scholarly journals Auditory cortex activity measured with functional near-infrared spectroscopy is susceptible to masking by cortical blood stealing

2020 ◽  
Author(s):  
Kurt Steinmetzger ◽  
Zhengzheng Shen ◽  
Helmut Riedel ◽  
André Rupp

ABSTRACTTo validate the use of functional near-infrared spectroscopy (fNIRS) in auditory perception experiments, combined fNIRS and electroencephalography (EEG) data were obtained from normal-hearing subjects passively listening to speech-like stimuli without linguistic content. The fNIRS oxy-haemoglobin (HbO) results were found to be inconsistent with the deoxy-haemoglobin (HbR) and EEG data, as they were dominated by pronounced cerebral blood stealing in anterior- to-posterior direction. This large-scale bilateral gradient in the HbO data masked the right-lateralised neural activity in the auditory cortex that was clearly evident in the HbR data and EEG source reconstructions. When the subjects were subsequently split into subgroups with more positive or more negative HbO responses in the right auditory cortex, the former group surprisingly showed smaller event-related potentials, less activity in frontal cortex, and increased EEG alpha power, all indicating reduced attention and vigilance. These findings thus suggest that positive HbO responses in the auditory cortex may not necessarily be a favourable result when investigating auditory perception using fNIRS. More generally, the results show that the interpretation of fNIRS HbO signals can be misleading and demonstrate the benefits of combined fNIRS-EEG analyses in resolving this issue.

2021 ◽  
Author(s):  
Abigail Fiske ◽  
Carina de Klerk ◽  
Katie Y. K. Lui ◽  
Liam H Collins-Jones ◽  
Alexandra Hendry ◽  
...  

Inhibitory control, a core executive function, emerges in infancy and develops rapidly across childhood. Methodological limitations have meant that studies investigating the neural correlates underlying inhibitory control in infancy are rare. Employing functional near-infrared spectroscopy alongside a novel touchscreen task that measures response inhibition, this study aimed to uncover the neural underpinnings of inhibitory control in 10-month-old infants (N = 135). We found that when inhibition is required, the right prefrontal and parietal cortices were more activated than when there is no inhibitory demand. Further, activation in right prefrontal areas was associated with individual differences in response inhibition performance. This demonstrates that inhibitory control in infants as young as 10 months of age is supported by similar brain areas as in older children and adults. With this study we have lowered the age-boundary for localising the neural substrates of response inhibition to the first year of life.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph F. Geissler ◽  
Jörn Schneider ◽  
Christian Frings

AbstractOptimal mental workload plays a key role in driving performance. Thus, driver-assisting systems that automatically adapt to a drivers current mental workload via brain–computer interfacing might greatly contribute to traffic safety. To design economic brain computer interfaces that do not compromise driver comfort, it is necessary to identify brain areas that are most sensitive to mental workload changes. In this study, we used functional near-infrared spectroscopy and subjective ratings to measure mental workload in two virtual driving environments with distinct demands. We found that demanding city environments induced both higher subjective workload ratings as well as higher bilateral middle frontal gyrus activation than less demanding country environments. A further analysis with higher spatial resolution revealed a center of activation in the right anterior dorsolateral prefrontal cortex. The area is highly involved in spatial working memory processing. Thus, a main component of drivers’ mental workload in complex surroundings might stem from the fact that large amounts of spatial information about the course of the road as well as other road users has to constantly be upheld, processed and updated. We propose that the right middle frontal gyrus might be a suitable region for the application of powerful small-area brain computer interfaces.


2019 ◽  
Author(s):  
T. Gruber ◽  
C. Debracque ◽  
L. Ceravolo ◽  
K. Igloi ◽  
B. Marin Bosch ◽  
...  

AbstractVariations of the vocal tone of the voice during speech production, known as prosody, provide information about the emotional state of the speaker. In recent years, functional imaging has suggested a role of both right and left inferior frontal cortices in attentive decoding and cognitive evaluation of emotional cues in human vocalizations. Here, we investigated the suitability of functional Near-Infrared Spectroscopy (fNIRS) to study frontal lateralization of human emotion vocalization processing during explicit and implicit categorization and discrimination. Participants listened to speech-like but semantically meaningless words spoken in a neutral, angry or fearful tone and had to categorize or discriminate them based on their emotional or linguistic content. Behaviorally, participants were faster to discriminate than to categorize and they processed the linguistic content of stimuli faster than their emotional content, while an interaction between condition (emotion/word) and task (discrimination/categorization) influenced accuracy. At the brain level, we found a four-way interaction in the fNIRS signal between condition, task, emotion and channel, highlighting the involvement of the right hemisphere to process fear stimuli, and of both hemispheres to treat anger stimuli. Our results show that fNIRS is suitable to study vocal emotion evaluation in humans, fostering its application to study emotional appraisal.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Sungmin Cho ◽  
Won Kee Chang ◽  
Jihong Park ◽  
Seung Hyun Lee ◽  
Jongseung Lee ◽  
...  

AbstractPrism Adaptation (PA) is used to alleviate spatial neglect. We combined immersive virtual reality with a depth-sensing camera to develop virtual prism adaptation therapy (VPAT), which block external visual cues and easily quantify and monitor errors than conventional PA. We conducted a feasibility study to investigate whether VPAT can induce behavioral adaptations by measuring after-effect and identifying which cortical areas were most significantly activated during VPAT using functional near-infrared spectroscopy (fNIRS). Fourteen healthy subjects participated in this study. The experiment consisted of four sequential phases (pre-VPAT, VPAT-10°, VPAT-20°, and post-VPAT). To compare the most significantly activated cortical areas during pointing in different phases against pointing during the pre-VPAT phase, we analyzed changes in oxyhemoglobin concentration using fNIRS during pointing. The pointing errors of the virtual hand deviated to the right-side during early pointing blocks in the VPAT-10° and VPAT-20° phases. There was a left-side deviation of the real hand to the target in the post-VPAT phase, demonstrating after-effect. The most significantly activated channels during pointing tasks were located in the right hemisphere, and possible corresponding cortical areas included the dorsolateral prefrontal cortex and frontal eye field. In conclusion, VPAT may induce behavioral adaptation with modulation of the dorsal attentional network.


2021 ◽  
Author(s):  
Sungmin Cho ◽  
Won-Seok Kim ◽  
Jihong Park ◽  
Seung Hyun Lee ◽  
Jongseung Lee ◽  
...  

Unilateral spatial neglect (USN) is common after stroke and associated with poor functional recovery. Prism adaptation (PA) is one of the most supported modality able to ameliorate USN but underapplied due to several issues. Using immersive virtual reality and depth-sensing camera, we developed the virtual prism adaptation therapy (VPAT) to overcome the limitations in conventional PA. In this study, we investigated whether VPAT can induce behavioral adaptations and which cortical area is most significantly activated. Fourteen healthy subjects participated in this study. The experiment consisted of four sequential phases (pre-VAPT, VPAT-10°, VPAT-20°, and post-VPAT) with functional near-infrared spectroscopy recordings. Each phase consisted of alternating target pointing and resting (or clicking) blocks. To find out the most significantly activated area during pointing in different phases (VPAT-10°, VPAT-20°, and Post-VPAT) in contrast to pointing during the pre-VPAT phase, we analyzed changes in oxyhemoglobin concentration during pointing. The pointing errors of the virtual hand deviated to the right-side during early pointing blocks in the VPAT-10°and VPAT-20°phases. There was a left-side deviation of the real hand to the target in the post-VPAT phase. The most significantly activated channels were all located in the right hemisphere, and possible corresponding cortical areas included the dorsolateral prefrontal cortex and frontal eye field. In conclusion, VPAT may induce behavioral adaptation with modulation of the dorsal attentional network. Future clinical trials using multiple sessions of a high degree of rightward deviation VPAT over a more extended period are required in stroke patients with unilateral spatial neglect.


2021 ◽  
Author(s):  
Daniela Gabiatti Donadel ◽  
Maxciel Zortea ◽  
Iraci Lucena da Silva Torres ◽  
Felipe Fregni ◽  
Wolnei Caumo

Abstract We compared the activation pattern at the motor cortex (MC and prefrontal cortex (PFC) based on the delta value (Δ) of oxy-hemoglobin (HbO) by functional near-infrared spectroscopy (fNIRS). We examined the relationship of the ΔHbO based on the peaks at 5°C and 25°C by right-hand immersion in water in 22 fibromyalgia and 19 controls. Fibromyalgia showed a shorter peak latency for HbO at the left MC. In contrast, at the left MC, their HbO increased 117.64% compared to 92.85% in the controls. A receiver operator characteristics (ROC) analysis showed the ΔHbO cutoffs equal to –0.175 at the left and –0.205 at the right PFC offer sensitivity and specificity of at least 80% in screening fibromyalgia compared to controls. In fibromyalgia, a ROC analysis showed that these cutoff points could discriminate those with higher disability due to pain and more severe central sensitization symptoms (CSS). The ROC with the best discriminatory profile was to the CSS score with the ΔHbO at the left PFC (AUC = 0.82, CI 95% = 0.61–100). These results indicate that cortical activation based on the ΔHbO at the PFC might be a sensitive marker to identify those fibromyalgia patients with more severe clinical symptoms.


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