Cognitive and neural mechanisms underlying visual and semantic processing: implications from 'optic aphasia'

Current literature supports the notion that the recognition of objects, when visually presented, is sub-served by neural structures different from those responsible for the semantic processing of their nouns. However, embodiment foresees that processing observed objects and their verbal labels should share similar neural mechanisms. In a combined behavioral and MEG study, we compared the modulation of motor responses and cortical rhythms during the processing of graspable natural objects and tools, either verbally or pictorially presented. Our findings demonstrate that conveying meaning to an observed object or processing its noun similarly modulates both motor responses and cortical rhythms; being natural graspable objects and tools differently represented in the brain, they affect in a different manner both behavioral and MEG findings, independent of presentation modality. These results provide experimental evidence that neural substrates responsible for conveying meaning to objects overlap with those where the object is represented, thus supporting an embodied view of semantic processing.

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Context matters: Novel metaphors in supportive and non-supportive contexts (Preprint)

10.31219/osf.io/s6j3x ◽

2019 ◽

Author(s):

Franziska Hartung ◽

Nathaniel Klooster ◽

Stacey Humphries ◽

Yoed Kenett

Keyword(s):

Target Word ◽

Semantic Processing ◽

Neural Correlates ◽

Literal Meaning ◽

Neural Mechanisms ◽

Semantic Features ◽

Middle Temporal ◽

Inherent Property ◽

Creative Language

Creative language is defined as linguistic output that is both novel and appropriate. Metaphors are one such example of creative language in which one concept is used to express another by highlighting certain semantic features. While novelty is an inherent property of unfamiliar metaphors, appropriateness depends on the context. The current study tests the hypothesis that the context in which metaphors are encountered affects its processing. We examined the neural effects of comprehending metaphors in context by comparing neural activations in response to novel metaphors and literal sentences that were either embedded in a meaningful narrative or in matched jabberwocky contexts. We found that the neural correlates of processing metaphoric sentences and their literal counterparts are indistinguishable when embedded in a narrative: both conditions activate bilateral areas along the anterior temporal poles, middle temporal gyri, superior temporal sulci, and the angular gyri. Metaphors embedded in a narrative as compared to their identical counterparts embedded in jabberwocky show increased responses in sensorimotor areas that correspond to the modality of the literal meaning of the target word, perhaps reflecting deeper semantic processing. Our results confirm that context affects neural mechanisms for understanding creative ideas.

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Effects of Task Demands on Neural Correlates of Acoustic and Semantic Processing in Challenging Listening Conditions

10.1101/2021.01.22.427847 ◽

2021 ◽

Author(s):

Dhatri S. Devaraju ◽

Amy Kemp ◽

David A. Eddins ◽

Rahul Shrivastav ◽

Bharath Chandrasekaran ◽

...

Keyword(s):

Task Difficulty ◽

Semantic Processing ◽

Neural Correlates ◽

Task Demands ◽

Neural Mechanisms ◽

Acoustic Properties ◽

Lower Probability ◽

Temporal Envelope ◽

Envelope Processing ◽

Listening Strategies

AbstractPurposeListeners shift their listening strategies to prioritize lower-level acoustic information and higher-level semantic information in challenging listening conditions. However, the neural mechanisms underlying different strategies are unclear. The current study examined the extent to which encoding of lower-level acoustic cues is modulated by task demand and relationships with the higher-level semantic processing.MethodElectroencephalography (EEG) was acquired while participants listened to sentences in noise that contained either higher or lower probability final words. Task difficulty was modulated by time available to process responses. Cortical tracking of speech - neural correlates of acoustic temporal envelope processing - were estimated using temporal response functions (TRFs).ResultsTask difficulty did not affect cortical tracking of temporal envelope of speech under challenging listening conditions. No correlations were observed between the cortical tracking of temporal envelope of speech and semantic processes, even after controlling for the effect of individualized signal-to-noise ratios.ConclusionsCortical tracking of temporal envelope of speech and semantic processing are differentially influenced by task difficulty. While increased task demands modulated higher-level semantic processing, cortical tracking of temporal envelope of speech may be influenced by task difficulty primarily when the demand is manipulated in terms of acoustic properties of the stimulus, consistent with an emerging perspective in speech perception.

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963. Linking Time and Space to Identify Neural Mechanisms of Semantic Processing Impairments in Schizophrenia: An ERP-fMRI “Fusion” Study

Biological Psychiatry ◽

10.1016/j.biopsych.2017.02.689 ◽

2017 ◽

Vol 81 (10) ◽

pp. S389-S390

Author(s):

Michael Jacob ◽

Judith Ford ◽

Brian Roach ◽

Vince D. Calhoun ◽

Daniel Mathalon

Keyword(s):

Semantic Processing ◽

Neural Mechanisms ◽

Time And Space

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Common and Differential Neural Mechanisms Supporting Imitation of Meaningful and Meaningless Actions

Journal of Cognitive Neuroscience ◽

10.1162/0898929054985374 ◽

2005 ◽

Vol 17 (9) ◽

pp. 1420-1431 ◽

Cited By ~ 111

Author(s):

Raffaella I. Rumiati ◽

Peter H. Weiss ◽

Alessia Tessari ◽

Ann Assmus ◽

Karl Zilles ◽

...

Keyword(s):

Neural Activity ◽

Semantic Processing ◽

Significant Positive Correlation ◽

Neural Mechanisms ◽

Angular Gyrus ◽

Positive Correlation ◽

Inferior Temporal Gyrus ◽

Direct Mechanism ◽

Action Imitation ◽

The Right

Neuropsychological studies indicate that, after brain damage, the ability to imitate meaningful or meaningless actions can be selectively impaired. However, the neural bases supporting the imitation of these two types of action are still poorly understood. Using PET, we investigated in 10 healthy individuals the neural mechanisms of imitating novel, meaningless actions and familiar, meaningful actions. Data were analyzed using SPM99. During imitation, a significant positive correlation (p < .05, corrected) of regional cerebral blood flow with the amount of meaningful actions was observed in the left inferior temporal gyrus only. In contrast, a significant positive correlation (p < .05, corrected) with the amount of meaningless movements was observed in the right parieto-occipital junction. The direct categorical comparison of imitating meaningful (100%) relative to meaningless (100%) actions showed differential increases in neural activity (p < .001, uncorrected) in the left inferior temporal gyrus, the left parahippocampal gyrus, and the left angular gyrus. The reverse categorical comparison of imitating meaningless (100%) relative to meaningful (100%) actions revealed differential increases in neural activity (p < .001, uncorrected) in the superior parietal cortex bilaterally, in the right parieto-occipital junction, in the right occipital-temporal junction (MT, V5), and in the left superior temporal gyrus. Increased neural activity common to imitation of meaningless and meaningful actions compared to action observation was observed in a network of areas known to be involved in imitation of actions including the primary sensorimotor cortex, the supplementary motor area, and the ventral premotor cortex. These results are compatible with the two-route model of action imitation which suggests that there are at least two mechanisms involved in imitation of actions: a direct mechanism transforming a novel action into a motor output, and a semantic mechanism, on the basis of stored memories, that allows reproductions of known actions. Our results indicate that, in addition to shared neural processes, the direct and the semantic mechanisms that underlie action imitation also draw upon differential neural mechanisms. The direct mechanism underlying imitation of meaningless actions differentially involves visuospatial transformation processes as evidenced by activation of areas belonging to the dorsal stream. In contrast, imitation of meaningful actions differentially involves semantic processing as evidenced by activation of areas belonging to the ventral stream.

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The Semantics of Natural Objects and Tools in the Brain: A Combined Behavioural and MEG Study

10.21203/rs.3.rs-484130/v1 ◽

2021 ◽

Author(s):

Elisa Visani ◽

Davide Rossi Sebastiano ◽

Dunja Duran ◽

Gioacchino Garofalo ◽

Fabio Magliocco ◽

...

Keyword(s):

Semantic Processing ◽

Neural Substrates ◽

Neural Mechanisms ◽

Presentation Modality ◽

Motor Responses ◽

Cortical Rhythms ◽

Natural Objects ◽

Verbal Labels ◽

Recognition Of Objects ◽

The Brain

Abstract Current literature supports the notion that the recognition of objects, when visually presented, is sub-served by neural structures different from those responsible for the semantic processing of their nouns. However, embodiment foresees that processing observed objects and their verbal labels should share similar neural mechanisms. In a combined behavioural and MEG study, we compared the modulation of motor responses and cortical rhythms during the processing of graspable natural objects and tools, either verbally or pictorially presented. Our findings demonstrate that conveying meaning to an observed object or processing its noun similarly modulates both motor responses and cortical rhythms; moreover, natural graspable objects and tools affect in a different manner both behavioural and MEG results, independent of presentation modality. These findings provide experimental evidence that neural substrates responsible for conveying meaning to object overlap with those where the object is represented, thus supporting an embodied view of semantic processing.

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