scholarly journals Dissociating semantic and phonological contributions of the left inferior frontal gyrus to language production

2019 ◽  
Author(s):  
Jana Klaus ◽  
Gesa Hartwigsen
Keyword(s):  
Phonological Processing ◽  
Language Production ◽  
Semantic Processing ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Inferior Frontal Gyrus ◽  
Control Site ◽  
Generation Task ◽  
Left Inferior Frontal Gyrus ◽  
Functional Relevance ◽  
Naming Latencies

While the involvement of the left inferior frontal gyrus (IFG) in language production is undisputed, the role of specific subregions at different representational levels remains unclear. Some studies suggest a division of anterior and posterior regions for semantic and phonological processing, respectively. Crucially, evidence thus far only comes from correlative neuroimaging studies, but the functional relevance of the involvement of these subregions during a given task remains elusive. We applied repetitive transcranial magnetic stimulation (rTMS) over anterior and posterior IFG (aIFG/pIFG), and vertex as a control site, while participants performed a category member and a rhyme generation task. We found a functional-anatomical double dissociation between tasks and subregions. Naming latencies were significantly delayed in the semantic task when rTMS was applied to aIFG (relative to pIFG and vertex). In contrast, we observed a facilitation of naming latencies in the phonological task when rTMS was applied to pIFG (relative to aIFG and vertex). The results provide first causal evidence for the notion that anterior portions of the IFG are selectively recruited for semantic processing while posterior regions are functionally specific for phonological processing during word production. These findings shed light on the functional parcellation of the left IFG in language production.

scholarly journals The left posterior inferior frontal gyrus is functionally relevant for grammatical processing guided by intonation

2021 ◽  
Author(s):  
Constantijn L van der Burght ◽  
Ole Numssen ◽  
Benito Schlaak ◽  
Tomás Goucha ◽  
Gesa Hartwigsen
Keyword(s):  
Sentence Processing ◽  
Semantic Processing ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Inferior Frontal Gyrus ◽  
Inhibitory Effect ◽  
Syntactic Processing ◽  
Sentence Completion ◽  
Facilitation Effect ◽  
Prosodic Cues ◽  
Functional Relevance

Auditory language comprehension involves processing the content (semantics), grammar (syntax), and intonation (prosody) of a sentence. Sentence processing guided by prosody has been shown to involve the left inferior frontal gyrus (IFG). Prosodic cues are known to interact closely with both syntax and semantics, yet, whether these two processing domains can be attributed to separate subregions within the left IFG is highly debated. We probed the causal role of the posterior IFG (pIFG) for syntactic processing and the anterior IFG (aIFG) for semantic processing in a task that required the interpretation of the sentence’s prosodic realisation. Healthy participants performed a sentence completion task with syntactic and semantic decisions, while receiving 10 Hz repetitive transcranial magnetic stimulation (rTMS) over either left aIFG, pIFG, or vertex (control). Although the behavioural analysis showed no significant interaction between rTMS site and decision, electrical field simulations revealed a task-specific facilitation effect: stronger pIFG stimulation led to faster syntactic processing without significantly modulating semantic decisions. In contrast, aIFG stimulation had an unspecific inhibitory effect. These results provide evidence for the functional relevance of left pIFG in grammatical processing guided by intonation. The unspecific inhibitory effect of aIFG rTMS highlights this subregion’s role in domain-general processes.

scholarly journals Prefrontal Cortical Response to Conflict during Semantic and Phonological Tasks

2007 ◽  
Vol 19 (5) ◽  
pp. 761-775 ◽  
Author(s):  
Hannah R. Snyder ◽  
Keith Feigenson ◽  
Sharon L. Thompson-Schill
Keyword(s):  
Prefrontal Cortex ◽  
Cognitive Control ◽  
Phonological Processing ◽  
Functional Organization ◽  
Inferior Frontal Gyrus ◽  
General Function ◽  
Left Inferior Frontal Gyrus ◽  
Domain Specific ◽  
Prefrontal Cortical ◽  
Specific Effects

Debates about the function of the prefrontal cortex are as old as the field of neuropsychology—often dated to Paul Broca's seminal work. Theories of the functional organization of the prefrontal cortex can be roughly divided into those that describe organization by process and those that describe organization by material. Recent studies of the function of the posterior, left inferior frontal gyrus (pLIFG) have yielded two quite different interpretations: One hypothesis holds that the pLIFG plays a domain-specific role in phonological processing, whereas another hypothesis describes a more general function of the pLIFG in cognitive control. In the current study, we distinguish effects of increasing cognitive control demands from effects of phonological processing. The results support the hypothesized role for the pLIFG in cognitive control, and more task-specific roles for posterior areas in phonology and semantics. Thus, these results suggest an alternative explanation of previously reported phonology-specific effects in the pLIFG.

Contemporary model of language organization: an overview for neurosurgeons

2015 ◽  
Vol 122 (2) ◽  
pp. 250-261 ◽  
Author(s):  
Edward F. Chang ◽  
Kunal P. Raygor ◽  
Mitchel S. Berger
Keyword(s):  
Speech Processing ◽  
Phonological Processing ◽  
Semantic Processing ◽  
Functional Organization ◽  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Functional Neuroanatomy ◽  
Additional Information ◽  
Dorsal Pathway ◽  
Subcortical Mapping

Classic models of language organization posited that separate motor and sensory language foci existed in the inferior frontal gyrus (Broca's area) and superior temporal gyrus (Wernicke's area), respectively, and that connections between these sites (arcuate fasciculus) allowed for auditory-motor interaction. These theories have predominated for more than a century, but advances in neuroimaging and stimulation mapping have provided a more detailed description of the functional neuroanatomy of language. New insights have shaped modern network-based models of speech processing composed of parallel and interconnected streams involving both cortical and subcortical areas. Recent models emphasize processing in “dorsal” and “ventral” pathways, mediating phonological and semantic processing, respectively. Phonological processing occurs along a dorsal pathway, from the posterosuperior temporal to the inferior frontal cortices. On the other hand, semantic information is carried in a ventral pathway that runs from the temporal pole to the basal occipitotemporal cortex, with anterior connections. Functional MRI has poor positive predictive value in determining critical language sites and should only be used as an adjunct for preoperative planning. Cortical and subcortical mapping should be used to define functional resection boundaries in eloquent areas and remains the clinical gold standard. In tracing the historical advancements in our understanding of speech processing, the authors hope to not only provide practicing neurosurgeons with additional information that will aid in surgical planning and prevent postoperative morbidity, but also underscore the fact that neurosurgeons are in a unique position to further advance our understanding of the anatomy and functional organization of language.

scholarly journals Effect of Repetitive Transcranial Magnetic Stimulation on the Right Superior Temporal Gyrus for Severe Aphasia Caused by Damage to the Left Inferior Frontal Gyrus

2019 ◽  
Vol 11 (2) ◽  
pp. 189-198 ◽  
Author(s):  
Mimpei Kawamura ◽  
Nobuhiro Takahashi ◽  
Yasutaka Kobayashi
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Inferior Frontal Gyrus ◽  
Low Frequency ◽  
Superior Temporal Gyrus ◽  
Verbal Expression ◽  
Left Inferior Frontal Gyrus ◽  
The Right ◽  
Low Frequency Rtms

Several reports on repetitive transcranial magnetic stimulation (rTMS) for the treatment of aphasia caused by damage to the left inferior frontal gyrus state that low-frequency rTMS therapy for the right inferior frontal gyrus, which is contralateral to the focus area, is effective for improving verbal expression. However, most of these reports have studied the effects of rTMS therapy for comparatively mild aphasia. This study attempted to perform low-frequency rTMS on the right posterior superior temporal gyrus (BA22), which is the center for language reception for aphasia patients with a drastic decline in verbal expression due to damage to the left inferior frontal gyrus and a considerable decline in language perception. The participants performed a language task that was displayed on a computer monitor during rTMS. In addition, intensive speech-language and hearing therapy was performed by the therapist after rTMS. This study reports that a resultant improvement in language perception was observed in the activated brain regions based on neuropsychological tests and functional magnetic resonance imaging. This study is considered to be significant as it highlights a new method of rTMS treatment for severe aphasia.

scholarly journals Hearing and seeing meaning in speech and gesture: insights from brain and behaviour

2014 ◽  
Vol 369 (1651) ◽  
pp. 20130296 ◽  
Author(s):  
Aslı Özyürek
Keyword(s):  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Semantic Integration ◽  
Electrophysiological Recording ◽  
Arbitrary Form ◽  
Left Inferior Frontal Gyrus ◽  
Iconic Gesture ◽  
Speech Segment ◽  
Posterior Superior Temporal Sulcus

As we speak, we use not only the arbitrary form–meaning mappings of the speech channel but also motivated form–meaning correspondences, i.e. iconic gestures that accompany speech (e.g. inverted V-shaped hand wiggling across gesture space to demonstrate walking). This article reviews what we know about processing of semantic information from speech and iconic gestures in spoken languages during comprehension of such composite utterances. Several studies have shown that comprehension of iconic gestures involves brain activations known to be involved in semantic processing of speech: i.e. modulation of the electrophysiological recording component N400, which is sensitive to the ease of semantic integration of a word to previous context, and recruitment of the left-lateralized frontal–posterior temporal network (left inferior frontal gyrus (IFG), medial temporal gyrus (MTG) and superior temporal gyrus/sulcus (STG/S)). Furthermore, we integrate the information coming from both channels recruiting brain areas such as left IFG, posterior superior temporal sulcus (STS)/MTG and even motor cortex. Finally, this integration is flexible: the temporal synchrony between the iconic gesture and the speech segment, as well as the perceived communicative intent of the speaker, modulate the integration process. Whether these findings are special to gestures or are shared with actions or other visual accompaniments to speech (e.g. lips) or other visual symbols such as pictures are discussed, as well as the implications for a multimodal view of language.

scholarly journals Anterior and Posterior Left Inferior Frontal Gyrus Contribute to the Implementation of Grammatical Determiners During Language Production

2020 ◽  
Vol 11 ◽  
Author(s):  
Byurakn Ishkhanyan ◽  
Violaine Michel Lange ◽  
Kasper Boye ◽  
Jesper Mogensen ◽  
Anke Karabanov ◽  
...  
Keyword(s):  
Language Production ◽  
Inferior Frontal Gyrus ◽  
Left Inferior Frontal Gyrus

scholarly journals Neural bases of phonological and semantic processing in early childhood

2019 ◽  
Author(s):  
Avantika Mathur ◽  
Douglas Schultz ◽  
Yingying Wang
Keyword(s):  
Early Childhood ◽  
Phonological Processing ◽  
Reading Ability ◽  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Early Period ◽  
Semantic Knowledge ◽  
Typically Developing ◽  
Typically Developing Children ◽  
Neural Bases

AbstractDuring the early period of reading development, children gain phonological (letter-to-sound mapping) and semantic knowledge (storage and retrieval of word meaning). Their reading ability changes rapidly, accompanied by their learning-induced brain plasticity as they learn to read. This study aims to identify the specialization of phonological and semantic processing in early childhood using a combination of univariate and multivariate pattern analysis. Nineteen typically developing children between the age of five to seven performed visual word-level phonological (rhyming) and semantic (related meaning) judgment tasks during functional magnetic resonance imaging (fMRI) scans. Our multivariate analysis showed that young children with good reading ability have already recruited the left hemispheric regions in the brain for phonological processing, including the inferior frontal gyrus (IFG), superior and middle temporal gyrus, and fusiform gyrus. Additionally, our multivariate results suggested that the sub-regions of the left IFG were specialized for different tasks. Our results suggest the left lateralization of fronto-temporal regions for phonological processing and bilateral activations of parietal regions for semantic processing during early childhood. Our findings indicate that the neural bases of reading have already begun to be shaped in early childhood for typically developing children, which can be used as a control baseline for comparison of children at-risk for reading difficulties.

scholarly journals Functional MRI of native and non-native speech production in sequential German-English bilinguals

2021 ◽  
Author(s):  
Miriam Treutler ◽  
Peter Sörös
Keyword(s):  
Language Production ◽  
Native Speakers ◽  
Inferior Frontal Gyrus ◽  
Neural Correlates ◽  
Left Inferior Frontal Gyrus ◽  
Non Invasive ◽  
English Vowels ◽  
Native Speech ◽  
Bilingualism And Multilingualism ◽  
Increased Activity

AbstractBilingualism and multilingualism are highly prevalent. Non-invasive brain imaging has been used to study the neural correlates of native (L1) and non-native (L2) speech and language production, mainly on the lexical and syntactic level. Here, we acquired continuous fast event-related FMRI during visually cued overt production of exclusively German and English vowels and syllables. We analyzed data from 13 university students, native speakers of German and sequential English bilinguals. The production of non-native English sounds was associated with increased activity of the left primary sensori-motor cortex, bilateral cerebellar hemispheres (lobule VI), left inferior frontal gyrus, and left anterior insula compared to native German sounds. The contrast German > English sounds was not statistically significant. Our results emphasize that the production of non-native speech requires additional neural resources already on a basic phonological level in sequential bilinguals.

scholarly journals Reading skill correlates in frontal cortex during semantic and phonological processing

2021 ◽  
Author(s):  
Chris Brozdowski ◽  
James R. Booth
Keyword(s):  
Frontal Cortex ◽  
Phonological Processing ◽  
Semantic Processing ◽  
Right Hemisphere ◽  
Inferior Frontal Gyrus ◽  
Reading Skill ◽  
Judgment Task ◽  
Auditory Modality ◽  
Connectionist Model ◽  
Compensatory Mechanisms

Previous studies have generally shown that reading skill is related to a left hemisphere network involving temporal, parietal, or frontal components. A limitation of many of these studies, however, is the neuroimaging of a single reading task, so we know less about how skill modulates the engagement of reading network during various reading tasks. Within the connectionist model, reading engages both phonological and semantic processing regardless of whether it is for pronunciation or meaning. Both target [i.e., ortho-phonological (OP) or ortho-semantic (OS) ] and non-target [i.e., ortho-phono-semantic (OPS) or ortho-sem-phonological (OSP)] paths are likely simultaneously involved in reading. However, readers may vary in their division of labor across target and non-target paths as a function of task and reading skill. Therefore, the goal of the current study was to examine how skill modulates the neural mechanism of reading depending on the task. Children (aged 8 to 15) were given two reading tasks, namely, a rhyming judgment task tapping into orthographic-to-phonological mapping and a meaning judgment task tapping into orthographic-to-semantic mapping. Brain activation during these two reading tasks was then correlated with reading skill. Consistent with previous research showing functional separation of the dorsal versus ventral left inferior frontal gyrus (IFG), we found that better readers showed greater engagement of the opercularis for the rhyming task, whereas they showed a trend for greater engagement of the triangularis for the meaning task. A novel component of the study was to determine whether these skill related regions identified during the reading tasks were also correlated with activation during parallel rhyming and meaning tasks in the auditory modality. We found that better readers only reliably showed greater engagement of opercularis during auditory phonological processing, but there were trends for overall greater engagement of frontal regions with increasing skill. We did not find evidence for compensatory mechanisms for lower skill readers, either in the left or right hemisphere. Taken together, our study suggests some specificity of the frontal cortex for phonological versus semantic processing during reading, but that more effective access to posterior representations by the frontal cortex seems to be a general characteristic of better readers

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