scholarly journals Neurophysiological Evaluation of Right-Ear Advantage During Dichotic Listening

2021 ◽  
Vol 12 ◽  
Author(s):  
Keita Tanaka ◽  
Bernhard Ross ◽  
Shinya Kuriki ◽  
Tsuneo Harashima ◽  
Chie Obuchi ◽  
...  
Keyword(s):  
Steady State ◽  
Auditory Cortex ◽  
Dichotic Listening ◽  
Steady State Response ◽  
State Response ◽  
Auditory Steady State Response ◽  
Left And Right ◽  
Ear Advantage ◽  
Right Ear Advantage ◽  
The Right

Right-ear advantage refers to the observation that when two different speech stimuli are simultaneously presented to both ears, listeners report stimuli more correctly from the right ear than the left. It is assumed to result from prominent projection along the auditory pathways to the contralateral hemisphere and the dominance of the left auditory cortex for the perception of speech elements. Our study aimed to investigate the role of attention in the right-ear advantage. We recorded magnetoencephalography data while participants listened to pairs of Japanese two-syllable words (namely, “/ta/ /ko/” or “/i/ /ka/”). The amplitudes of the stimuli were modulated at 35 Hz in one ear and 45 Hz in the other. Such frequency-tagging allowed the selective quantification of left and right auditory cortex responses to left and right ear stimuli. Behavioral tests confirmed the right-ear advantage, with higher accuracy for stimuli presented to the right ear than to the left. The amplitude of the auditory steady-state response was larger when attending to the stimuli compared to passive listening. We detected a correlation between the attention-related increase in the amplitude of the auditory steady-state response and the laterality index of behavioral accuracy. The right-ear advantage in the free-response dichotic listening was also found in neural activities in the left auditory cortex, suggesting that it was related to the allocation of attention to both ears.

Effect of Isoflurane on the Auditory Steady-state Response and on Consciousness in Human Volunteers 

1998 ◽  
Vol 89 (4) ◽  
pp. 844-851 ◽  
Author(s):  
Gilles Plourde ◽  
Chantal Villemure ◽  
Pierre Fiset ◽  
Vincent Bonhomme ◽  
Steven B. Backman
Keyword(s):  
Steady State ◽  
Electrical Response ◽  
Dependent Manner ◽  
Steady State Response ◽  
Concentration Dependent Manner ◽  
Isoflurane Concentration ◽  
State Response ◽  
Auditory Steady State Response ◽  
Prediction Probability ◽  
The Right

Background The auditory steady state response (ASSR) is a sustained electrical response of the brain to auditory stimuli delivered at fast rates (30-50 responses/s). The aim of this study was to evaluate the effect of 0.26-0.50% isoflurane on the ASSR and on consciousness, defined as responsiveness to verbal commands. Methods Ten volunteers (21-31 yr) participated. Isoflurane was administered at three stable, end-tidal concentrations: 0.26%, 0.38%, and 0.50%. The ASSR in response to 18,000 stimuli (500-Hz tonebursts, 10 ms, 82-dB, the right ear, 35-45 bursts/s) was recorded from the vertex with reference to the right mastoid. Recordings were made during baseline, at each isoflurane concentration, and during recovery. Results The mean (SD) ASSR amplitudes were 0.32 (0.23) microV during baseline, 0.24 (0.17) microV during 0.26% isoflurane, 0.09 (0.05) microV during 0.38% isoflurane, 0.04 (0.03) microV during 0.50% isoflurane, and 0.29 (0.33) microV during recovery. The amplitude during baseline and recovery was larger than during 0.38% and 0.50% isoflurane (P < 0.001). The amplitude at 0.26% was larger than at the other concentrations (P < 0.025). The logarithm of the ASSR amplitude was related linearly to the concentration of isoflurane (r = 0.85; P < 0.0001). The prediction probability (Pk) for loss of consciousness was 0.95 for both ASSR and measured isoflurane concentration. An ASSR amplitude < 0.07 microV was always associated with unconsciousness. Conclusions The ASSR is attenuated in a concentration-dependent manner by isoflurane. Suppression of consciousness and maximal attenuation of ASSR occur in the same isoflurane concentration range. Profound attenuation of ASSR appears to reflect unconsciousness, defined as unresponsiveness to verbal commands.

scholarly journals Attenuation of the 40-Hertz Auditory Steady State Response by Propofol Involves the Cortical and Subcortical Generators

2008 ◽  
Vol 108 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Gilles Plourde ◽  
Alfonso Garcia-Asensi ◽  
Steven Backman ◽  
Alain Deschamps ◽  
Daniel Chartrand ◽  
...  
Keyword(s):  
Steady State ◽  
Auditory Cortex ◽  
Auditory Evoked Potentials ◽  
Source Analysis ◽  
Steady State Response ◽  
Dipole Strength ◽  
Healthy Human ◽  
State Response ◽  
Auditory Steady State Response ◽  
40 Hz

Background The 40-Hz auditory steady state response (40-Hz ASSR) provides a reliable marker of anesthetic-induced unconsciousness. Brain electric source analysis indicates that the 40-Hz ASSR arises from cortical and subcortical generators. The authors used source analysis to assess the effect of propofol anesthesia on the cerebral generators of the 40-Hz ASSR. They also examined the effect of propofol on two auditory evoked potentials of cortical origin: the N1 and the sustained potential. Methods Eleven healthy human volunteers were anesthetized with propofol given in target-concentration mode at the minimal concentration causing unconsciousness. The 40-Hz ASSR was recorded before, during, and after anesthesia. The source model consisted of five concurrently active generator dipoles: two in the contralateral auditory cortex (one tangentially oriented, one radially oriented), two in the ipsilateral auditory cortex (same orientations), and one in the midline brainstem. Results During anesthesia, the strength of the cortical and brainstem dipoles was reduced to the same extent (to 54% of baseline for the four cortical dipoles pooled vs. 53% for the brainstem dipole). Dipole strength during anesthesia was significantly less (P < 0.01) than during baseline and recovery for both cortical and brainstem dipoles. The N1 and sustained potential were no longer recordable during anesthesia. Conclusions The attenuation of the 40-Hz ASSR during propofol anesthesia results from a reduction of similar magnitude of the activity of the cortical and brainstem generators. The N1 and sustained potential are so profoundly attenuated during propofol anesthesia that they are no longer recordable from the scalp.

Influence of Encoding and Acoustic Similarity on the Ear Advantage and Lag Effect in Dichotic Listening

1976 ◽  
Vol 19 (1) ◽  
pp. 78-92 ◽  
Author(s):  
Robert C. Beiter ◽  
Donald J. Sharf
Keyword(s):  
Steady State ◽  
Dichotic Listening ◽  
Time Lag ◽  
Acoustic Similarity ◽  
Lag Effects ◽  
Burst Noise ◽  
Lag Effect ◽  
Ear Advantage ◽  
Right Ear Advantage ◽  
The Right

Experiments with simultaneous and time lag dichotic listening conditions were used to test two hypotheses concerning the right ear advantage and lag effect in dichotic listening. One hypothesis is based on the similarity of acoustic spectra, and the other is based on a categorization of speech sounds as being either encoded or not encoded. Natural vowels and consonant-vowel syllables were used to obtain seven different types of speech stimuli: stop vowel syllables, fricative vowel syllables, stop burst noise, fricative noise, stop vowel transitions, fricative vowel transitions, and steady state vowels. The presentation conditions were monaural, simultaneous dichotic, and dichotic with interaural time delays of 15, 30, 60, and 90 msec. With monaural presentation, all stimuli were identifiable above chance levels. For the simultaneous dichotic condition, significant right ear advantages occurred for stop vowel syllables, fricative vowel syllables, stop burst noise, and steady state vowels. For the time lag conditions, stop vowel syllables, stop bursts, and fricative noise produced consistent lag effects, but steady state vowels produced consistent lead effects. In general, the results gave stronger support to the hypothesis of acoustic similarity than to the encoding hypothesis in that stop burst noise produced both a right ear advantage and a lag effect whereas consonant-vowel transitions produced neither a right ear advantage nor a lag effect.

Emotional arousal modifies auditory steady state response in the auditory cortex and prefrontal cortex of rats

Stress ◽  
2019 ◽  
Vol 22 (4) ◽  
pp. 492-500 ◽  
Author(s):  
Yuchen Wang ◽  
Zijie Li ◽  
Zemin Tian ◽  
Xuejiao Wang ◽  
Yingzhuo Li ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Steady State ◽  
Auditory Cortex ◽  
Emotional Arousal ◽  
Steady State Response ◽  
State Response ◽  
Auditory Steady State Response

scholarly journals Laminar Profile of Auditory Steady-State Response in the Auditory Cortex of Awake Mice

2021 ◽  
Vol 15 ◽  
Author(s):  
Zijie Li ◽  
Jinhong Li ◽  
Shuai Wang ◽  
Xuejiao Wang ◽  
Jingyu Chen ◽  
...  
Keyword(s):  
Steady State ◽  
Auditory Cortex ◽  
Field Potential ◽  
Gamma Oscillation ◽  
Steady State Response ◽  
Time Frequency ◽  
State Response ◽  
Brain Surface ◽  
Auditory Steady State Response ◽  
40 Hz

ObjectiveAuditory steady-state response (ASSR) is a gamma oscillation evoked by periodic auditory stimuli, which is commonly used in clinical electroencephalographic examination to evaluate the neurological functions. Though it has been suggested that auditory cortex is the origin of ASSR, how the laminar architecture of the neocortex contributes to the ASSR recorded from the brain surface remains unclear.MethodsWe used a 16-channel silicon probe to record the local field potential and the single-unit spike activity in the different layers of the auditory cortex of unanesthetized mice. Click-trains with a repetition rate at 40-Hz were present as sound stimuli to evoke ASSR.ResultsWe found that the LFPs of all cortical layers showed a stable ASSR synchronizing to the 40-Hz click stimuli, while the ASSR was strongest in the granular (thalamorecipient) layer. Furthermore, time-frequency analyses also revealed the strongest coherence between the signals recorded from the granular layer and pial surface.ConclusionOur results reveal that the 40-Hz ASSR primarily shows the evoked gamma oscillation of thalamorecipient layers in the neocortex, and that the ASSR may be a biomarker to detect the cognitive deficits associated with impaired thalamo-cortical connection.

The Auditory Steady-State Response: Full-Term and Premature Neonates

2002 ◽  
Vol 13 (05) ◽  
pp. 260-269 ◽  
Author(s):  
Barbara Cone-Wesson ◽  
John Parker ◽  
Nina Swiderski ◽  
Field Rickards
Keyword(s):  
Steady State ◽  
Premature Infants ◽  
Modulation Frequency ◽  
Otoacoustic Emission ◽  
Full Term ◽  
Steady State Response ◽  
Pass Rates ◽  
Term Infants ◽  
State Response ◽  
Auditory Steady State Response

Two studies were aimed at developing the auditory steady-state response (ASSR) for universal newborn hearing screening. First, neonates who had passed auditory brainstem response, transient evoked otoacoustic emission, and distortion-product otoacoustic emission tests were also tested with ASSRs using modulated tones that varied in frequency and level. Pass rates were highest (> 90%) for amplitude-modulated tones presented at levels ≥ 69 dB SPL. The effect of modulation frequency on ASSR for 500- and 2000-Hz tones was evaluated in full-term and premature infants in the second study. Full-term infants had higher pass rates for 2000-Hz tones amplitude modulated at 74 to 106 Hz compared with pass rates for a 500-Hz tone modulated at 58 to 90 Hz. Premature infants had lower pass rates than full-term infants for both carrier frequencies. Systematic investigation of ASSR threshold and the effect of modulation frequency in neonates is needed to adapt the technique for screening.

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