Stimulating the Semantic Network: What Can TMS Tell Us about the Roles of the Posterior Middle Temporal Gyrus and Angular Gyrus?

The authors measure electroencephalograms (EEGs) from a subject looking at line drawings of body parts and recalling their names silently. The equivalent current dipole source localization (ECDL) method is applied to the event related potentials (ERPs): summed EEGs. As the dominant language area of the subject is considered to be in the right hemisphere in the previous research study, ECDs are localized to the right middle temporal gyrus: the angular gyrus. Then ECDs are localized to the right fusiform gyrus, the right middle temporal pole (TEP), and the right inferior temporal white matter (TWM). ECDs are located in the ventral pathway. The areas are related to the integrated process of visual recognition of pictures and the recalling of words. Some of these areas are also related to image recognition and word generation.

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The neurocognitive basis of knowledge about object identity and events: dissociations reflect opposing effects of semantic coherence and control

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0300 ◽

2019 ◽

Vol 375 (1791) ◽

pp. 20190300 ◽

Cited By ~ 4

Author(s):

Elizabeth Jefferies ◽

Hannah Thompson ◽

Piers Cornelissen ◽

Jonathan Smallwood

Keyword(s):

Semantic Processing ◽

Semantic Network ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Control Network ◽

Object Identity ◽

Automatic Retrieval ◽

Semantic Coherence ◽

Opposing Effects ◽

And Control

Semantic memory encompasses knowledge of specific objects and their diverse associations, but the mechanisms that allow us to retrieve aspects of knowledge required for a given task are poorly understood. The dual hub theory suggests that separate semantic stores represent knowledge of (i) taxonomic categories (in the anterior temporal lobes, ATL) and (ii) thematic associations (in angular gyrus, AG or posterior middle temporal gyrus, pMTG). Alternatively, the controlled semantic cognition (CSC) framework suggests that semantic processing emerges from the flexible interaction of heteromodal semantic representations in ATL with a semantic control network, which includes pMTG as well as prefrontal regions. According to this view, ATL supports patterns of coherent auto-associative retrieval, while semantic control sites respond when ongoing conceptual activation needs to be altered to suit the task or context. These theories make different predictions about the nature of functional dissociations within the semantic network. We review evidence for these claims across multiple methods. First, we show ATL is sensitive to the strength of thematic associations as well as taxonomic relations. Next, we document functional dissociations between AG and pMTG: rather than these regions acting as comparable thematic hubs, AG is allied to the default mode network and supports more ‘automatic’ retrieval, while pMTG responds when control demands are high. However, the semantic control network, including pMTG, also shows a greater response to events/actions and verbs, supporting the claims of both theories. We propose that tasks tapping event semantics often require greater shaping of conceptual retrieval than comparison tasks, because these elements of our knowledge are inherently flexible, with relevant features depending on the context. In this way, the CSC account might be able to account for findings that suggest both a process and a content distinction within the semantic network. This article is part of the theme issue ‘Towards mechanistic models of meaning composition’.

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Going beyond Inferior Prefrontal Involvement in Semantic Control: Evidence for the Additional Contribution of Dorsal Angular Gyrus and Posterior Middle Temporal Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00442 ◽

2013 ◽

Vol 25 (11) ◽

pp. 1824-1850 ◽

Cited By ~ 221

Author(s):

Krist A. Noonan ◽

Elizabeth Jefferies ◽

Maya Visser ◽

Matthew A. Lambon Ralph

Keyword(s):

Functional Neuroimaging ◽

Semantic Network ◽

Temporal Cortex ◽

Case Series ◽

Regulatory Control ◽

Angular Gyrus ◽

Additional Contribution ◽

Middle Temporal ◽

Semantic Cognition ◽

Semantic Impairment

Semantic cognition requires a combination of semantic representations and executive control processes to direct activation in a task- and time-appropriate fashion [Jefferies, E., & Lambon Ralph, M. A. Semantic impairment in stroke aphasia versus semantic dementia: A case-series comparison. Brain, 129, 2132–2147, 2006]. We undertook a formal meta-analysis to investigate which regions within the large-scale semantic network are specifically associated with the executive component of semantic cognition. Previous studies have described in detail the role of left ventral pFC in semantic regulation. We examined 53 studies that contrasted semantic tasks with high > low executive requirements to determine whether cortical regions beyond the left pFC show the same response profile to executive semantic demands. Our findings revealed that right pFC, posterior middle temporal gyrus (pMTG) and dorsal angular gyrus (bordering intraparietal sulcus) were also consistently recruited by executively demanding semantic tasks, demonstrating patterns of activation that were highly similar to the left ventral pFC. These regions overlap with the lesions in aphasic patients who exhibit multimodal semantic impairment because of impaired regulatory control (semantic aphasia)—providing important convergence between functional neuroimaging and neuropsychological studies of semantic cognition. Activation in dorsal angular gyrus and left ventral pFC was consistent across all types of executive semantic manipulation, regardless of whether the task was receptive or expressive, whereas pMTG activation was only observed for manipulation of control demands within receptive tasks. Second, we contrasted executively demanding tasks tapping semantics and phonology. Our findings revealed substantial overlap between the two sets of contrasts within left ventral pFC, suggesting this region underpins domain-general control mechanisms. In contrast, we observed relative specialization for semantic control within pMTG as well as the most ventral aspects of left pFC (BA 47), consistent with our proposal of a distributed network underpinning semantic control.

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The Connectivity–Based Parcellation of The Angular Gyrus: Fiber Dissection And MR Tractography Study

10.21203/rs.3.rs-1228692/v1 ◽

2022 ◽

Author(s):

Fatih Yakar ◽

Pınar Çeltikçi ◽

Yücel Doğruel ◽

Emrah Egemen ◽

Abuzer Güngör

Keyword(s):

Anterior Commissure ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Supramarginal Gyrus ◽

Middle Temporal ◽

Fiber Tracts ◽

Human Connectome Project ◽

Cortical Parcellation ◽

Fiber Dissection ◽

First Time

Abstract The angular gyrus (AG) wraps the posterior end of the superior temporal sulcus (STS), so it is considered as a continuation of the superior/middle temporal gyrus and forms the inferior parietal lobule (IPL) with the supramarginal gyrus (SMG). The AG was functionally divided in the literature, but there is no fiber dissection study in this context. This study divided AG into superior (sAG) and inferior (iAG) parts by focusing on STS. Red blue silicone injected eight human cadaveric cerebrums were dissected via the Klingler method focusing on the AG. White matter (WM) tracts identified during dissection were then reconstructed on the Human Connectome Project 1065 individual template for validation. According to this study, superior longitudinal fasciculus (SLF) II and middle longitudinal fasciculus (MdLF) are associated with sAG; the anterior commissure (AC), optic radiation (OR) with iAG; the arcuate fasciculus (AF), inferior frontooccipital fasciculus (IFOF), and tapetum (Tp) with both parts. In cortical parcellation of AG based on STS, sAG and iAG were found to be associated with different fiber tracts. Although it has been shown in previous studies that there are functionally different subunits with AG parcellation, here, for the first time, different functions of the subunits have been revealed with cadaveric dissection and tractography images.

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Automatic and Controlled Semantic Retrieval: TMS Reveals Distinct Contributions of Posterior Middle Temporal Gyrus and Angular Gyrus

Journal of Neuroscience ◽

10.1523/jneurosci.4705-14.2015 ◽

2015 ◽

Vol 35 (46) ◽

pp. 15230-15239 ◽

Cited By ~ 83

Author(s):

J. Davey ◽

P. L. Cornelissen ◽

H. E. Thompson ◽

S. Sonkusare ◽

G. Hallam ◽

...

Keyword(s):

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Semantic Retrieval ◽

Middle Temporal

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Brain Damage Associated with Impaired Sentence Processing in Acute Aphasia

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01478 ◽

2020 ◽

Vol 32 (2) ◽

pp. 256-271 ◽

Cited By ~ 4

Author(s):

Sigfus Kristinsson ◽

Helga Thors ◽

Grigori Yourganov ◽

Sigridur Magnusdottir ◽

Haukur Hjaltason ◽

...

Keyword(s):

Brain Damage ◽

Sentence Processing ◽

Syntactic Processing ◽

Angular Gyrus ◽

Matching Task ◽

Middle Temporal Gyrus ◽

Broca’S Area ◽

Broca's Area ◽

Middle Temporal ◽

Acute Aphasia

Left-hemisphere brain damage commonly affects patients' abilities to produce and comprehend syntactic structures, a condition typically referred to as “agrammatism.” The neural correlates of agrammatism remain disputed in the literature, and distributed areas have been implicated as important predictors of performance, for example, Broca's area, anterior temporal areas, and temporo-parietal areas. We examined the association between damage to specific language-related ROIs and impaired syntactic processing in acute aphasia. We hypothesized that damage to the posterior middle temporal gyrus, and not Broca's area, would predict syntactic processing abilities. One hundred four individuals with acute aphasia (<20 days poststroke) were included in the study. Structural MRI scans were obtained, and all participants completed a 45-item sentence–picture matching task. We performed an ROI-based stepwise regression analyses to examine the relation between cortical brain damage and impaired comprehension of canonical and noncanonical sentences. Damage to the posterior middle temporal gyrus was the strongest predictor for overall task performance and performance on noncanonical sentences. Damage to the angular gyrus was the strongest predictor for performance on canonical sentences, and damage to the posterior superior temporal gyrus predicted noncanonical scores when performance on canonical sentences was included as a cofactor. Overall, our models showed that damage to temporo-parietal and posterior temporal areas was associated with impaired syntactic comprehension. Our results indicate that the temporo-parietal area is crucially implicated in complex syntactic processing, whereas the role of Broca's area may be complementary.

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III. A comparison of the latency periods of the ocular muscles on excitation of the frontal and occipito-temporal regions of the brain

Proceedings of the Royal Society of London ◽

10.1098/rspl.1887.0158 ◽

1888 ◽

Vol 43 (258-265) ◽

pp. 411-412 ◽

Cited By ~ 4

Keyword(s):

Cerebral Cortex ◽

Occipital Lobe ◽

Superior Temporal Gyrus ◽

Frontal Region ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Middle Temporal ◽

Posterior Limb ◽

The Brain

Conjugate deviation of the eyes to the opposite side is produced by excitation of entirely different regions of the cerebral cortex. The parts which when electrically excited produce this movement are: (1) An area in the frontal region of the hemisphere which is included in the motor or psychomotor zone of authors; (2) the superior temporal gyrus; (3) the upper end of the middle temporal gyrus; (4) the posterior limb of the angular gyrus; (5) the whole cortex of the occipital lobe including its mesial and under surfaces; (6) the quadrate lobule.

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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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Distinct Roles for the Cerebellum, Angular Gyrus, and Middle Temporal Gyrus in Action–Feedback Monitoring

Cerebral Cortex ◽

10.1093/cercor/bhy048 ◽

2018 ◽

Vol 29 (4) ◽

pp. 1520-1531 ◽

Cited By ~ 12

Author(s):

Bianca M van Kemenade ◽

B Ezgi Arikan ◽

Kornelius Podranski ◽

Olaf Steinsträter ◽

Tilo Kircher ◽

...

Keyword(s):

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Middle Temporal ◽

Feedback Monitoring

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Speaking in the Brain: The Interaction between Words and Syntax in Sentence Production

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01563 ◽

2020 ◽

Vol 32 (8) ◽

pp. 1466-1483

Author(s):

Atsuko Takashima ◽

Agnieszka Konopka ◽

Antje Meyer ◽

Peter Hagoort ◽

Kirsten Weber

Keyword(s):

Language Production ◽

Inferior Frontal Gyrus ◽

Sentence Production ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Temporal Region ◽

Middle Temporal ◽

Sentence Level ◽

Left Posterior ◽

Language Network

This neuroimaging study investigated the neural infrastructure of sentence-level language production. We compared brain activation patterns, as measured with BOLD-fMRI, during production of sentences that differed in verb argument structures (intransitives, transitives, ditransitives) and the lexical status of the verb (known verbs or pseudoverbs). The experiment consisted of 30 mini-blocks of six sentences each. Each mini-block started with an example for the type of sentence to be produced in that block. On each trial in the mini-blocks, participants were first given the (pseudo-)verb followed by three geometric shapes to serve as verb arguments in the sentences. Production of sentences with known verbs yielded greater activation compared to sentences with pseudoverbs in the core language network of the left inferior frontal gyrus, the left posterior middle temporal gyrus, and a more posterior middle temporal region extending into the angular gyrus, analogous to effects observed in language comprehension. Increasing the number of verb arguments led to greater activation in an overlapping left posterior middle temporal gyrus/angular gyrus area, particularly for known verbs, as well as in the bilateral precuneus. Thus, producing sentences with more complex structures using existing verbs leads to increased activation in the language network, suggesting some reliance on memory retrieval of stored lexical–syntactic information during sentence production. This study thus provides evidence from sentence-level language production in line with functional models of the language network that have so far been mainly based on single-word production, comprehension, and language processing in aphasia.

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