scholarly journals Auditory cortex activation is modulated nonlinearly by stimulation duration: A functional near-infrared spectroscopy (fNIRS) study

2021 ◽  
Author(s):  
Yi Fan Zhang ◽  
Anne Lasfargue ◽  
Isabelle Berry
Keyword(s):  
Infrared Spectroscopy ◽  
Auditory Cortex ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Signal Quality ◽  
Experimental Setup ◽  
Functional Near Infrared Spectroscopy ◽  
Hearing Research ◽  
Stimulation Parameters ◽  
Signal Saturation

Functional near-infrared spectroscopy (fNIRS) is an increasingly popular method in hearing research. However, few studies have considered efficient stimulation parameters for fNIRS auditory experimental design. The objectives of our study are (1) to characterize the auditory hemodynamic responses to trains of white noise with increasing stimulation durations (8s, 10s, 15s, 20s) in terms of amplitude and response linearity; (2) to identify the most-efficient stimulation duration using fNIRS; and (3) to generalize results to more ecological environmental stimuli. We found that cortical activity is augmented following the increments in stimulation durations and reaches a plateau after about 15s of stimulation. The linearity analysis showed that this augmentation due to stimulation duration is not linear in the auditory cortex, the non-linearity being more pronounced for longer durations (15s and 20s). The 15s block duration that we propose as optimal precludes signal saturation, is associated with a high response amplitude and a relatively short total experimental duration. Moreover, the 15s duration remains optimal independently of the nature of presented sounds. The sum of these findings suggests that 15s stimulation duration used in the appropriate experimental setup allows researchers to acquire optimal fNIRS signal quality.

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
Keyword(s):  
Infrared Spectroscopy ◽  
Auditory Cortex ◽  
Near Infrared Spectroscopy ◽  
Auditory Perception ◽  
Near Infrared ◽  
Alpha Power ◽  
Functional Near Infrared Spectroscopy ◽  
Eeg Data ◽  
Related Potentials ◽  
The Right

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.

scholarly journals Functional Near-Infrared Spectroscopy to Probe State- and Trait-Like Conditions in Chronic Tinnitus: A Proof-of-Principle Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Martin Schecklmann ◽  
Anette Giani ◽  
Sara Tupak ◽  
Berthold Langguth ◽  
Vincent Raab ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Auditory Cortex ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Brain Activity ◽  
Chronic Tinnitus ◽  
Healthy Controls ◽  
Brain Oxygenation ◽  
Functional Near Infrared Spectroscopy ◽  
Proof Of Principle

Objective. Several neuroscience tools showed the involvement of auditory cortex in chronic tinnitus. In this proof-of-principle study we probed the capability of functional near-infrared spectroscopy (fNIRS) for the measurement of brain oxygenation in auditory cortex in dependence from chronic tinnitus and from intervention with transcranial magnetic stimulation.Methods. Twenty-three patients received continuous theta burst stimulation over the left primary auditory cortex in a randomized sham-controlled neuronavigated trial (verum = 12; placebo = 11). Before and after treatment, sound-evoked brain oxygenation in temporal areas was measured with fNIRS. Brain oxygenation was measured once in healthy controls(n=12).Results. Sound-evoked activity in right temporal areas was increased in the patients in contrast to healthy controls. Left-sided temporal activity under the stimulated area changed over the course of the trial; high baseline oxygenation was reduced and vice versa.Conclusions. By demonstrating that rTMS interacts with auditory evoked brain activity, our results confirm earlier electrophysiological findings and indicate the sensitivity of fNIRS for detecting rTMS induced changes in brain activity. Moreover, our findings of trait- and state-related oxygenation changes indicate the potential of fNIRS for the investigation of tinnitus pathophysiology and treatment response.

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