scholarly journals Multimodal Comprehension in Left Hemisphere Stroke Patients

2020 ◽  
Author(s):  
Gabriella Vigliocco ◽  
Anna Krason ◽  
Harrison Stoll ◽  
Alessandro Monti ◽  
Laurel Buxbaum
Keyword(s):  
Gesture Recognition ◽  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Video Clip ◽  
Temporal Cortex ◽  
Support Vector ◽  
Speech Task ◽  
Lexical Semantic ◽  
Lesion Symptom Mapping ◽  
The Brain

Hand gestures, imagistically related to the content of speech, are ubiquitous in face-to-face communication. In the first study with people with aphasia (PWA) investigating speech-gesture processing in the brain using lesion-symptom mapping, we investigated the brain regions as well as the lexical-semantic and gesture recognition abilities associated with benefits and costs of multimodal speech-gesture input. Twenty-nine PWA and 16 matched controls were shown a picture of an object/action and then a video-clip of a speaker producing speech-gesture pairs (congruent/incongruent) or only speaking or gesturing. Their task was to indicate, in different blocks, whether the picture and the word matched (Speech task), or whether the picture and the gesture matched (Gesture task). Multivariate lesion analysis with Support Vector Regression Lesion Symptom Mapping (SVR-LSM) showed that benefit for congruent speech-gesture was associated with 1) lesioned voxels in anterior fronto-temporal regions including inferior frontal gyrus (IFG), and sparing of posterior temporal cortex and lateral temporal-occipital regions (pTC/LTO) for the Speech task, and 2) conversely, lesions to pTC/LTO and sparing of anterior regions for the Gesture task. The two tasks did not share overlapping voxels. Costs from incongruent speech-gesture pairings were associated with lesioned voxels in these same anterior (for the Speech task) and posterior (for the Gesture task) regions, but crucially, also shared voxels in superior and middle temporal gyri, including the anterior temporal lobe. These results suggest that IFG and pTC/LTO contribute to extracting semantic information from speech or gesture respectively; however, they are not causally involved in integrating information from the two modalities. In contrast, regions in anterior STG/MTG are associated with performance in both tasks and may thus be critical to speech-gesture integration. These conclusions are further supported by associations between benefits/costs specific to each task and performance in tests assessing lexical-semantic processing and gesture recognition.

scholarly journals Decoding social knowledge in the human brain

2020 ◽  
Author(s):  
Daniel Alcalá-López ◽  
David Soto
Keyword(s):  
Temporal Lobe ◽  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
A Priori ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Social Knowledge ◽  
Support Vector ◽  
Meta Analyses ◽  
The Brain

AbstractThe present functional MRI study addressed how the brain maps different aspects of social information. We focused on two key dimensions of social knowledge: affect and likableness. Thirty participants were presented with audio definitions, half referring to affective (e.g. empathetic) and half to non-affective concepts (e.g. intelligent). Orthogonally, half of the concepts were highly likable (e.g. sincere) and half were socially undesirable (e.g. liar). We used a support vector machine to delineate how both concept dimensions are represented in a set of 9 a priori brain regions defined from previous meta-analyses on semantic and social cognition. We show that average decoding in semantic regions (e.g. lateral temporal lobe, inferior frontal gyrus, and precuneus) outperformed social ROIs (e.g. insula and anterior cingulate), with the lateral temporal lobe containing the highest amount of information about the affect and likableness of social concepts. We also found that the insula had a bias towards affect while the likableness dimension was better represented in anterior cingulate cortex. Our results do not support a modular view of social knowledge representation. They rather indicate that the brain representation of social concepts implicates a distributed network of regions that involves ‘domain-specific’ social cognitive systems, but with a greater dependence on language-semantic processing.

scholarly journals Brain Activation During Reading in Deep Dyslexia: An MEG Study

2000 ◽  
Vol 12 (4) ◽  
pp. 622-634 ◽  
Author(s):  
Matti Laine ◽  
Riitta Salmelin ◽  
Päivi Helenius ◽  
Reijo Marttila
Keyword(s):  
Semantic Processing ◽  
Semantic Analysis ◽  
Right Hemisphere ◽  
Word Reading ◽  
Brain Activity ◽  
Temporal Cortex ◽  
Single Word ◽  
Lexical Semantic ◽  
Deep Dyslexia ◽  
Single Word Reading

Magnetoencephalographic (MEG) changes in cortical activity were studied in a chronic Finnish-speaking deep dyslexic patient during single-word and sentence reading. It has been hypothesized that in deep dyslexia, written word recognition and its lexical-semantic analysis are subserved by the intact right hemisphere. However, in our patient, as well as in most nonimpaired readers, lexical-semantic processing as measured by sentence-final semantic-incongruency detection was related to the left superior-temporal cortex activation. Activations around this same cortical area could be identified in single-word reading as well. Another factor relevant to deep dyslexic reading, the morphological complexity of the presented words, was also studied. The effect of morphology was observed only during the preparation for oral output. By performing repeated recordings 1 year apart, we were able to document significant variability in both the spontaneous activity and the evoked responses in the lesioned left hemisphere even though at the behavioural level, the patient's performance was stable. The observed variability emphasizes the importance of estimating consistency of brain activity both within and between measurements in brain-damaged individuals.

scholarly journals Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension

2019 ◽  
Author(s):  
Paul Hoffman ◽  
Andres Tamm
Keyword(s):  
Semantic Processing ◽  
Control Function ◽  
Semantic Representation ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Unrelated Word ◽  
Test Case ◽  
Neuroimaging Data ◽  
The Right

AbstractHomonyms are a critical test case for investigating how the brain resolves ambiguity in language and, more generally, how context influences semantic processing. Previous neuroimaging studies have associated processing of homonyms with greater engagement of regions involved in executive control of semantic processing. However, the precise role of these areas and the involvement of semantic representational regions in homonym comprehension remain elusive. We addressed this by combining univariate and multivariate fMRI analyses of homonym processing. We tested whether multi-voxel activation patterns could discriminate between presentations of the same homonym in different contexts (e.g., bark following tree vs. bark following dog). The ventral anterior temporal lobe, implicated in semantic representation but not previously in homonym comprehension, showed this meaning-specific coding, despite not showing increased mean activation for homonyms. Within inferior frontal gyrus (IFG), a key site for semantic control, there was a dissociation between pars orbitalis, which also showed meaning-specific coding, and pars triangularis, which discriminated more generally between semantically related and unrelated word pairs. IFG effects were goal-dependent, only occurring when the task required semantic decisions, in line with a top-down control function. Finally, posterior middle temporal cortex showed a hybrid pattern of responses, supporting the idea that it acts as an interface between semantic representations and the control system. The study provides new evidence for context-dependent coding in the semantic system and clarifies the role of control regions in processing ambiguity. It also highlights the importance of combining univariate and multivariate neuroimaging data to fully elucidate the role of a brain region in semantic cognition.

scholarly journals The Neural Bases of Drawing. A Meta-analysis and a Systematic Literature Review of Neurofunctional Studies in Healthy Individuals

2021 ◽  
Author(s):  
Simona Raimo ◽  
Gabriella Santangelo ◽  
Luigi Trojano
Keyword(s):  
Semantic Processing ◽  
Parietal Lobe ◽  
Functional Neuroimaging ◽  
Meta Analysis ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Extrastriate Cortex ◽  
Healthy Individuals ◽  
Inferior Parietal Lobe ◽  
Wide Range

AbstractDrawing is a multi-component process requiring a wide range of cognitive abilities. Several studies on patients with focal brain lesions and functional neuroimaging studies on healthy individuals demonstrated that drawing is associated with a wide brain network. However, the neural structures specifically related to drawing remain to be better comprehended. We conducted a systematic review complemented by a meta-analytic approach to identify the core neural underpinnings related to drawing in healthy individuals. In analysing the selected studies, we took into account the type of the control task employed (i.e. motor or non-motor) and the type of drawn stimulus (i.e. geometric, figurative, or nonsense). The results showed that a fronto-parietal network, particularly on the left side of the brain, was involved in drawing when compared with other motor activities. Drawing figurative images additionally activated the inferior frontal gyrus and the inferior temporal cortex, brain areas involved in selection of semantic features of objects and in visual semantic processing. Moreover, copying more than drawing from memory was associated with the activation of extrastriate cortex (BA 18, 19). The activation likelihood estimation coordinate-based meta-analysis revealed a core neural network specifically associated with drawing which included the premotor area (BA 6) and the inferior parietal lobe (BA 40) bilaterally, and the left precuneus (BA 7).These results showed that a fronto-parietal network is specifically involved in drawing and suggested that a crucial role is played by the (left) inferior parietal lobe, consistent with classical literature on constructional apraxia.

scholarly journals Developing a Semantic Similarity Judgment Test for Persian Action Verbs and Non-action Nouns in Patients With Brain Injury and Determining its Content Validity

2020 ◽  
Vol 21 (2) ◽  
pp. 154-181
Author(s):  
Tabassom Azimi ◽  
◽  
Zahra-Saddat Qoreishi ◽  
Reza Nilipour ◽  
Morteza Farazi ◽  
...  
Keyword(s):  
Semantic Similarity ◽  
Content Validity ◽  
Semantic Processing ◽  
Similarity Judgment ◽  
Point Scale ◽  
Action Verb ◽  
Lexical Semantic ◽  
Verb Processing ◽  
Action Verbs ◽  
The Brain

Objective: Brain trauma evidences suggest that the two grammatical categories of noun and verb are processed in different regions of the brain due to differences in the complexity of grammatical and semantic information processing. Studies have shown that the verbs belonging to different semantic categories lead to neural activity in different areas of the brain, and action verb processing is related to the activity of motor and pre-motor areas of the brain. Researchers use different tasks to evaluate action verb processing. The most common tasks are action naming and action fluency tasks. Although these types of tasks are sensitive to deficits in action verb processing, they do not specify the nature of the injury. To understand whether dysfunction in action verb processing is due to difficulty in lexical access or specific impairment in semantic processing, it is necessary to design a specific test to evaluate lexical-semantic processing. Semantic Similarity Judgment (SSJ) test targets the lexical-semantic encoding at a deep and controlled processing level. The purpose of the present study was to develop a SSJ test for Persian action verbs and non-action nouns and determine its content validity. Materials & Methods: In this methodological study, 70 Persian action concrete verbs and 80 Persian non-action concrete nouns were first selected. For each word, a semantically related word based on functional, physical, categorical features and similarity in action was selected according to the opinion of 4 experts (3 speech-language pathologists and one linguist) using a 7-point scale. For semantic similarity rating, only the pairs of words with a high semantic similarity score (5 to 7) remained and the rest were omitted. Then, for each pair of semantically related words, a semantically unrelated word was selected. After determining content validity qualitatively by three experts and removing inappropriate items, for matching the two sets of nouns and verbs, the lexical and psycholinguistic characteristics of the remaining words (207 nouns and 156 verbs) including frequency, number of syllables, phonemes, letters, phonological and orthographic neighbors, action association, imageability, familiarity and age of acquisition were extracted by 18 volunteers (13 speech-language pathologists and linguists and 5 parents selected by a convenience sampling method) based on a 7-point scale. The verbs with low action associations and the nouns with high action association were removed and then, the two sets of words were matched for other lexical and psycholinguistic characteristics. Finally, 34 triples of verbs with high action association and 34 triples of nouns with low action association were selected. In both noun and verb sets, the words were chosen in such a way that, in order to judge, the semantic features of the words need to be carefully considered. Data analysis was performed using descriptive statistics and independent t-test.

Lexical/semantic processing in dorsal left inferior frontal gyrus

Neuroreport ◽  
2007 ◽  
Vol 18 (11) ◽  
pp. 1147-1151 ◽  
Author(s):  
Chang Cai ◽  
Takanori Kochiyama ◽  
Kunihiko Osaka ◽  
Jinglong Wu
Keyword(s):  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Left Inferior Frontal Gyrus ◽  
Lexical Semantic

GESTURE RECOGNITION SYSTEM FOR NIGERIAN TRIBAL GREETING POSTURES USING SUPPORT VECTOR MACHINE

2020 ◽  
Vol 5 (2) ◽  
pp. 609
Author(s):  
Segun Aina ◽  
Kofoworola V. Sholesi ◽  
Aderonke R. Lawal ◽  
Samuel D. Okegbile ◽  
Adeniran I. Oluwaranti
Keyword(s):  
Support Vector Machine ◽  
Gesture Recognition ◽  
Recognition Rate ◽  
Recognition Task ◽  
Recognition System ◽  
Human Interaction ◽  
Support Vector ◽  
System A ◽  
Extraction Algorithm ◽  
Gaussian Blur

This paper presents the application of Gaussian blur filters and Support Vector Machine (SVM) techniques for greeting recognition among the Yoruba tribe of Nigeria. Existing efforts have considered different recognition gestures. However, tribal greeting postures or gestures recognition for the Nigerian geographical space has not been studied before. Some cultural gestures are not correctly identified by people of the same tribe, not to mention other people from different tribes, thereby posing a challenge of misinterpretation of meaning. Also, some cultural gestures are unknown to most people outside a tribe, which could also hinder human interaction; hence there is a need to automate the recognition of Nigerian tribal greeting gestures. This work hence develops a Gaussian Blur – SVM based system capable of recognizing the Yoruba tribe greeting postures for men and women. Videos of individuals performing various greeting gestures were collected and processed into image frames. The images were resized and a Gaussian blur filter was used to remove noise from them. This research used a moment-based feature extraction algorithm to extract shape features that were passed as input to SVM. SVM is exploited and trained to perform the greeting gesture recognition task to recognize two Nigerian tribe greeting postures. To confirm the robustness of the system, 20%, 25% and 30% of the dataset acquired from the preprocessed images were used to test the system. A recognition rate of 94% could be achieved when SVM is used, as shown by the result which invariably proves that the proposed method is efficient.

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