scholarly journals Functional Activation and Connectivity of the Left Inferior Frontal Gyrus during Lexical and Phonological Retrieval

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1655
Author(s):  
Miguel Ángel Rivas-Fernández ◽  
Benxamín Varela-López ◽  
Susana Cid-Fernández ◽  
Santiago Galdo-Álvarez
Keyword(s):  
Speech Production ◽  
Cognitive Processing ◽  
Inferior Frontal Gyrus ◽  
Naming Task ◽  
Phonological Information ◽  
Cortical Networks ◽  
Left Inferior Frontal Gyrus ◽  
Neural Information ◽  
Pars Opercularis ◽  
Phonological Retrieval

Being language a paradigm of structural and functional asymmetry in cognitive processing, the left Inferior Frontal Gyrus has been consistently related to speech production. In fact, it has been considered a key node in cortical networks responsible for different components of naming. However, isolating these components (e.g., lexical, syntactic, and phonological retrieval) in neuroimaging studies is difficult due to the use of different baselines and tasks. In the present study, functional activation and connectivity of the left inferior frontal gyrus was explored using functional magnetic resonance imaging. Participants performed a covert naming task (pressing a button based on a phonological characteristic). Two conditions were compared: drawings of objects and single letters (baseline condition). Differences in activation and functional connectivity were obtained for objects and letters in different areas of the left Inferior Frontal Gyrus. The pars triangularis was involved in the retrieval of lexical-phonological information, showing a pattern of connectivity with temporal areas in the search for the name of objects and with perisylvanian areas for letters. Selection of phonological information seems to involve the pars opercularis both to letters and objects but recruiting supramarginal and superior temporal areas to letters, probably related to orthographic-phonological conversion. The results support the notion of the left Inferior Frontal Gyrus as a buffer forwarding neural information across cortical networks responsible for different components of speech production.

scholarly journals fMRI Evidence for Dual Routes to the Mental Lexicon in Visual Word Recognition

2002 ◽  
Vol 14 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Christian J. Fiebach ◽  
Angela D. Friederici ◽  
Karsten Müller ◽  
D. Yves von Cramon
Keyword(s):  
Word Processing ◽  
Inferior Frontal Gyrus ◽  
Low Frequency ◽  
Brain Regions ◽  
Visual Word ◽  
Middle Temporal Gyrus ◽  
Lexical Selection ◽  
Left Inferior Frontal Gyrus ◽  
Pars Opercularis ◽  
Left Middle Temporal Gyrus

Event-related fMRI was used to investigate lexical decisions to words of high and low frequency of occurrence and to pseudowords. The results obtained strongly support dual-route models of visual word processing. By contrasting words with pseudowords, bilateral occipito-temporal brain areas and posterior left middle temporal gyrus (MTG) were identified as contributing to the successful mapping of orthographic percepts onto visual word form representations. Low-frequency words and pseudowords elicited greater activations than high-frequency words in the superior pars opercularis [Brodmann's area (BA) 44] of the left inferior frontal gyrus (IFG), in the anterior insula, and in the thalamus and caudate nucleus. As processing of these stimuli during lexical search is known to rely on phonological information, it is concluded that these brain regions are involved in grapheme-to-phoneme conversion. Activation in the pars triangularis (BA 45) of the left IFG was observed only for low-frequency words. It is proposed that this region is involved in processes of lexical selection.

scholarly journals The Neuroanatomy of Speech Sequencing at the Syllable Level

2018 ◽  
Author(s):  
Feng Rong ◽  
A. Lisette Isenberg ◽  
Erica Sun ◽  
Gregory Hickok
Keyword(s):  
Speech Production ◽  
Functional Mri ◽  
Parietal Lobe ◽  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Neural Substrates ◽  
Brain Regions ◽  
Sequence Production ◽  
Left Posterior ◽  
Pars Opercularis

Correctly ordering a sequence of speech sounds is a crucial aspect of speech production. Although studies have yielded a rich body of data on the neural substrates of visuomotor sequencing and sequence learning, research on brain regions and their functions involving speech sequence production hasn’t attracted much attention until recently. Previous functional MRI studies manipulating the complexity of sequences at the phonemic, syllabic, and suprasyllabic levels have revealed a network of motor-related cortical and sub-cortical speech regions. In this study, we directly compared human brain activity measured with functional MRI during processing of a sequence of syllables compared with the same syllables processed individually. Among a network of regions independently identified as being part of the sensorimotor circuits for speech production, only the left posterior inferior frontal gyrus (pars opercularis, lIFG), the supplementary motor area (SMA), and the left inferior parietal lobe (lIPL) responded more during the production of syllable sequences compared to producing the same syllables articulated one at a time.

scholarly journals The Contribution of the Left Inferior Frontal Gyrus in Affective Processing of Social Groups

2018 ◽  
Author(s):  
Tiziano Suran ◽  
Raffaella I Rumiati ◽  
Luca Piretti
Keyword(s):  
Inferior Frontal Gyrus ◽  
Social Groups ◽  
Control Site ◽  
Affective Processing ◽  
Social Stimuli ◽  
Left Inferior Frontal Gyrus ◽  
Negative Valence ◽  
Semantic Priming Effect ◽  
Pars Opercularis ◽  
Stimulation Of

We investigated the contribution of the pars opercularis of the left inferior frontal gyrus (LIFGop) in representing knowledge about social groups. We asked healthy individuals to categorize words preceded by semantically congruent or incongruent primes while stimulating the LIFGop. Previous studies showing an involvement of the LIFGop both in processing social stimuli and negative valence words led us to predict that its stimulation would affect responses to negative social category words. Compared to the Vertex as control site, the stimulation of the LIFGop increased the speed of categorization of negative social groups, and disrupted the semantic priming effect for negative words overall. Within the framework of recent theories of semantic memory, we argue that the present results provide initial evidence of the representation of social groups being characterized by affective properties, whose processing is supported by the LIFGop.

Motor theory modulated by task load: strategies of phonological processing in frontal aphasia revealed by tDCS over the LIFG

2019 ◽  
Author(s):  
Lílian Rodrigues de Almeida ◽  
Paul A. Pope ◽  
Peter Hansen
Keyword(s):  
Speech Perception ◽  
Speech Production ◽  
Phonological Processing ◽  
Inferior Frontal Gyrus ◽  
Dorsal Stream ◽  
Superior Temporal Gyrus ◽  
Motor Theory ◽  
Task Load ◽  
Cathodal Tdcs ◽  
The Individual

In our previous studies we supported the claim that the motor theory is modulated by task load. Motoric participation in phonological processing increases from speech perception to speech production, with the endpoints of the dorsal stream having changing and complementary weightings for processing: the left inferior frontal gyrus (LIFG) being increasingly relevant and the left superior temporal gyrus (LSTG) being decreasingly relevant. Our previous results for neurostimulation of the LIFG support this model. In this study we investigated whether our claim that the motor theory is modulated by task load holds in (frontal) aphasia. Person(s) with aphasia (PWA) after stroke typically have damage on brain areas responsible for phonological processing. They may present variable patterns of recovery and, consequently, variable strategies of phonological processing. Here these strategies were investigated in two PWA with simultaneous fMRI and tDCS of the LIFG during speech perception and speech production tasks. Anodal tDCS excitation and cathodal tDCS inhibition should increase with the relevance of the target for the task. Cathodal tDCS over a target of low relevance could also induce compensation by the remaining nodes. Responses of PWA to tDCS would further depend on their pattern of recovery. Responses would depend on the responsiveness of the perilesional area, and could be weaker than in controls due to an overall hypoactivation of the cortex. Results suggest that the analysis of motor codes for articulation during phonological processing remains in frontal aphasia and that tDCS is a promising diagnostic tool to investigate the individual processing strategies.

scholarly journals Syntactic Complexity and Frequency in the Neurocognitive Language System

2017 ◽  
Vol 29 (9) ◽  
pp. 1605-1620 ◽  
Author(s):  
Yun-Hsuan Yang ◽  
William D. Marslen-Wilson ◽  
Mirjana Bozic
Keyword(s):  
Language Comprehension ◽  
Multivariate Analyses ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Frequency Effect ◽  
Syntactic Complexity ◽  
Left Inferior Frontal Gyrus ◽  
Fmri Study ◽  
Key Factor ◽  
Frequent Items

Prominent neurobiological models of language follow the widely accepted assumption that language comprehension requires two principal mechanisms: a lexicon storing the sound-to-meaning mapping of words, primarily involving bilateral temporal regions, and a combinatorial processor for syntactically structured items, such as phrases and sentences, localized in a left-lateralized network linking left inferior frontal gyrus (LIFG) and posterior temporal areas. However, recent research showing that the processing of simple phrasal sequences may engage only bilateral temporal areas, together with the claims of distributional approaches to grammar, raise the question of whether frequent phrases are stored alongside individual words in temporal areas. In this fMRI study, we varied the frequency of words and of short and long phrases in English. If frequent phrases are indeed stored, then only less frequent items should generate selective left frontotemporal activation, because memory traces for such items would be weaker or not available in temporal cortex. Complementary univariate and multivariate analyses revealed that, overall, simple words (verbs) and long phrases engaged LIFG and temporal areas, whereas short phrases engaged bilateral temporal areas, suggesting that syntactic complexity is a key factor for LIFG activation. Although we found a robust frequency effect for words in temporal areas, no frequency effects were found for the two phrasal conditions. These findings support the conclusion that long and short phrases are analyzed, respectively, in the left frontal network and in a bilateral temporal network but are not retrieved from memory in the same way as simple words during spoken language comprehension.

Syntactic Dependencies as Memorized Sequences in the Brain

2005 ◽  
Vol 50 (1-4) ◽  
pp. 241-266 ◽  
Author(s):  
Yosef Grodzinsky
Keyword(s):  
Working Memory ◽  
Inferior Frontal Gyrus ◽  
Functional Neuroanatomy ◽  
Left Inferior Frontal Gyrus ◽  
Broca’S Region ◽  
Syntactic Representation ◽  
Syntactic Approach ◽  
Syntactic Relations ◽  
Syntactic Dependencies ◽  
The Brain

AbstractThe prospects of a cognitive neuroscience of syntax are considered with respect to functional neuroanatomy of two seemingly independent systems: Working Memory and syntactic representation and processing. It is proposed that these two systems are more closely related than previously supposed. In particular, it is claimed that a sentence with anaphoric dependencies involves several Working Memories, each entrusted with a different linguistic function. Components of Working Memory reside in the Left Inferior Frontal Gyrus, which is associated with Broca’s region. When lesioned, this area manifests comprehension disruptions in the ability to analyze intra-sentential dependencies, suggesting that Working Memory spans over syntactic computations. The unification of considerations regarding Working Memory with a purely syntactic approach to Broca’s regions leads to the conclusion that mechanisms that compute transformations—and no other syntactic relations—reside in this area.

Foix-Chavany-Marie syndrome caused by a disconnection between the right pars opercularis of the inferior frontal gyrus and the supplementary motor area

2012 ◽  
Vol 117 (5) ◽  
pp. 844-850 ◽  
Author(s):  
Juan Martino ◽  
Enrique Marco de Lucas ◽  
Francisco Javier Ibáñez-Plágaro ◽  
José Manuel Valle-Folgueral ◽  
Alfonso Vázquez-Barquero
Keyword(s):  
Supplementary Motor Area ◽  
Diffusion Tensor ◽  
Anterior Part ◽  
Inferior Frontal Gyrus ◽  
Motor Area ◽  
Lower Limbs ◽  
Rare Type ◽  
Orofacial Movement ◽  
Pars Opercularis ◽  
The Right

Foix-Chavany-Marie syndrome (FCMS) is a rare type of suprabulbar palsy characterized by an automaticvoluntary dissociation of the orofacial musculature. Here, the authors report an original case of FCMS that occurred intraoperatively while resecting the pars opercularis of the inferior frontal gyrus. This 25-year-old right-handed man with an incidentally diagnosed right frontotemporoinsular tumor underwent surgery using an asleep-awake-asleep technique with direct cortical and subcortical electrical stimulation and a transopercular approach to the insula. While resecting the anterior part of the pars opercularis the patient suffered sudden anarthria and bilateral facial weakness. He was unable to speak or show his teeth on command, but he was able to voluntarily move his upper and lower limbs. This syndrome lasted for 8 days. Postoperative diffusion tensor imaging tractography revealed that connections of the pars opercularis of the right inferior frontal gyrus with the frontal aslant tract (FAT) and arcuate fasciculus (AF) were damaged. This case supplies evidence for localizing the structural substrate of FCMS. It was possible, for the first time in the literature, to accurately correlate the occurrence of FCMS to the resection of connections between the FAT and AF, and the right pars opercularis of the inferior frontal gyrus. The FAT has been recently described, but it may be an important connection to mediate supplementary motor area control of orofacial movement. The present case also contributes to our knowledge of complication avoidance in operculoinsular surgery. A transopercular approach to insuloopercular gliomas can generate FCMS, especially in cases of previous contralateral lesions. The prognosis is favorable, but the patient should be informed of this particular hazard, and the surgeon should anticipate the surgical strategy in case the syndrome occurs intraoperatively in an awake patient.

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