Connectivity Gradient in the Human Left Inferior Frontal Gyrus: Intraoperative Cortico-Cortical Evoked Potential Study

Abstract In the dual-stream model of language processing, the exact connectivity of the ventral stream to the anterior temporal lobe remains elusive. To investigate the connectivity between the inferior frontal gyrus (IFG) and the lateral part of the temporal and parietal lobes, we integrated spatiotemporal profiles of cortico-cortical evoked potentials (CCEPs) recorded intraoperatively in 14 patients who had undergone surgical resection for a brain tumor or epileptic focus. Four-dimensional visualization of the combined CCEP data showed that the pars opercularis (Broca’s area) is connected to the posterior temporal cortices and the supramarginal gyrus, whereas the pars orbitalis is connected to the anterior lateral temporal cortices and angular gyrus. Quantitative topographical analysis of CCEP connectivity confirmed an anterior–posterior gradient of connectivity from IFG stimulus sites to the temporal response sites. Reciprocality analysis indicated that the anterior part of the IFG is bidirectionally connected to the temporal or parietal area. This study shows that each IFG subdivision has different connectivity to the temporal lobe with an anterior–posterior gradient and supports the classical connectivity concept of Dejerine; that is, the frontal lobe is connected to the temporal lobe through the arcuate fasciculus and also a double fan-shaped structure anchored at the limen insulae.

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Connectivity Gradient in the Human Left Inferior Frontal Gyrus: Intraoperative Cortico-Cortical Evoked Potential Study

10.1101/702753 ◽

2019 ◽

Cited By ~ 1

Author(s):

Takuro Nakae ◽

Riki Matsumoto ◽

Takeharu Kunieda ◽

Yoshiki Arakawa ◽

Katsuya Kobayashi ◽

...

Keyword(s):

Temporal Lobe ◽

Language Processing ◽

Anterior Part ◽

Inferior Frontal Gyrus ◽

Angular Gyrus ◽

Epileptic Focus ◽

Lateral Part ◽

Parietal Lobes ◽

Pars Opercularis ◽

Anterior Posterior

AbstractIn the dual-stream model of language processing, the exact connectivity of the ventral stream to the anterior temporal lobe remains elusive. To investigate the connectivity among the inferior frontal gyrus (IFG) and the lateral part of the temporal and parietal lobes, we integrated spatiotemporal profiles of cortico-cortical evoked potentials (CCEPs) recorded intraoperatively from 14 patients who had had resective surgeries for brain tumor or epileptic focus. The 4D visualization of the combined CCEP data showed that the pars opercularis (Broca’s area) connected to the posterior temporal cortices and the supramarginal gyrus, while the pars orbitalis connected to the anterior lateral temporal cortices and the angular gyrus. Quantitative topographical analysis of CCEP connectivity confirmed an anterior-posterior gradient of connectivity from IFG stimulus sites to the temporal response sites. Reciprocality analysis indicated that the anterior part of the IFG is bi-directionally connected to the temporal or parietal area. The present study revealed that each IFG subdivision has a different connectivity to the temporal lobe with an anterior-posterior gradient and supports the classical connectivity concept of Dejerine that the frontal lobe is connected to the temporal lobe through the arcuate fasciculus and also a double-fan-shaped structure, anchored at the limen insulae.

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

Journal of Neurosurgery ◽

10.3171/2012.7.jns12404 ◽

2012 ◽

Vol 117 (5) ◽

pp. 844-850 ◽

Cited By ~ 26

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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The angular gyrus model of consciousness

10.7287/peerj.preprints.22v2 ◽

2013 ◽

Author(s):

Graeme E Smith

Keyword(s):

White Matter ◽

Temporal Lobe ◽

Medial Temporal Lobe ◽

Declarative Memory ◽

Angular Gyrus ◽

Memory Model ◽

White Matter Tracts ◽

Parietal Lobes ◽

Intersection Area ◽

The Brain

The Angular Gyrus sits at the point where the Temporal and Parietal Lobes join. It is a point where integrative processes link together the Where and What pathways through the brain and link them to time. It is also the most likely location for at least two centers of consciousness. In this article the location is discussed and it's potential for a model of consciousness that replaces the Declarative Memory Model of Consciousness previously put forward. It's main benefit over the Declarative Memory Model of Consciousness is that it allows for the preservation of consciousness despite the loss of declarative memory in the cases of Medial Temporal Lobe injury/disease. However Connectome studies might support this model in that the TemporoParietal Fiber Intersection Area provides 7 different white matter tracts that intersect in this area.

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Connected Speech Deficit as an Early Hallmark of CSF-defined Alzheimer’s Disease and Correlation with Cerebral Hypoperfusion Pattern

Current Alzheimer Research ◽

10.2174/1567205016666190506141733 ◽

2019 ◽

Vol 16 (6) ◽

pp. 483-494 ◽

Cited By ~ 1

Author(s):

Giulia Mazzon ◽

Miloš Ajčević ◽

Tatiana Cattaruzza ◽

Alina Menichelli ◽

Michele Guerriero ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Discourse Analysis ◽

Language Processing ◽

Anterior Part ◽

Inferior Frontal Gyrus ◽

Cerebral Hypoperfusion ◽

Global Coherence ◽

Prodromal Alzheimer’S Disease ◽

Mci Due To Ad

Background: Diagnosis of prodromal Alzheimer's disease (AD) still represents a hot topic and there is a growing interest for the detection of early and non-invasive biomarkers. Although progressive episodic memory impairment is the typical predominant feature of AD, communicative difficulties can be already present at the early stages of the disease. Objective: This study investigated the narrative discourse production deficit as a hallmark of CSFdefined prodromal AD and its correlation with cerebral hypoperfusion pattern. Method: Narrative assessment with a multilevel procedure for discourse analysis was conducted on 28 subjects with Mild Cognitive Impairment (15 MCI due to AD; 13 MCI non-AD) and 28 healthy controls. The diagnostic workup included CSF AD biomarkers. Cerebral hypoperfusion pattern was identified by SPECT image processing. Results: The results showed that the discourse analysis of global coherence and lexical informativeness indexes allowed to identify MCI due to AD from MCI non-AD and healthy subjects. These findings allow to hypothesize that the loss of narrative efficacy could be a possible early clinical hallmark of Alzheimer’s disease. Furthermore, a significant correlation of global coherence and lexical informativeness reduction with the SPECT hypoperfusion was found in the dorsal aspect of the anterior part of the left inferior frontal gyrus, supporting the hypothesis that this area has a significant role in communicative efficacy, and in particular, in semantic selection executive control. Conclusion: This study contributes to the understanding of the neural networks for language processing and their involvement in prodromal Alzheimer's disease. It also suggests an easy and sensitive tool for clinical practice that can help identifying individuals with prodromal Alzheimer’s disease.

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High-level language processing regions are not engaged in action observation or imitation

Journal of Neurophysiology ◽

10.1152/jn.00222.2018 ◽

2018 ◽

Vol 120 (5) ◽

pp. 2555-2570 ◽

Cited By ~ 10

Author(s):

Brianna L. Pritchett ◽

Caitlyn Hoeflin ◽

Kami Koldewyn ◽

Eyal Dechter ◽

Evelina Fedorenko

Keyword(s):

Language Processing ◽

Language Comprehension ◽

Music Perception ◽

Action Observation ◽

Inferior Frontal Gyrus ◽

Brain Regions ◽

Angular Gyrus ◽

High Level Language ◽

Left Frontal Lobe ◽

High Level

A set of left frontal, temporal, and parietal brain regions respond robustly during language comprehension and production (e.g., Fedorenko E, Hsieh PJ, Nieto-Castañón A, Whitfield-Gabrieli S, Kanwisher N. J Neurophysiol 104: 1177–1194, 2010; Menenti L, Gierhan SM, Segaert K, Hagoort P. Psychol Sci 22: 1173–1182, 2011). These regions have been further shown to be selective for language relative to other cognitive processes, including arithmetic, aspects of executive function, and music perception (e.g., Fedorenko E, Behr MK, Kanwisher N. Proc Natl Acad Sci USA 108: 16428–16433, 2011; Monti MM, Osherson DN. Brain Res 1428: 33–42, 2012). However, one claim about overlap between language and nonlinguistic cognition remains prominent. In particular, some have argued that language processing shares computational demands with action observation and/or execution (e.g., Rizzolatti G, Arbib MA. Trends Neurosci 21: 188–194, 1998; Koechlin E, Jubault T. Neuron 50: 963–974, 2006; Tettamanti M, Weniger D. Cortex 42: 491–494, 2006). However, the evidence for these claims is indirect, based on observing activation for language and action tasks within the same broad anatomical areas (e.g., on the lateral surface of the left frontal lobe). To test whether language indeed shares machinery with action observation/execution, we examined the responses of language brain regions, defined functionally in each individual participant (Fedorenko E, Hsieh PJ, Nieto-Castañón A, Whitfield-Gabrieli S, Kanwisher N. J Neurophysiol 104: 1177–1194, 2010) to action observation ( experiments 1, 2, and 3a) and action imitation ( experiment 3b). With the exception of the language region in the angular gyrus, all language regions, including those in the inferior frontal gyrus (within “Broca’s area”), showed little or no response during action observation/imitation. These results add to the growing body of literature suggesting that high-level language regions are highly selective for language processing (see Fedorenko E, Varley R. Ann NY Acad Sci 1369: 132–153, 2016 for a review). NEW & NOTEWORTHY Many have argued for overlap in the machinery used to interpret language and others’ actions, either because action observation was a precursor to linguistic communication or because both require interpreting hierarchically-structured stimuli. However, existing evidence is indirect, relying on group analyses or reverse inference. We examined responses to action observation in language regions defined functionally in individual participants and found no response. Thus language comprehension and action observation recruit distinct circuits in the modern brain.

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Indirect White Matter Pathways Are Associated With Treated Naming Improvement in Aphasia

Neurorehabilitation and Neural Repair ◽

10.1177/1545968321999052 ◽

2021 ◽

pp. 154596832199905

Author(s):

Janina Wilmskoetter ◽

Julius Fridriksson ◽

Alexandra Basilakos ◽

Lorelei Phillip Johnson ◽

Barbara Marebwa ◽

...

Keyword(s):

White Matter ◽

Treatment Outcomes ◽

Inferior Frontal Gyrus ◽

Brain Regions ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Middle Temporal ◽

Pars Opercularis ◽

Left Hemisphere Stroke ◽

Linear Regressions

Background White matter disconnection of language-specific brain regions associates with worse aphasia recovery. Despite a loss of direct connections, many stroke survivors may maintain indirect connections between brain regions. Objective To determine (1) whether preserved direct connections between language-specific brain regions relate to better poststroke naming treatment outcomes compared to no direct connections and (2) whether for individuals with a loss of direct connections, preserved indirect connections are associated with better treatment outcomes compared to individuals with no connections. Methods We computed structural whole-brain connectomes from 69 individuals with chronic left-hemisphere stroke and aphasia who completed a 3-week-long language treatment that was supplemented by either anodal transcranial direct current stimulation (A-tDCS) or sham stimulation (S-tDCS). We determined differences in naming improvement between individuals with direct, indirect, and no connections using 1-way analyses of covariance and multivariable linear regressions. Results Independently of tDCS modality, direct or indirect connections between the inferior frontal gyrus pars opercularis and angular gyrus were both associated with a greater increase in correct naming compared to no connections ( P = .027 and P = .039, respectively). Participants with direct connections between the inferior frontal gyrus pars opercularis and middle temporal gyrus who received S-tDCS and participants with indirect connections who received A-tDCS significantly improved in naming accuracy. Conclusions Poststroke preservation of indirect white matter connections is associated with better treated naming improvement in aphasia even when direct connections are damaged. This mechanistic information can be used to stratify and predict treated naming recovery in individuals with aphasia.

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Differential contributions of left-hemispheric language regions to basic semantic composition

Brain Structure and Function ◽

10.1007/s00429-020-02196-2 ◽

2021 ◽

Vol 226 (2) ◽

pp. 501-518

Author(s):

Astrid Graessner ◽

Emiliano Zaccarella ◽

Gesa Hartwigsen

Keyword(s):

Semantic Network ◽

Anterior Part ◽

Inferior Frontal Gyrus ◽

Angular Gyrus ◽

Functional Coupling ◽

Conceptual Combination ◽

Lexical Information ◽

Form Complex ◽

Semantic Composition ◽

Basic Semantic

AbstractSemantic composition, the ability to combine single words to form complex meanings, is a core feature of human language. Despite growing interest in the basis of semantic composition, the neural correlates and the interaction of regions within this network remain a matter of debate. We designed a well-controlled two-word fMRI paradigm in which phrases only differed along the semantic dimension while keeping syntactic information alike. Healthy participants listened to meaningful (“fresh apple”), anomalous (“awake apple”) and pseudoword phrases (“awake gufel”) while performing an implicit and an explicit semantic task. We identified neural signatures for distinct processes during basic semantic composition. When lexical information is kept constant across conditions and the evaluation of phrasal plausibility is examined (meaningful vs. anomalous phrases), a small set of mostly left-hemispheric semantic regions, including the anterior part of the left angular gyrus, is found active. Conversely, when the load of lexical information—independently of phrasal plausibility—is varied (meaningful or anomalous vs. pseudoword phrases), conceptual combination involves a wide-spread left-hemispheric network comprising executive semantic control regions and general conceptual representation regions. Within this network, the functional coupling between the left anterior inferior frontal gyrus, the bilateral pre-supplementary motor area and the posterior angular gyrus specifically increases for meaningful phrases relative to pseudoword phrases. Stronger effects in the explicit task further suggest task-dependent neural recruitment. Overall, we provide a separation between distinct nodes of the semantic network, whose functional contributions depend on the type of compositional process under analysis.

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From letters to composed concepts: A magnetoencephalography study of reading

10.1101/2020.12.07.414656 ◽

2020 ◽

Author(s):

Graham Flick ◽

Osama Abdullah ◽

Liina Pylkkänen

Keyword(s):

Temporal Lobe ◽

Language Processing ◽

Lexical Processing ◽

Temporal Cortex ◽

Noun Phrases ◽

Angular Gyrus ◽

Word Meanings ◽

Word Combination ◽

Thematic Relations ◽

Source Signal

ABSTRACTLanguage comprehension requires the recognition of individual words and the combination of their meanings to yield complex concepts or interpretations. Rather than simple concatenation, this combinatory process often requires the insertion of unstated semantic material between words, based on thematic or feature knowledge of the concepts. For example, the phrase horse barn is not interpreted as a blend of a horse and a barn, but specifically a barn in which horses are kept. Mounting evidence suggests two cortical semantic hubs, in left temporoparietal and anterior temporal cortex, underpin thematic and feature concept knowledge, but much remains unclear about how these putative hubs contribute to combinatory language processing. Using magnetoencephalography, we contrasted source-localized responses to modifier-noun phrases involving thematic relations vs. feature modifications, while also examining how lower-level orthographic processing fed into responses supporting word combination. Twenty-eight participants completed three procedures examining responses to letter-strings, adjective-noun phrases, and noun-noun combinations that varied the semantic relations between words. We found that while color + noun phrases engaged the left anterior temporal lobe (150-300 ms after phrasal head), posterior temporal lobe (150-300 ms), and angular gyrus (300-450 ms), only left posterior temporal lobe responses were sensitive to implicit thematic relations between composing nouns (150-300 ms). We additionally identified a left temporo-occipital progression from orthographic to lexical processing, feeding into ventral anterior areas engaged in the combination of word meanings. Finally, by examining source signal leakage, we characterized the degree to which these responses could be distinguished from one another, using linear source estimation.

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