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

2021 ◽  
Author(s):  
Dhatri S. Devaraju ◽  
Amy Kemp ◽  
David A. Eddins ◽  
Rahul Shrivastav ◽  
Bharath Chandrasekaran ◽  
...  

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.

2021 ◽  
Vol 64 (9) ◽  
pp. 3697-3706
Author(s):  
Dhatri S. Devaraju ◽  
Amy Kemp ◽  
David A. Eddins ◽  
Rahul Shrivastav ◽  
Bharath Chandrasekaran ◽  
...  

Purpose Listeners shift their listening strategies between lower level acoustic information and higher level semantic information to prioritize maximum speech intelligibility in challenging listening conditions. Although increasing task demands via acoustic degradation modulates lexical-semantic processing, the neural mechanisms underlying different listening strategies are unclear. The current study examined the extent to which encoding of lower level acoustic cues is modulated by task demand and associations with lexical-semantic processes. Method Electroencephalography was acquired while participants listened to sentences in the presence of four-talker babble 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. Results Task difficulty did not affect cortical tracking of temporal envelope of speech under challenging listening conditions. Neural indices of lexical-semantic processing (N400 amplitudes) were larger with increased task difficulty. No correlations were observed between the cortical tracking of temporal envelope of speech and lexical-semantic processes, even after controlling for the effect of individualized signal-to-noise ratios. Conclusions Cortical tracking of the 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 the 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.


2019 ◽  
Author(s):  
Franziska Hartung ◽  
Nathaniel Klooster ◽  
Stacey Humphries ◽  
Yoed Kenett

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.


2005 ◽  
Vol 17 (10) ◽  
pp. 1667-1678 ◽  
Author(s):  
Regine Oberecker ◽  
Manuela Friedrich ◽  
Angela D. Friederici

Event-related brain potential (ERP) studies of sentence processing in adults have shown that phrase-structure violations are associated with two ERP components: an early left anterior negativity (ELAN) and a late, centro-parietal positivity (P600). Although the ELAN reflects highly automatic first-pass sentence parsing, the P600 has been interpreted to reflect later, more controlled processes. The present ERP study investigates the processing of phrase-structure violations in children below three years of age. Both children (mean age of 2.8 years) and adults passively listened to short active sentences that were either correct or syntactically incorrect. Adults displayed an ELAN that was followed by a P600 to the syntactic violation. Children also demonstrated a biphasic ERP pattern consisting of an early left hemispheric negativity and a late positivity. Both components, however, started later and persisted longer than those observed in adults. The left lateralization of the children's negativity suggests that this component can be interpreted as a child-specific precursor to the ELAN observed in adults. The appearance of the early negativity indicates that the neural mechanisms of syntactic parsing are present, in principle, during early language development.


2020 ◽  
Author(s):  
Chisa Ota ◽  
Tamami Nakano

AbstractBeauty filters, while often employed for retouching photos to appear more attractive on social media, when used in excess cause images to give a distorted impression. The neural mechanisms underlying this change in facial attractiveness according to beauty retouching level remain unknown. The present study used functional magnetic resonance imaging in women as they viewed photos of their own face or unknown faces that had been retouched at three levels: no, mild, and extreme. The activity in the nucleus accumbens (NA) exhibited a positive correlation with facial attractiveness, whereas amygdala activity showed a negative correlation with attractiveness. Even though the participants rated others’ faces as more attractive than their own, the NA showed increased activity only for their mildly retouched own face and the amygdala exhibited greater activation in the others’ faces condition than the own face condition. Moreover, amygdala activity was greater for extremely retouched faces than for unretouched or mildly retouched faces for both conditions. Frontotemporal and cortical midline areas showed greater activation for one’s own than others’ faces, but such self-related activation was absent when extremely retouched. These results suggest that neural activity dynamically switches between the NA and amygdala according to perceived attractiveness of one’s face.


2021 ◽  
pp. 1-24
Author(s):  
Ian A. Quillen ◽  
Melodie Yen ◽  
Stephen M. Wilson

In this study, we investigated how the brain responds to task difficulty in linguistic and non-linguistic contexts. This is important for the interpretation of functional imaging studies of neuroplasticity in post-stroke aphasia, because of the inherent difficulty of matching or controlling task difficulty in studies with neurological populations. Twenty neurologically normal individuals were scanned with fMRI as they performed a linguistic task and a non-linguistic task, each of which had two levels of difficulty. Critically, the tasks were matched across domains (linguistic, non-linguistic) for accuracy and reaction time, such that the differences between the easy and difficult conditions were equivalent across domains. We found that non-linguistic demand modulated the same set of multiple demand (MD) regions that have been identified in many prior studies. In contrast, linguistic demand modulated MD regions to a much lesser extent, especially nodes belonging to the dorsal attention network. Linguistic demand modulated a subset of language regions, with the left inferior frontal gyrus most strongly modulated. The right hemisphere region homotopic to Broca’s area was also modulated by linguistic but not non-linguistic demand. When linguistic demand was mapped relative to non-linguistic demand, we also observed domain by difficulty interactions in temporal language regions as well as a widespread bilateral semantic network. In sum, linguistic and non-linguistic demand have strikingly different neural correlates. These findings can be used to better interpret studies of patients recovering from aphasia. Some reported activations in these studies may reflect task performance differences, while others can be more confidently attributed to neuroplasticity.


2009 ◽  
Vol 1 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Lawrence J. Taylor ◽  
Rolf A. Zwaan

AbstractEmpirical research has shown that the processing of words and sentences is accompanied by activation of the brain's motor system in language users. The degree of precision observed in this activation seems to be contingent upon (1) the meaning of a linguistic construction and (2) the depth with which readers process that construction. In addition, neurological evidence shows a correspondence between a disruption in the neural correlates of overt action and the disruption of semantic processing of language about action. These converging lines of evidence can be taken to support the hypotheses that motor processes (1) are recruited to understand language that focuses on actions and (2) contribute a unique element to conceptual representation. This article explores the role of this motor recruitment in language comprehension. It concludes that extant findings are consistent with the theorized existence of multimodal, embodied representations of the referents of words and the meaning carried by language. Further, an integrative conceptualization of “fault tolerant comprehension” is proposed.


2006 ◽  
Vol 99 (3) ◽  
pp. 226-235 ◽  
Author(s):  
Henrike K. Blumenfeld ◽  
James R. Booth ◽  
Douglas D. Burman

Neurocase ◽  
2000 ◽  
Vol 6 (3) ◽  
pp. 231-244 ◽  
Author(s):  
Christian Lorenzi ◽  
Jocelyne Wable ◽  
Christine Moroni ◽  
Christophe Derobert ◽  
Bruno Frachet ◽  
...  

2020 ◽  
Vol 32 (10) ◽  
pp. 1924-1945
Author(s):  
Lucía Magis-Weinberg ◽  
Ruud Custers ◽  
Iroise Dumontheil

Prospective memory (PM) refers to the cognitive processes associated with remembering to perform an intended action after a delay. Varying the salience of PM cues while keeping the intended response constant, we investigated the extent to which participants relied on strategic monitoring, through sustained, top–down control, or on spontaneous retrieval via transient bottom–up processes. There is mixed evidence regarding developmental improvements in event-based PM performance after the age of 13 years. We compared PM performance and associated sustained and transient neural correlates in 28 typically developing adolescents (12–17 years old) and 19 adults (23–30 years old). Lower PM cue salience associated with slower ongoing task (OT) RTs, reflected by increased μ ex-Gaussian parameter, and sustained increases in frontoparietal activation during OT blocks, both thought to reflect greater proactive control supporting cue monitoring. Behavioral and neural correlates of PM trials were not specifically modulated by cue salience, revealing little difference in reactive control between conditions. The effect of cue salience was similar across age groups, suggesting that adolescents are able to adapt proactive control engagement to PM task demands. Exploratory analyses showed that younger, but not older, adolescents were less accurate and slower in PM trials relative to OT trials than adults and showed greater transient activation in PM trials in an occipito-temporal cluster. These results provide evidence of both mature and still maturing aspects of cognitive processes associated with implementation of an intention after a delay during early adolescence.


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