scholarly journals Revealing the neural networks that extract conceptual gestalts from continuously evolving or changing semantic contexts

2019 ◽  
Author(s):  
Francesca M. Branzi ◽  
Gina F. Humphreys ◽  
Paul Hoffman ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Right Hemisphere ◽  
Internal Representation ◽  
Semantic Integration ◽  
Multivariate Techniques ◽  
List Type ◽  
Semantic Cognition ◽  
Narrative Processing ◽  
Time Space ◽  
Context Integration ◽  
Meaningful Stimuli

AbstractReading a book, understanding the news reports or any other behaviour involving the processing of meaningful stimuli requires the semantic system to have two main features: being active during an extended period of time and flexibly adapting the internal representation according to the changing environment. Despite being key features of many everyday tasks, formation and updating of the semantic “gestalt” are still poorly understood. In this fMRI study we used naturalistic stimuli and task manipulations to identify the neural network that forms and updates conceptual gestalts during time-extended integration of meaningful stimuli. Univariate and multivariate techniques allowed at drawing a distinction between networks that are crucial for the formation of a semantic gestalt (meaning integration) and those that instead are important for linking incoming cues about the current context (e.g., time, space cues) into a schema representation. Specifically, we revealed that time-extended formation of the conceptual gestalt was reflected in the neurocomputations of the anterior temporal lobe accompanied by multi-demand areas and hippocampus, with a key role of brain structures in the right hemisphere. This “semantic gestalt network” was strongly recruited when an update of the current semantic representation was required during narrative processing. A distinct fronto-parietal network, instead, was recruited for context integration, independently from the meaning associations between words (semantic coherence). Finally, in contrast with accounts positing that the default-mode-network (DMN) may have a crucial role in semantic cognition, our findings revealed that DMN activity was sensitive to task difficulty, but not to semantic integration. The implications of these findings for neurocognitive models of semantic cognition and the literature on narrative processing are discussed.HighlightsfMRI revealed areas and networks for semantic integration during narrative readingATL has a key role in the formation of the conceptual gestaltIFG, pMTG and dAG reflect the update of the conceptual gestaltLeft AG (Mid-PGp) has a key role in context integration

scholarly journals Semantic integration in reading: engagement of the right hemisphere during discourse processing

Brain ◽  
1999 ◽  
Vol 122 (7) ◽  
pp. 1317-1325 ◽  
Author(s):  
M. St George ◽  
M. Kutas ◽  
A. Martinez ◽  
M. I. Sereno
Keyword(s):  
Right Hemisphere ◽  
Semantic Integration ◽  
Discourse Processing ◽  
Reading Engagement ◽  
The Right

Modulation of neglect hemianesthesia by transcutaneous electrical stimulation

1996 ◽  
Vol 2 (5) ◽  
pp. 452-459 ◽  
Author(s):  
Giuseppe Vallar ◽  
Maria Luisa Rusconi ◽  
Bruno Bernardini
Keyword(s):  
Electrical Stimulation ◽  
Right Hemisphere ◽  
Internal Representation ◽  
Tactile Perception ◽  
The Body ◽  
Transcutaneous Electrical Stimulation ◽  
Neural Basis ◽  
Left Brain ◽  
Right Brain ◽  
Stimulation Of

AbstractThe effects of transcutaneous electrical stimulation on deficits of tactile perception contralateral to a hemispheric lesion were investigated in 10 right brain-damaged patients and in four left brain-damaged patients. The somatosensory deficit recovered, transiently and in part, after stimulation of the side of the neck contralateral to the side of the lesion, in all 10 patients with lesions in the right hemisphere, both with (six cases) and without (four cases) left visuo-spatial hemineglect, and in one left brain-damaged patient with right hemineglect. In three left brain-damaged patients without hemineglect, the treatment had no detectable effects. In one right brain-damaged patient, the stimulation of the side of the neck ipsilateral to the side of the lesion temporarily worsened the somatosensory deficit. These effects of transcutaneous electrical stimulation are similar to those of vestibular stimulation. The suggestion is made that these treatments modulate, through afferent sensory pathways, higher-order spatial representations of the body, which are pathologically distorted toward the side of the lesion. The modulatory effect is direction-specific: the defective internal representation of the contralesional side may be either partly restored, improving the disorder of tactile perception, or further impoverished, worsening the deficit. The possible neural basis of this modulation is discussed. (JINS, 1996, 2, 452–459.)

scholarly journals Neural Mechanisms of Verb Argument Structure Processing in Agrammatic Aphasic and Healthy Age-matched Listeners

2010 ◽  
Vol 22 (9) ◽  
pp. 1993-2011 ◽  
Author(s):  
Cynthia K. Thompson ◽  
Borna Bonakdarpour ◽  
Stephen F. Fix
Keyword(s):  
Sentence Processing ◽  
Argument Structure ◽  
Right Hemisphere ◽  
Semantic Integration ◽  
Neural Mechanisms ◽  
Angular Gyrus ◽  
Decision Task ◽  
Verb Argument Structure ◽  
Verb Processing ◽  
Structure Complexity

Processing of lexical verbs involves automatic access to argument structure entries entailed within the verb's representation. Recent neuroimaging studies with young normal listeners suggest that this involves bilateral posterior peri-sylvian tissue, with graded activation in these regions on the basis of argument structure complexity. The aim of the present study was to examine the neural mechanisms of verb processing using fMRI in older normal volunteers and patients with stroke-induced agrammatic aphasia, a syndrome in which verb, as compared to noun, production often is selectively impaired, but verb comprehension in both on-line and off-line tasks is spared. Fourteen healthy listeners and five age-matched aphasic patients performed a lexical decision task, which examined verb processing by argument structure complexity, namely, one-argument [i.e., intransitive (v1)], two-argument [i.e., transitive (v2)], and three-argument (v3) verbs. Results for the age-matched listeners largely replicated those for younger participants studied by Thompson et al. [Thompson, C. K., Bonakdarpour, B., Fix, S. C., Blumenfeld, H. K., Parrish, T. B., Gitelman, D. R., et al. Neural correlates of verb argument structure processing. Journal of Cognitive Neuroscience, 19, 1753–1767, 2007]: v3 − v1 comparisons showed activation of the angular gyrus in both hemispheres and this same heteromodal region was activated in the left hemisphere in the (v2 + v3) − v1 contrast. Similar results were derived for the agrammatic aphasic patients, however, activation was unilateral (in the right hemisphere for three participants) rather than bilateral, likely because these patients' lesions extended to the left temporo-parietal region. All performed the task with high accuracy and, despite differences in lesion site and extent, they recruited spared tissue in the same regions as healthy subjects. Consistent with psycholinguistic models of sentence processing, these findings indicate that the posterior language network is engaged for processing verb argument structure and is crucial for semantic integration of argument structure information.

scholarly journals High Gamma Cortical Processing of Continuous Speech in Younger and Older Listeners

2019 ◽  
Author(s):  
Joshua P. Kulasingham ◽  
Christian Brodbeck ◽  
Alessandro Presacco ◽  
Stefanie E. Kuchinsky ◽  
Samira Anderson ◽  
...  
Keyword(s):  
Older Adults ◽  
Right Hemisphere ◽  
Acoustic Stimulus ◽  
Auditory Pathway ◽  
List Type ◽  
Continuous Speech ◽  
Speech Stimuli ◽  
Age Related ◽  
Cortical Responses ◽  
High Gamma

AbstractNeural processing along the ascending auditory pathway is often associated with a progressive reduction in characteristic processing rates. For instance, the well-known frequency-following response (FFR) of the auditory midbrain, as measured with electroencephalography (EEG), is dominated by frequencies from ∼100 Hz to several hundred Hz, phase-locking to the acoustic stimulus at those frequencies. In contrast, cortical responses, whether measured by EEG or magnetoencephalography (MEG), are typically characterized by frequencies of a few Hz to a few tens of Hz, time-locking to acoustic envelope features. In this study we investigated a crossover case, cortically generated responses time-locked to continuous speech features at FFR-like rates. Using MEG, we analyzed responses in the high gamma range of 70–200 Hz to continuous speech using neural source-localized reverse correlation and the corresponding temporal response functions (TRFs). Continuous speech stimuli were presented to 40 subjects (17 younger, 23 older adults) with clinically normal hearing and their MEG responses were analyzed in the 70–200 Hz band. Consistent with the relative insensitivity of MEG to many subcortical structures, the spatiotemporal profile of these response components indicated a cortical origin with ∼40 ms peak latency and a right hemisphere bias. TRF analysis was performed using two separate aspects of the speech stimuli: a) the 70–200 Hz carrier of the speech, and b) the 70–200 Hz temporal modulations in the spectral envelope of the speech stimulus. The response was dominantly driven by the envelope modulation, with a much weaker contribution from the carrier. Age-related differences were also analyzed to investigate a reversal previously seen along the ascending auditory pathway, whereby older listeners show weaker midbrain FFR responses than younger listeners, but, paradoxically, have stronger cortical low frequency responses. In contrast to both these earlier results, this study did not find clear age-related differences in high gamma cortical responses to continuous speech. Cortical responses at FFR-like frequencies shared some properties with midbrain responses at the same frequencies and with cortical responses at much lower frequencies.HighlightsCortical MEG responses time-lock at 80–90 Hz to continuous speechResponses primarily driven by high gamma rate fluctuations of the speech envelopeResponse strength and latency are similar for younger and older adults

scholarly journals The Neural Correlates of Semantic Control Revisited

2020 ◽  
Author(s):  
Rebecca L. Jackson
Keyword(s):  
Semantic Network ◽  
Meta Analysis ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Neural Correlates ◽  
Middle Temporal Gyrus ◽  
Control Network ◽  
Temporal Region ◽  
List Type ◽  
Semantic Cognition

AbstractSemantic control, the ability to selectively access and manipulate meaningful information on the basis of context demands, is a critical component of semantic cognition. The precise neural correlates of semantic control are disputed, with particular debate surrounding parietal involvement, the spatial extent of the posterior temporal contribution and network lateralisation. Here semantic control is revisited, utilising improved analysis techniques and a decade of additional data to refine our understanding of the network. A meta-analysis of 876 peaks over 121 contrasts illuminated a left-focused network consisting of inferior frontal gyrus, posterior middle temporal gyrus, posterior inferior temporal gyrus and dorsomedial prefrontal cortex. This extended the temporal region implicated, and found no parietal involvement. Although left-lateralised overall, relative lateralisation varied across the implicated regions. Supporting analyses confirmed the multimodal nature of the semantic control network and situated it within the wider set of regions implicated in semantic cognition.Highlights➢A multimodal semantic control network was delineated with formal meta-analyses➢Semantic control recruits inferior and medial frontal and posterior temporal cortex➢A large extent of posterior temporal cortex was implicated and no parietal regions➢Semantic control is left-lateralised but regions show differential lateralisation➢The semantic control regions were situated in the context of the wider semantic network

scholarly journals Effective Connectivity Study Guiding the Neuromodulation Intervention in Figurative Language Comprehension Using Optical Neuroimaging

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Tania Alexandra Couto ◽  
Shiyang Xu ◽  
Paulo Armada da Silva ◽  
Chenggang Wu ◽  
Karl Neergaard ◽  
...  
Keyword(s):  
Language Comprehension ◽  
Semantic Processing ◽  
Figurative Language ◽  
Right Hemisphere ◽  
Brain Network ◽  
Semantic Integration ◽  
Memory Storage ◽  
Causal Relationships ◽  
Bottom Up ◽  
Figurative Language Comprehension

The current study is aimed at establishing links between brain network examination and neural plasticity studies measured by optical neuroimaging. Sixteen healthy subjects were recruited from the University of Macau to test the Granger Prediction Estimation (GPE) method to investigate brain network connectivity during figurative language comprehension. The method is aimed at mapping significant causal relationships across language brain networks, captured by functional near-infrared spectroscopy measurements (fNIRS): (i) definition of regions of interest (ROIs) based on significant channels extracted from spatial activation maps; (ii) inspection of significant causal relationships in temporal resolution, exploring the experimental task agreement; and (iii) early identification of stronger causal relationships that guide neuromodulation intervention, targeting impaired connectivity pathways. Our results propose top-down mechanisms responsible for perceptive-attention engagement in the left anterior frontal cortex and bottom-up mechanism in the right hemispheres during the semantic integration of figurative language. Moreover, the interhemispheric directional flow suggests a right hemisphere engagement in decoding unfamiliar literal sentences and fine-grained integration guided by the left hemisphere to reduce ambiguity in meaningless words. Finally, bottom-up mechanisms seem activated by logographic-semantic processing in literal meanings and memory storage centres in meaningless comprehension. To sum up, our main findings reveal that the Granger Prediction Estimation (GPE) integrated strategy proposes an effective link between assessment and intervention, capable of enhancing the efficiency of the treatment in language disorders and reducing the neuromodulation side effects.

The Contributes of Cerebellum in Higher Cognitive and Social Behaviour in Childhood

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
F. Dobi ◽  
E. Kabili ◽  
D. Elezi ◽  
E. Sotiri ◽  
G. Xhepa ◽  
...  
Keyword(s):  
Social Organization ◽  
Language Processing ◽  
Developmental Disorders ◽  
Right Hemisphere ◽  
Neurological Diseases ◽  
List Type ◽  
Brain Functions ◽  
Sequential Memory ◽  
Design Fluency ◽  
The Right

Many studies have confirmed the role of the cerebellum in the organization of superior brain functions in adults. Congenital cerebellar alterations are frequently observed in children with neurological diseases. These anatomical alterations are associated with neuropsychological or developmental disorders that often give rise to pictures of mental insufficiency of varying severity with behavioural changes even leading to autism.Aim:To evaluate of cerebellum role in cognitive and social organization also during development.We report 25 children with different kinds of acquired cerebellar lesions (12 with hemispheric astrocytoma, 12 with vermis medulloblastoma, and 1 with hemispheric stroke) who showed different clinical patterns according to the lesion localization. All subject were studied by neurological examination and MRI. Neuropsychological assessment included:•observation of spontaneous behaviour;•Recording of spontaneous language;•Intelligence evaluation (WISC-test);•Language evaluation;•Memory evaluation;•Assessment of frontal lobe functions (categorical memory, sequential memory, language fluency, design fluency, flexibility of reasoning and problem solving).Lesion in the vermis, mainly in the lower lobuli, caused different degrees of behavioural disturbances ranging from irritability to psychosis; lesions in the right hemisphere impaired language processing and symbolic sequencing, categorical memory and executive functions; lesions in the left hemisphere impaired speech prosody, visual sequential memory and design fluency.These data confirm that the connections from the cerebellum to the associative cortical areas are operative very early and that the cerebellum has an essential role in cognitive and social organization also during development.

scholarly journals Feature overlap modulates rapid semantic but not lexical integration of novel associations by means of fast mapping

2019 ◽  
Author(s):  
Ann-Kathrin Zaiser ◽  
Patric Meyer ◽  
Regine Bader
Keyword(s):  
Semantic Integration ◽  
List Type ◽  
Fast Mapping ◽  
Lexical Competition ◽  
Cortical Networks ◽  
Learning Procedure ◽  
Item Level ◽  
Feature Overlap ◽  
Novel Associations ◽  
Shed Light

AbstractThere is evidence that rapid integration of novel associations into cortical networks is possible if associations are acquired through a learning procedure called fast mapping (FM). FM requires precise visual discrimination of sometimes highly similar pictures of a previously unknown and a known item, and linking an unfamiliar label to the unknown item. In order to shed light on the mechanisms underlying learning through FM, we manipulated feature overlap between the two items as potential modulating factor. In Experiment 1, we found that labels of the unknown items generally evoked instantaneous lexical competition when encoded through FM, indicating rapid integration into lexical networks. In Experiment 2, we observed semantic priming immediately after FM encoding but only if the items shared many features. This indicates that whereas feature overlap leaves item-level lexical integration unaffected, it might mediate semantic integration of arbitrary picture-label associations, which could explain contradictory findings in the literature.HighlightsWe examined cortical integration of associations using implicit memory measures.Fast mapping enables immediate integration of associations into cortical networks.Semantic integration requires the discrimination between items sharing many features.Item-level lexical integration is unaffected by feature overlap.

Psychosis Related to TBI

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
O. Euba ◽  
E. Zallo ◽  
N. Sanchez ◽  
M. Torreblanca ◽  
A. Arroita ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Mental Disorders ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Systemic Review ◽  
Psychotic Symptoms ◽  
List Type ◽  
Type Number ◽  
Legal Implications ◽  
Wide Range

Aims:Traumatic brain injury (TBI) cause a wide range of serious consequences, including psychiatric disorders. Psychosis although uncommon is a very serious consequences with important functional, therapeutical and legal implications.Methods:Our work is based on a systemic review of the articles published related to TBI and psychosis.Results and conlusions:Three different features about TBI and their relation with the development of psychotic symptoms are analyzed.1.Severity: Serious TBI are more related to psychosis. Moderate and minor TBI can develop mental disorders is there is a previous neurological lesions.2.Localization: Temporal lobe appears affected in most of the patients.3.Lateralization: Left hemisphere is usually affected.Left hemisphere traumas appear to cause schizophrenia-like psychosis. Right hemisphere traumas are related to delirious and special types of psychosis.

scholarly journals Lateral Asymmetry in Weekly Reproducibility of Resting State Amygdala Functional Connectivity

2018 ◽  
Author(s):  
Alina Tetereva ◽  
Vladislav Balaev ◽  
Sergey Kartashov ◽  
Vadim Ushakov ◽  
Alexey Ivanitsky ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Default Mode Network ◽  
Resting State ◽  
Right Hemisphere ◽  
List Type ◽  
Post Traumatic Stress ◽  
Lateral Asymmetry ◽  
Default Mode ◽  
Functional Connections ◽  
The Right

AbstractAbnormal functional connectivity of the amygdala with several other brain regions has been observed in patients with higher anxiety or post-traumatic stress disorder, both in a resting state and threatening conditions. However, findings on the specific connections of the amygdala might be varied due to temporal and individual fluctuations in the resting state functional connectivity (rsFC) of the amygdala and its lateral asymmetry, as well as possible variability in anxiety among healthy subjects. We studied reproducibility of rsFC data for the right and left amygdala, obtained by functional magnetic resonance imaging twice in a one-week interval in 20 healthy volunteers with low to moderate anxiety. We found resting-state amygdala network, which included not only areas involved in the emotion circuit, but regions of the default mode network (DMN) associated with memory and other brain areas involved in motor inhibition and emotion suppression. The amygdala network was stable in time and within subjects, but between-session reproducibility was asymmetrical for the right and left amygdala rsFC. The right amygdala had more significant connections with DMN regions and the right ventrolateral prefrontal cortex. The rsFC values of the right amygdala were more sustained across the week than the left amygdala rsFC. Our results support a hypothesis of functional lateralization of the amygdala. The left amygdala is more responsible for the conscious processing of threats, which may produce more variable rsFC; the right amygdala rsFC is more stable due to its greater engagement in continuous automatic evaluation of stimuli.HighlightsAmygdala resting state network included areas of emotion circuit and motor controlDuring rest amygdala was functionally connected with areas of default mode networkFunctional connectivity of the right amygdala was more sustained across the weekFunctional connections of amygdala network were more stable in the right hemisphere

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