, with relatively low Cloze frequency, out loud. During a GENERATION condition, subjects were required to generate a word which completed a sentence stem appropriately. During a DECISION condition, subjects selected and articulated one of two presented terminal words. A READING condition in which subjects read an appropriate completion aloud, served as baseline. When GENERATION was compared to READING or DECISION, the left middle frontal, anterior cingulate, precuneus and right lateral temporal cortex were activated. During DECISION relative to READING, the left inferior frontal and middle/superior temporal cortex bilaterally were activated. The prominent engagement of the right lateral temporal cortex during the GENERATION conditions may reflect the processing of linguistic context, and particularly the activation of multiple meanings in the course of producing an appropriate completion.

The cortical organization of audio-visual sentence comprehension: an fMRI study at 4 Tesla

Cognitive Brain Research, 2004

Neuroimaging studies of written and spoken sentence processing report greater left hemisphere than right hemisphere activation. However, a large majority of our experience with language is face-to-face interaction, which is much richer in information. The current study examines the neural organization of audiovisual (AV) sentence processing using functional magnetic resonance imaging (fMRI) at 4 Tesla. Participants viewed the face and upper body of a speaker via a video screen while listening to her produce, in alternating blocks, English sentences and sentences composed of pronounceable non-words. Audiovisual sentence processing was associated with activation in the left hemisphere in Broca's area, dorsolateral prefrontal cortex, the superior precentral sulcus, anterior and middle portions of the lateral sulcus, middle superior portions of the temporal sulcus, supramarginal gyrus and angular gyrus. Further, AV sentence processing elicited activation in the right anterior and middle lateral sulcus. Between-hemisphere analyses revealed a left hemisphere dominant pattern of activation. The findings support the hypothesis that the left hemisphere may be biased to process language independently of the modality through which it is perceived. These results are discussed in the context of previous neuroimaging results using American Sign Language (ASL).

Time Course of fMRI-Activation in Language and Spatial Networks during Sentence Comprehension

NeuroImage, 1999

Functional neuroimaging previously has been considered to provide inadequate temporal resolution to study changes of brain states as a function of cognitive computations; however, we have obtained evidence of differential amounts of brain activity related to high-level cognition (sentence processing) within 1.5 s of stimulus onset. The study used an event-related paradigm with high-speed echoplanar functional magnetic resonance imaging (fMRI) to trace the time course of the brain activation in the temporal and parietal regions as participants comprehended single sentences describing a spatial configuration. Within the first set of images, on average 1 s from when the participant begins to read a sentence, there was significant activation in a key cortical area involved in language comprehension (the left posterior temporal gyrus) and visuospatial processing (the left and right parietal regions). In all three areas, the amount of activation during sentence comprehension was higher for negative sentences than for their affirmative counterparts, which are linguistically less complex. The effect of negation indicates that the activation in these areas is modulated by the difficulty of the linguistic processing. These results suggest a relatively rapid coactivation in both linguistic and spatial cortical regions to support the integration of information from multiple processing streams.

A functional MRI analysis of comprehension processes of Japanese sentences

NeuroReport, 1998

WE tried to identify the mechanisms directly related to syntactic processing in an fMRI experiment using strictly controlled sets of verbal stimuli. In two conditions, center-embedding and left-branching conditions, the same sets of words were used to construct stimulus sentences, while only the word order reflecting their syntactic structure was different. The subject's task was to understand the relationship among three characters mentioned in the sentences. A difference of activation in Broca's area (BA44 and 45) between the two conditions was found. This result suggests that these areas are involved in syntax-related processing. Furthermore, it was suggested that the posterior part of the frontal lobe (BA6/9) and the inferior parietal area (BA39/40) are involved in the understanding of the relationship among the three characters mentioned in each sentence.