Temporal Coherence in the Perceptual Organization and Cortical Representation of Auditory Scenes

Elhilali, Mounya; Ma, Ling; Micheyl, Christophe; Oxenham, Andrew J.; Shamma, Shihab A.

doi:10.1016/j.neuron.2008.12.005

Cited by 221 publications

(324 citation statements)

References 76 publications

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“…The responses studied here could supply the more abstract representation hypothesized by Averbeck and Romanski. What are the possible mechanisms underlying this transformation in the representation of sounds? Shamma and coworkers (35,39) suggested that some of these effects could be explained by depression of the thalamo-cortical synapse. Our results suggest that this process may actually occur earlier, because MGB neurons are also less informative about ST receptive fields but keep substantial information about auditory entities.…”

Section: Discussionmentioning

confidence: 99%

Auditory abstraction from spectro-temporal features to coding auditory entities

Chechik

Nelken

2012

Proc. Natl. Acad. Sci. U.S.A.

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The auditory system extracts behaviorally relevant information from acoustic stimuli. The average activity in auditory cortex is known to be sensitive to spectro-temporal patterns in sounds. However, it is not known whether the auditory cortex also processes more abstract features of sounds, which may be more behaviorally relevant than spectro-temporal patterns. Using recordings from three stations of the auditory pathway, the inferior colliculus (IC), the ventral division of the medial geniculate body (MGB) of the thalamus, and the primary auditory cortex (A1) of the cat in response to natural sounds, we compared the amount of information that spikes contained about two aspects of the stimuli: spectro-temporal patterns, and abstract entities present in the same stimuli such as a bird chirp, its echoes, and the ambient noise. IC spikes conveyed on average approximately the same amount of information about spectro-temporal patterns as they conveyed about abstract auditory entities, but A1 and the MGB neurons conveyed on average three times more information about abstract auditory entities than about spectro-temporal patterns. Thus, the majority of neurons in auditory thalamus and cortex coded well the presence of abstract entities in the sounds without containing much information about their spectro-temporal structure, suggesting that they are sensitive to abstract features in these sounds.S ensory systems have evolved to extract relevant information from the continuous flux of sensory stimuli. The cascade of processing stations along a sensory pathway transforms the stimuli so that the higher brain areas can make behaviorally relevant decisions. In the visual system, these transformations have been shown to involve increasingly complex representations: Center-surround thalamic representations feed the simple and complex V1 neurons, eventually feeding face sensitive neurons, which generalize over a large class of behaviorally relevant stimuli (1). In the auditory system, cochlear nerve fibers at the periphery are narrowly tuned in frequency, and neurons in primary cortex have been shown to be sensitive to specific spectrotemporal (ST) patterns (2-4). However, it is unclear whether ST sensitivity fully reflects the information processing performed by cortical neurons. An alternative account of spectro-temporal sensitivity in A1 suggests that cortical neurons "inherit" their sensitivity to ST patterns from their afferent inputs. Indeed, even neurons in the inferior colliculus, the obligatory midbrain auditory station, are sensitive to ST patterns (5, 6).If this alternative hypothesis is true, then auditory cortical neurons may actually be extracting additional, and potentially more abstract, stimulus features. To characterize ST sensitivity, auditory neurons are often analyzed by computing the average stimulus that elicits spikes, yielding the so-called ST receptive field (STRF) (7). Unfortunately, the stimulus average may be a coarse descriptor of the complex features that excite neurons. For example, the average ...

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Section: Discussionmentioning

confidence: 99%

Auditory abstraction from spectro-temporal features to coding auditory entities

Chechik

Nelken

2012

Proc. Natl. Acad. Sci. U.S.A.

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“…However, the relative importance of these factors is still a matter of debate. In particular, while several psychophysical, neurophysiological, and modeling studies of auditory streaming performed during the last thirty years have focused on the importance of spectral-or tonotopic-contrasts for stream segregation (e.g., Hartmann and Johnson, 1991; for a review, see , recent work has emphasized the role of temporal coherence (Elhilali and Shamma, 2008;Elhilali et al, 2009; for a review, see . In this context, the notion of temporal coherence extends that of synchrony, and refers specifically to the repeated synchronous activation of auditory "channels" (or neural populations) tuned to different sound parameters, e.g., different frequencies, or different sound features, e.g., pitch and spatial location.…”

Section: Introductionmentioning

confidence: 99%

Temporal coherence versus harmonicity in auditory stream formation

Micheyl

Kreft

Shamma³

et al. 2013

The Journal of the Acoustical Society of America

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This study sought to investigate the influence of temporal incoherence and inharmonicity on concurrent stream segregation, using performance-based measures. Subjects discriminated frequency shifts in a temporally regular sequence of target pure tones, embedded in a constant or randomly varying multi-tone background. Depending on the condition tested, the target tones were either temporally coherent or incoherent with, and either harmonically or inharmonically related to, the background tones. The results provide further evidence that temporal incoherence facilitates stream segregation and they suggest that deviations from harmonicity can cause similar facilitation effects, even when the targets and the maskers are temporally coherent.

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“…In such tasks, therefore, stream segregation impedes performance. A recent reurophysiological study of auditory streaming has taken advantage of this (Elhilali et al 2009). Conversely, several studies have found that listeners can more accurately recognize a familiar melody, that is temporally interleaved with another melody, if the two melodies form separate streams (Dowling 1973;Hartmann and Johnson 1991;McAdams 2002, 2003).…”

Section: Introductionmentioning

confidence: 99%

Objective and Subjective Psychophysical Measures of Auditory Stream Integration and Segregation

Micheyl

Oxenham

2010

JARO

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The perceptual organization of sound sequences into auditory streams involves the integration of sounds into one stream and the segregation of sounds into separate streams. "Objective" psychophysical measures of auditory streaming can be obtained using behavioral tasks where performance is facilitated by segregation and hampered by integration, or vice versa. Traditionally, these two types of tasks have been tested in separate studies involving different listeners, procedures, and stimuli. Here, we tested subjects in two complementary temporal-gap discrimination tasks involving similar stimuli and procedures. One task was designed so that performance in it would be facilitated by perceptual integration; the other, so that performance would be facilitated by perceptual segregation. Thresholds were measured in both tasks under a wide range of conditions produced by varying three stimulus parameters known to influence stream formation: frequency separation, tone-presentation rate, and sequence length. In addition to these performancebased measures, subjective judgments of perceived segregation were collected in the same listeners under corresponding stimulus conditions. The patterns of results obtained in the two temporaldiscrimination tasks, and the relationships between thresholds and perceived-segregation judgments, were mostly consistent with the hypothesis that stream segregation helped performance in one task and impaired performance in the other task. The tasks and stimuli described here may prove useful in future behavioral or neurophysiological experiments, which seek to manipulate and measure neural correlates of auditory streaming while minimizing differences between the physical stimuli.

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Temporal Coherence in the Perceptual Organization and Cortical Representation of Auditory Scenes

Cited by 221 publications

References 76 publications

Auditory abstraction from spectro-temporal features to coding auditory entities

Auditory abstraction from spectro-temporal features to coding auditory entities

Temporal coherence versus harmonicity in auditory stream formation

Objective and Subjective Psychophysical Measures of Auditory Stream Integration and Segregation

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