Neural encoding of amplitude modulation within the auditory midbrain of squirrel monkeys

Müller-Preuß, P.; Flachskamm, Cornelia; Bieser, A.

doi:10.1016/0378-5955(94)90111-2

Cited by 53 publications

(43 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The manipulations in this study (the onset phase difference, modulation frequency, and modulation depth) cause changes of activity in many parts of the auditory system such as the cochlear nucleus (CN; e.g. Rhode and Greenberg 1994;Joris et al 1994;Moller 1976) and the inferior colliculus (e.g., Nelson and Carney 2007;Krishna and Semple 2000;Langner and Schreiner 1988;Muller-Preuss et al 1994;Rees and Moller 1983). However, very few studies have directly tested the neuronal correlates of signal detection when the masker is temporally modulated (CN: Pressnitzer et al 2001;Neuert et al 2004).…”

Section: Bohlen Et Al: Detection Of Modulated Tones In Modulated Noisementioning

confidence: 98%

Detection of Modulated Tones in Modulated Noise by Non-human Primates

Bohlen

Dylla

Timms

et al. 2014

JARO

View full text Add to dashboard Cite

In natural environments, many sounds are amplitudemodulated. Amplitude modulation is thought to be a signal that aids auditory object formation. A previous study of the detection of signals in noise found that when tones or noise were amplitude-modulated, the noise was a less effective masker, and detection thresholds for tones in noise were lowered. These results suggest that the detection of modulated signals in modulated noise would be enhanced. This paper describes the results of experiments investigating how detection is modified when both signal and noise were amplitude-modulated. Two monkeys (Macaca mulatta) were trained to detect amplitude-modulated tones in continuous, amplitude-modulated broadband noise. When the phase difference of otherwise similarly amplitude-modulated tones and noise were varied, detection thresholds were highest when the modulations were in phase and lowest when the modulations were anti-phase. When the depth of the modulation of tones or noise was varied, detection thresholds decreased if the modulations were antiphase. When the modulations were in phase, increasing the depth of tone modulation caused an increase in tone detection thresholds, but increasing depth of noise modulations did not affect tone detection thresholds. Changing the modulation frequency of tone or noise caused changes in threshold that saturated at modulation frequencies higher than 20 Hz; thresholds decreased when the tone and noise modulations were in phase and decreased when they were anti-phase. The relationship between reaction times and tone level were not modified by manipulations to the nature of temporal variations in the signal or noise. The changes in behavioral threshold were consistent with a model where the brain subtracted noise from signal. These results suggest that the parameters of the modulation of signals and maskers heavily influence detection in very predictable ways. These results are consistent with some results in humans and avians and form the baseline for neurophysiological studies of mechanisms of detection in noise.

show abstract

Section: Bohlen Et Al: Detection Of Modulated Tones In Modulated Noisementioning

confidence: 98%

Detection of Modulated Tones in Modulated Noise by Non-human Primates

Bohlen

Dylla

Timms

et al. 2014

JARO

View full text Add to dashboard Cite

show abstract

“…Despite the behavioral relevance of partially modulated sounds, most studies of AM have used envelopes with 100% (peak to trough) modulation depths (see Joris et al 2004 for a review). Of the few studies that have varied modulation depth, some have shown increases in synchronization correlated to modulation depth but little change in firing rate (Bieser and Müller-Preuss 1996;Müller-Preuss et al 1994) while others see changes in both synchronization and firing rate (Eggermont 1994;Liang et al 2002;Malone et al 2010;Middlebrooks 2008a;Nelson and Carney 2007).…”

mentioning

confidence: 94%

Ability of primary auditory cortical neurons to detect amplitude modulation with rate and temporal codes: neurometric analysis

Johnson

Yin

O’Connor

et al. 2012

Journal of Neurophysiology

View full text Add to dashboard Cite

Amplitude modulation (AM) is a common feature of natural sounds, and its detection is biologically important. Even though most sounds are not fully modulated, the majority of physiological studies have focused on fully modulated (100% modulation depth) sounds. We presented AM noise at a range of modulation depths to awake macaque monkeys while recording from neurons in primary auditory cortex (A1). The ability of neurons to detect partial AM with rate and temporal codes was assessed with signal detection methods. On average, single-cell synchrony was as or more sensitive than spike count in modulation detection. Cells are less sensitive to modulation depth if tested away from their best modulation frequency, particularly for temporal measures. Mean neural modulation detection thresholds in A1 are not as sensitive as behavioral thresholds, but with phase locking the most sensitive neurons are more sensitive, suggesting that for temporal measures the lower-envelope principle cannot account for thresholds. Three methods of preanalysis pooling of spike trains (multiunit, similar to convergence from a cortical column; within cell, similar to convergence of cells with matched response properties; across cell, similar to indiscriminate convergence of cells) all result in an increase in neural sensitivity to modulation depth for both temporal and rate codes. For the across-cell method, pooling of a few dozen cells can result in detection thresholds that approximate those of the behaving animal. With synchrony measures, indiscriminate pooling results in sensitive detection of modulation frequencies between 20 and 60 Hz, suggesting that differences in AM response phase are minor in A1.

show abstract

“…Neural representations of time-varying signals begin at the auditory periphery where auditory-nerve fibers faithfully represent fine structures of complex sounds in their temporal discharge patterns (Johnson, 1980;Joris and Yin, 1992;Palmer, 1982;Wang and Sachs, 1993). At subsequent processing stations along the ascending auditory pathway, the upper limit of the temporal representation of repetitive signals gradually decreases (e.g., cochlear nucleus: Blackburn and Sachs, 1989;Frisina et al, 1990;Wang and Sachs, 1994;Rhode and Greenberg, 1994; inferior colliculus: Langner and Schreiner, 1988;Batra et al, 1989;Muller-Preuss et al, 1994;Krishna and Semple, 2000;Liu et al, 2006; medial geniculate body: Creutzfeldt et al, 1980;de Ribaupierre et al, 1980;Rouiller et al, 1981;Preuss and Muller-Preuss, 1990; Bartlett and Wang, 2007;auditory cortex: Schreiner and Urbas, 1988;de Ribaupierre et al, 1972;Eggermont, 1991Eggermont, , 1994Gaese and Ostwald, 1995;Bieser and Muller-Preuss, 1996;Lu and Wang, 2000;Lu et al, 2001b;Wallace et al, 2002;Liang et al, 2002;Phan and Recanzone, 2007), due to biophysical properties of neurons and temporal integration of converging inputs from one station to the next. By the time neural signals encoding acoustic information reach auditory cortex, temporal firing patterns alone are inadequate to represent the entire range of time-varying sounds.…”

Section: Introductionmentioning

confidence: 99%