The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
David Poeppel - One of the best experts on this subject based on the ideXlab platform.
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sensitivity to temporal Modulation Rate and spectral bandwidth in the human auditory system fmri evidence
Journal of Neurophysiology, 2012Co-Authors: Tobias Overath, Yue Zhang, Dan H Sanes, David PoeppelAbstract:Hierarchical models of auditory processing often posit that optimal stimuli, i.e., those eliciting a maximal neural response, will increase in bandwidth and decrease in Modulation Rate as one ascends the auditory neuraxis. Here, we tested how bandwidth and Modulation Rate interact at several loci along the human central auditory pathway using functional MRI in a cardiac-gated, sparse acquisition design. Participants listened passively to both narrowband (NB) and broadband (BB) carriers (1/4- or 4-octave pink noise), which were jittered about a mean sinusoidal amplitude Modulation Rate of 0, 3, 29, or 57 Hz. The jittering was introduced to minimize stimulus-specific adaptation. The results revealed a clear difference between spectral bandwidth and temporal Modulation Rate: sensitivity to bandwidth (BB > NB) decreased from subcortical structures to nonprimary auditory cortex, whereas sensitivity to slow Modulation Rates was largest in nonprimary auditory cortex and largely absent in subcortical structures. Furthermore, there was no parametric interaction between bandwidth and Modulation Rate. These results challenge simple hierarchical models, in that BB stimuli evoked stronger responses in primary auditory cortex (and subcortical structures) rather than nonprimary cortex. Furthermore, the strong preference for slow Modulation Rates in nonprimary cortex demonstRates the compelling global sensitivity of auditory cortex to Modulation Rates that are dominant in the principal signals that we process, e.g., speech.
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Sensitivity to temporal Modulation Rate and spectral bandwidth in the human auditory system: MEG evidence.
Journal of neurophysiology, 2011Co-Authors: Yadong Wang, David Poeppel, Nai Ding, Nayef Ahmar, Juanjuan Xiang, Jonathan Z SimonAbstract:Slow acoustic Modulations below 20 Hz, of varying bandwidths, are dominant components of speech and many other natural sounds. The dynamic neural representations of these Modulations are difficult to study through noninvasive neural-recording methods, however, because of the omnipresent background of slow neural oscillations throughout the brain. We recorded the auditory steady-state responses (aSSR) to slow amplitude Modulations (AM) from 14 human subjects using magnetoencephalography. The responses to five AM Rates (1.5, 3.5, 7.5, 15.5, and 31.5 Hz) and four types of carrier (pure tone and 1/3-, 2-, and 5-octave pink noise) were investigated. The phase-locked aSSR was detected reliably in all conditions. The response power generally decreases with increasing Modulation Rate, and the response latency is between 100 and 150 ms for all but the highest Rates. Response properties depend only weakly on the bandwidth. Analysis of the complex-valued aSSR magnetic fields in the Fourier domain reveals several neural sources with different response phases. These neural sources of the aSSR, when approximated by a single equivalent current dipole (ECD), are distinct from and medial to the ECD location of the N1m response. These results demonstRate that the globally synchronized activity in the human auditory cortex is phase locked to slow temporal Modulations below 30 Hz, and the neural sensitivity decreases with an increasing AM Rate, with relative insensitivity to bandwidth.
Brian C. J. Moore - One of the best experts on this subject based on the ideXlab platform.
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Detection of frequency Modulation by hearing-impaired listeners: effects of carrier frequency, Modulation Rate, and added amplitude Modulation.
The Journal of the Acoustical Society of America, 2002Co-Authors: Brian C. J. Moore, Ewa SkrodzkaAbstract:It has been proposed that the detection of frequency Modulation (FM) of sinusoidal carriers can be mediated by two mechanisms: a place mechanism based on FM-induced amplitude Modulation (AM) in the excitation pattern, and a temporal mechanism based on phase-locking in the auditory nerve. The temporal mechanism appears to be "sluggish" and does not play a role for FM Rates above about 10 Hz. It also does not play a role for high carrier frequencies (above about 5 kHz). This experiment examined FM detection in three young subjects with normal hearing and four elderly subjects with cochlear hearing loss. Carrier frequencies were 0.25, 0.5, 1, 2, 4, and 6 kHz and Modulation Rates were 2, 5, 10, and 20 Hz. FM detection thresholds were measured both in the absence of AM, and with AM of a fixed depth (m = 0.33) added in both intervals of a forced-choice trial. The added AM was intended to disrupt cues based on FM-induced AM in the excitation pattern. Generally, the hearing-impaired subjects performed markedly more poorly than the normal-hearing subjects. For the normal-hearing subjects, the disruptive effect of the AM tended to increase with increasing Modulation Rate, for carrier frequencies below 6 kHz, as found previously by Moore and Sek [J. Acoust. Soc. Am. 100, 2320-2331 (1996)]. For the hearing-impaired subjects, the disruptive effective of the AM was generally larger than for the normal-hearing subjects, and the magnitude of the disruption did not consistently increase with increasing Modulation Rate. The results suggest that cochlear hearing impairment adversely affects both temporal and excitation pattern mechanisms of FM detection.
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The effect of Modulation Rate on the detection of frequency Modulation and mistuning of complex tones.
The Journal of the Acoustical Society of America, 2000Co-Authors: Robert P Carlyon, Brian C. J. Moore, Christophe MicheylAbstract:Experiment 1 measured frequency Modulation detection thresholds (FMTs) for harmonic complex tones as a function of Modulation Rate. Six complexes were used, with fundamental frequencies (F0s) of either 88 or 250 Hz, bandpass filtered into a LOW (125–625 Hz), MID (1375–1875 Hz) or HIGH (3900–5400 Hz) frequency region. The FMTs were about an order of magnitude greater for the three complexes whose harmonics were unresolved by the peripheral auditory system (F0=88 Hz in the MID region and both F0s in the HIGH region) than for the other three complexes, which contained some resolved harmonics. Thresholds increased with increases in FM Rate above 2 Hz for all conditions. The increase was larger when the F0 was 88 Hz than when it was 250 Hz, and was also larger in the LOW than in the MID and HIGH regions. Experiment 2 measured thresholds for detecting mistuning produced by modulating the F0s of two simultaneously presented complexes out of phase by 180 degrees. The size of the resulting mistuning oscillates at ...
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dependence of frequency Modulation detection on frequency Modulation coherence across carriers effects of Modulation Rate harmonicity and roving of the carrier frequencies
Journal of the Acoustical Society of America, 1997Co-Authors: Shigeto Furukawa, Brian C. J. MooreAbstract:Furukawa and Moore [S. Furukawa and B. C. J. Moore, J. Acoust. Soc. Am. 100, 2299–2312 (1996)] found that the detection of frequency Modulation (FM) imposed on two inharmonically related carriers was better when the FM was coherent across carriers than when it was incoherent. Here, “coherence” refers to whether the pattern of frequency change over time was identical or different across carriers. The present paper was designed to explore three possible mechanisms underlying this effect. Thresholds were measured for the detection of a single cycle of sinusoidal FM imposed on two sinusoidal carriers. The FM of each carrier was equally detectable, as determined in preliminary experiments. A continuous pink-noise background was used to mask the outputs of auditory filters tuned between the two carrier frequencies. The Modulation Rate was either 2.5, 5, or 10 Hz. Three combinations of carrier frequencies were used, varying in the extent to which the carriers were harmonically related (1050 and 2069 Hz; 1100 and...
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Across‐channel processes in frequency Modulation detection
The Journal of the Acoustical Society of America, 1996Co-Authors: Shigeto Furukawa, Brian C. J. MooreAbstract:This study examined whether the detection of frequency Modulation (FM) on two carriers depends on the coherence of the FM across carriers. Psychometric functions were measured for detecting sinusoidal FM of carriers with frequencies 1100 and 2000 Hz. The modulators for the two carriers were either in phase (coherent) or in anti‐phase (incoherent). The Modulation Rate was either 2.5, 5, or 10 Hz. One or more cycles of Modulation were used. The Modulation of each carrier was equally detectable, as determined in a preliminary experiment. A continuous pink noise background was used to mask the outputs of auditory filters tuned between the two carrier frequencies. Detectability was better for coherent FM than for incoherent FM. The effect of FM coherence was greatest at the lowest Modulation Rate, possibly indicating that phase locking plays a role [B. C. J. Moore and A. Sek, J. Acoust. Soc. Am. 97, 2468–2478 (1995)]. The detectability of the coherent FM was well above the value predicted on the assumption tha...
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Effects of carrier frequency, Modulation Rate, and Modulation waveform on the detection of Modulation and the discrimination of Modulation type (amplitude Modulation versus frequency Modulation).
Journal of the Acoustical Society of America, 1995Co-Authors: Brian C. J. Moore, Aleksander SekAbstract:Initially, psychometric functions were measured for the detection of amplitude Modulation (AM) or frequency Modulation(FM), using a two‐alternative forced‐choice (2AFC) task. Carrier frequencies were 125, 1000, and 6000 Hz, and Modulation Rates were 2, 5, and 10 Hz. For the two lower carrier frequencies, FM detection tended to be best at the lowest Modulation Rate while AM detection was best at the highest Rate. For the 6000‐Hz carrier, both AM and FM detection tended to be poorest at the lowest Modulation Rate. Then, pairs of values of AM and FM were selected that would be equally detectable, and psychometric functions were measured for the discrimination of AM from FM, again in a 2AFC task. For carrier frequencies of 125 and 1000 Hz, the ability to discriminate AM from FM was always poorest at the highest Modulation Rate (10 Hz); at this Rate some subjects were essentially unable to discriminate AM from FM when the detectability of the Modulation was relatively low (d’ of 1.16 and below). For a Modulation Rate of 2 Hz, and when the detectability of the Modulation was modeRate (d’ up to about 2), some subjects discriminated the type of Modulation as well as they detected the Modulation. For a carrier frequency of 6000 Hz, the effect of Modulation Rate varied across subjects, but there was still a trend for poorer discrimination of Modulation type at the highest Modulation Rate. It is suggested that FM detection at a 10‐Hz Modulation Rate is based largely on changes in excitation level for all carrier frequencies. For a 2‐Hz Modulation Rate, and for the two lowest carrier frequencies, an extra mechanism, possibly based on phase locking, may play a role in the detection and discrimination of FM. This mechanism may be ineffective at Modulation Rates above about 5 Hz because the stimuli spend insufficient time at frequency extremes. To check on this, psychometric functions were measured for the detection of FM and AM using quasitrapezoidal Modulation with a Rate of five periods per second and carriers of 250, 1000, and 6000 Hz. This produced improvements in performance relative to that obtained with 5‐Hz sinusoidal Modulation and, for the two lower carrier frequencies only, the improvements were markedly greater for FM than for AM detection. This is consistent with the idea that the use of phase‐locking information depends on the time that the stimuli spend at frequency extremes.
Jonathan Z Simon - One of the best experts on this subject based on the ideXlab platform.
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Sensitivity to temporal Modulation Rate and spectral bandwidth in the human auditory system: MEG evidence.
Journal of neurophysiology, 2011Co-Authors: Yadong Wang, David Poeppel, Nai Ding, Nayef Ahmar, Juanjuan Xiang, Jonathan Z SimonAbstract:Slow acoustic Modulations below 20 Hz, of varying bandwidths, are dominant components of speech and many other natural sounds. The dynamic neural representations of these Modulations are difficult to study through noninvasive neural-recording methods, however, because of the omnipresent background of slow neural oscillations throughout the brain. We recorded the auditory steady-state responses (aSSR) to slow amplitude Modulations (AM) from 14 human subjects using magnetoencephalography. The responses to five AM Rates (1.5, 3.5, 7.5, 15.5, and 31.5 Hz) and four types of carrier (pure tone and 1/3-, 2-, and 5-octave pink noise) were investigated. The phase-locked aSSR was detected reliably in all conditions. The response power generally decreases with increasing Modulation Rate, and the response latency is between 100 and 150 ms for all but the highest Rates. Response properties depend only weakly on the bandwidth. Analysis of the complex-valued aSSR magnetic fields in the Fourier domain reveals several neural sources with different response phases. These neural sources of the aSSR, when approximated by a single equivalent current dipole (ECD), are distinct from and medial to the ECD location of the N1m response. These results demonstRate that the globally synchronized activity in the human auditory cortex is phase locked to slow temporal Modulations below 30 Hz, and the neural sensitivity decreases with an increasing AM Rate, with relative insensitivity to bandwidth.
Dan H Sanes - One of the best experts on this subject based on the ideXlab platform.
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sensitivity to temporal Modulation Rate and spectral bandwidth in the human auditory system fmri evidence
Journal of Neurophysiology, 2012Co-Authors: Tobias Overath, Yue Zhang, Dan H Sanes, David PoeppelAbstract:Hierarchical models of auditory processing often posit that optimal stimuli, i.e., those eliciting a maximal neural response, will increase in bandwidth and decrease in Modulation Rate as one ascends the auditory neuraxis. Here, we tested how bandwidth and Modulation Rate interact at several loci along the human central auditory pathway using functional MRI in a cardiac-gated, sparse acquisition design. Participants listened passively to both narrowband (NB) and broadband (BB) carriers (1/4- or 4-octave pink noise), which were jittered about a mean sinusoidal amplitude Modulation Rate of 0, 3, 29, or 57 Hz. The jittering was introduced to minimize stimulus-specific adaptation. The results revealed a clear difference between spectral bandwidth and temporal Modulation Rate: sensitivity to bandwidth (BB > NB) decreased from subcortical structures to nonprimary auditory cortex, whereas sensitivity to slow Modulation Rates was largest in nonprimary auditory cortex and largely absent in subcortical structures. Furthermore, there was no parametric interaction between bandwidth and Modulation Rate. These results challenge simple hierarchical models, in that BB stimuli evoked stronger responses in primary auditory cortex (and subcortical structures) rather than nonprimary cortex. Furthermore, the strong preference for slow Modulation Rates in nonprimary cortex demonstRates the compelling global sensitivity of auditory cortex to Modulation Rates that are dominant in the principal signals that we process, e.g., speech.
Aleksander Sek - One of the best experts on this subject based on the ideXlab platform.
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Tuning in the amplitude Modulation Rate domain
Archives of Acoustics, 2014Co-Authors: Aleksander Sek, Ewa SkrodzkaAbstract:This paper is concerned with a certain form of masking that seems to exist in the Modulation Rate domain. It was shown that clearly audible changes in the amplitude of a 4kHz sinusoidal carrier signal produced by a sinusoidal "probe" modulator were inaudible (masked) in the presence of amplitude changes in the same carrier produced by a "masking" modulator which was a 10Hz wide band of white noise. This type of masking was most effective when the centre Rate of the masking modulator was close or equal to the Modulation Rate of the probe modulator. The pattern of results showed a tuning effect in the Modulation Rate domain. These findings are generally consistent with the concept of a second stage of the filtering that may take place in the auditory system.
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Masking in the Modulation Rate domain
Archives of Acoustics, 2003Co-Authors: J. Lemańska, Aleksander Sek, W. RybickaAbstract:This study examines the amplitude Modulation (AM) detection in the presence of a masking modulating signal. The detection thresholds of sinusoidal amplitude Modulation were measured for a 4 kHz sinusoidal carrier. The masking modulators were a 16 Hz tone, a bandwidth of a low-noise noise centered at 16 Hz with a bandwidth of 2 or 8 Hz, and the gaussian noise centered at 16 Hz with a 8 Hz bandwidth. A 3AFC procedure was used. The results obtained suggest the existence of a masking effect in the Modulation Rate domain. This form of masking is the most effective one when the Modulation frequency of the masking signal is close to the masker or, in the spectral range of masking, to the Modulation signal. These results are consistent with experimental data, which suggest the existence of frequency selectivity and tuning in the amplitude Modulation domain. The results obtained are consistent with the idea of a second stage of filtering in the auditory system by means of so-called Modulation filters. It seems that the auditory system performs a limited resolution spectral analysis of the signal amplitude envelope. However, it is necessary to stress that the frequency selectivity in the amplitude Modulation domain is not so evident as the selectivity in the audio frequency domain.
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Discrimination of the amplitude Modulation Rate
Archives of Acoustics, 2002Co-Authors: J. Lemańska, Aleksander Sek, Ewa SkrodzkaAbstract:This study examines the amplitude Modulation Rate discrimination for sinusoidal and noise carriers. It was shown that the discrimination of AM Rates is a monotonically growing function of Modulation Rate. Higher values of the discrimination thresholds were observed for a narrowband carrier. It appears that in the case of a narrowband noise carrier, the spectral range of the noise envelope is similar to that of the Modulation Rates of the signal (up to 120 Hz). It results in a masking in the Modulation Rate domain and in a much higher threshold growth than that observed for a wideband noise carrier or a sinusoidal carrier. The results are consistent with the idea of the so-called second stage of filtering acting on the envelope of the acoustic signal. This hypothesis postulates the existence of a so-called Modulation filter bank, (MFB), responsible for the frequency selectivity observed in the amplitude Modulation Rate domain. The existence of the MFB suggests that a certain form of the spectral analysis of any acoustic signal envelope may be performed in the auditory system after initial filtering in the auditory filter bank. A model of the Modulation Rate discrimination based either on the classical concept of the excitation patterns or on the Modulation excitation patterns has not accounted for our experimental data. According to both the models, an increase in the frequency discrimination threshold versus Modulation Rate should be slower than that measured in the experiment.
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Effects of carrier frequency, Modulation Rate, and Modulation waveform on the detection of Modulation and the discrimination of Modulation type (amplitude Modulation versus frequency Modulation).
Journal of the Acoustical Society of America, 1995Co-Authors: Brian C. J. Moore, Aleksander SekAbstract:Initially, psychometric functions were measured for the detection of amplitude Modulation (AM) or frequency Modulation(FM), using a two‐alternative forced‐choice (2AFC) task. Carrier frequencies were 125, 1000, and 6000 Hz, and Modulation Rates were 2, 5, and 10 Hz. For the two lower carrier frequencies, FM detection tended to be best at the lowest Modulation Rate while AM detection was best at the highest Rate. For the 6000‐Hz carrier, both AM and FM detection tended to be poorest at the lowest Modulation Rate. Then, pairs of values of AM and FM were selected that would be equally detectable, and psychometric functions were measured for the discrimination of AM from FM, again in a 2AFC task. For carrier frequencies of 125 and 1000 Hz, the ability to discriminate AM from FM was always poorest at the highest Modulation Rate (10 Hz); at this Rate some subjects were essentially unable to discriminate AM from FM when the detectability of the Modulation was relatively low (d’ of 1.16 and below). For a Modulation Rate of 2 Hz, and when the detectability of the Modulation was modeRate (d’ up to about 2), some subjects discriminated the type of Modulation as well as they detected the Modulation. For a carrier frequency of 6000 Hz, the effect of Modulation Rate varied across subjects, but there was still a trend for poorer discrimination of Modulation type at the highest Modulation Rate. It is suggested that FM detection at a 10‐Hz Modulation Rate is based largely on changes in excitation level for all carrier frequencies. For a 2‐Hz Modulation Rate, and for the two lowest carrier frequencies, an extra mechanism, possibly based on phase locking, may play a role in the detection and discrimination of FM. This mechanism may be ineffective at Modulation Rates above about 5 Hz because the stimuli spend insufficient time at frequency extremes. To check on this, psychometric functions were measured for the detection of FM and AM using quasitrapezoidal Modulation with a Rate of five periods per second and carriers of 250, 1000, and 6000 Hz. This produced improvements in performance relative to that obtained with 5‐Hz sinusoidal Modulation and, for the two lower carrier frequencies only, the improvements were markedly greater for FM than for AM detection. This is consistent with the idea that the use of phase‐locking information depends on the time that the stimuli spend at frequency extremes.
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Effects of carrier frequency, Modulation Rate, and Modulation waveform on the detection of Modulation and the discrimination of Modulation type (amplitude Modulation versus frequency Modulation).
The Journal of the Acoustical Society of America, 1995Co-Authors: Brian C. J. Moore, Aleksander SekAbstract:Initially, psychometric functions were measured for the detection of amplitude Modulation (AM) or frequency Modulation (FM), using a two-alternative forced-choice (2AFC) task. Carrier frequencies were 125, 1000, and 6000 Hz, and Modulation Rates were 2, 5, and 10 Hz. For the two lower carrier frequencies, FM detection tended to be best at the lowest Modulation Rate while AM detection was best at the highest Rate. For the 6000-Hz carrier, both AM and FM detection tended to be poorest at the lowest Modulation Rate. Then, pairs of values of AM and FM were selected that would be equally detectable, and psychometric functions were measured for the discrimination of AM from FM, again in a 2AFC task. For carrier frequencies of 125 and 1000 Hz, the ability to discriminate AM from FM was always poorest at the highest Modulation Rate (10 Hz); at this Rate some subjects were essentially unable to discriminate AM from FM when the detectability of the Modulation was relatively low (d' of 1.16 and below). For a Modulation Rate of 2 Hz, and when the detectability of the Modulation was modeRate (d' up to about 2), some subjects discriminated the type of Modulation Rate varied across subjects, but there was still a trend for poorer discrimination of Modulation type at the highest Modulation Rate. It is suggested that FM detection at a 10-Hz Modulation Rate is based largely on changes in excitation level for all carrier frequencies. For a 2-Hz Modulation Rate, and for the two lowest carrier frequencies, an extra mechanism, possibly based on phase locking, may play a role in the detection and discrimination of FM. This mechanism may be ineffective at Modulation Rates above about 5 Hz because the stimuli spend insufficient time at frequency extremes. To check on this, psychometric functions were measured for the detection of FM and AM using quasitrapezoidal Modulation with a Rate of five periods per second and carriers of 250, 1000, and 6000 Hz. This produced improvements in performance relative to that obtained with 5-Hz sinusoidal Modulation and, for the two lower carrier frequencies only, the improvements were markedly greater for FM than for AM detection. This is consistent with the idea that the use of of phase-locking information depends on the time that the stimuli spend at frequency extremes.