scholarly journals Comodulation masking release in the inferior colliculus by combined signal enhancement and masker reduction

2017 ◽  
Vol 117 (2) ◽  
pp. 853-867 ◽  
Author(s):  
Jan-Philipp Diepenbrock ◽  
Marcus Jeschke ◽  
Frank W. Ohl ◽  
Jesko L. Verhey

Auditory signals that contain coherent level fluctuations of a masker in different frequency regions enhance the detectability of an embedded sinusoidal target signal, an effect commonly known as comodulation masking release (CMR). Neural correlates have been proposed at different stages of the auditory system. While later stages seem to suppress the response to the masker, earlier stages are more likely to enhance their response to the signal when the masker is comodulated. Using a flanking band masking paradigm, the present study investigates how CMR is represented at the level of the inferior colliculus of the Mongolian gerbil. The responses to a target signal at various sound pressure levels in three different masking conditions were compared. In one condition the masker was a 10-Hz amplitude modulated sinusoid centered at the signal frequency while in the other two conditions six off-frequency carriers (flanking bands) were added. For 64 of a total of 94 units, the addition of comodulated flanking bands to the on-frequency masker did not change the response to the target signal. The remaining 30 units showed a change that enhanced target detectability if coherent flanking bands were added, indicative of CMR. The current data demonstrate that the response characteristics of these neurons represent an intermediate stage between the representation in the cochlear nucleus and the auditory cortex by increasing the response during the signal intervals and decreasing the response for the following masker portions. NEW & NOTEWORTHY The detection of comodulation, i.e., coherent level fluctuations in different frequency regions, is an important feature of speech recognition. In this study, we demonstrate how the representation of a signal in comodulated masking conditions changes along the auditory pathway by using a stimulus paradigm from the cochlea nucleus for the first time in the inferior colliculus. This happens on a timescale that makes corticocollicular feedback a likely candidate as the source.

1990 ◽  
Vol 33 (1) ◽  
pp. 96-102 ◽  
Author(s):  
Kathleen Veloso ◽  
Joseph W. Hall ◽  
John H. Grose

Frequency selectivity and comodulation masking release (CMR) for a 1000-Hz signal frequency were examined in 6-year-old children and adults. An abbreviated measure of frequency selectivity was also conducted for a 500-Hz signal. Frequency selectivity was measured using a notched-noise masking method, and CMR was measured using narrow bands of noise whose amplitude envelopes were either uncorrelated or correlated. There were 6 listeners in each age group. No differences were observed between the adults and children for either auditory measure. Similarly, no differences were observed in the ability to detect a pure-tone signal in a relatively wideband noise masker. When the masking noise was narrowband, however, the masked thresholds of the children were higher than those of the adults. Two characteristics that distinguish narrowband noise from wideband noise are: (1) narrowband noise has a pitch quality corresponding to its center frequency, whereas wideband noise does not have a definite pitch; (2) the intensity fluctuations are relatively greater in narrowband noise than in wideband noise. This may suggest that 6-year-old children have a reduced ability to detect signals in noise backgrounds where the signal has perceptual qualities similar to the noise, or in noise backgrounds having a high degree of fluctuation.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1612
Author(s):  
Andrea Paut ◽  
Ante Prkić ◽  
Ivana Mitar ◽  
Perica Bošković ◽  
Dražan Jozić ◽  
...  

A novel ion-selective electrode with membranes based on iron(III) phosphate and silver sulfide integrated into a completely new electrode body design has been developed for the determination of iron(III) cations. The best response characteristics with linear potential change were found in the iron(III) concentration range from 3.97× 10−5 to 10−2 mol L−1. The detection limit was found to be 2.41× 10−5 mol L−1 with a slope of –20.53 ± 0.63 and regression coefficient of 0.9925, while the quantification limit was 3.97× 10−5 M. The potential change per concentration decade ranged from –13.59 ± 0.54 to –20.53 ± 1.56 for Electrode Body 1 (EB1) and from –17.28 ± 1.04 to –24 ± 1.87 for Electrode Body 2 (EB2), which is presented for the first time in this work. The prepared electrode has a long lifetime and the ability to detect changes in the concentration of iron cations within 20 s. Membrane M1 showed high recoveries in the determination of iron cations in iron(III) standard solutions (98.2–101.2%) as well as in two different pharmaceuticals (98.6–106.5%). This proves that this type of sensor is applicable in the determination of ferric cations in unknown samples, and the fact that all sensor parts are completely manufactured in our laboratory proves the simplicity of the method.


2015 ◽  
Vol 138 (2) ◽  
pp. 1194-1205
Author(s):  
Ramona Grzeschik ◽  
Björn Lübken ◽  
Jesko L. Verhey

2011 ◽  
Vol 129 (5) ◽  
pp. 3181-3193 ◽  
Author(s):  
Simon A. Goldman ◽  
Thomas Baer ◽  
Brian C. J. Moore

1989 ◽  
Vol 42 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Robert P. Carlyon ◽  
Søren Buus ◽  
Mary Florentine

2013 ◽  
Vol 481 ◽  
pp. 146-149 ◽  
Author(s):  
Chang Ju Lee ◽  
Hyeon Gu Cha ◽  
Seul Ki Hong ◽  
Seung Hyun Doh ◽  
Yi Sak Koo ◽  
...  

We demonstrated a metal-semiconductor-metal type GaN UV sensor for the first time by using multi-layer graphene as a Schottky electrode. Multi-layer graphene shows good Schottky electrode characteristic and fabricated UV sensor shows good UV response characteristics. The maximum dark current density and photo-responsive current density were 6.42 × 10-9 A/cm2 and 5.57 × 10-5 A/cm2 at the 10 V bias, respectively. UV/visible rejection ratios were higher than 103 with each applied bias from 1 V to 15 V.


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