title: A Neural Substrate for Rapid Timbre Recognition? Neural and Behavioral Discrimination of Very Brief Acoustic Vowels.
abstract: The timbre of a sound plays an important role in our ability to discriminate between behaviorally relevant auditory categories, such as different vowels in speech. Here, we investigated, in the primary auditory cortex (A1) of anesthetized guinea pigs, the neural representation of vowels with impoverished timbre cues. Five different vowels were presented with durations ranging from 2 to 128 ms. A psychophysical experiment involving human listeners showed that identification performance was near ceiling for the longer durations and degraded close to chance level for the shortest durations. This was likely due to spectral splatter, which reduced the contrast between the spectral profiles of the vowels at short durations. Effects of vowel duration on cortical responses were well predicted by the linear frequency responses of A1 neurons. Using mutual information, we found that auditory cortical neurons in the guinea pig could be used to reliably identify several vowels for all durations. Information carried by each cortical site was low on average, but the population code was accurate even for durations where human behavioral performance was poor. These results suggest that a place population code is available at the level of A1 to encode spectral profile cues for even very short sounds.
authors.affiliation: UMR CNRS 9197, Institut de NeuroScience Paris-Saclay (NeuroPSI).|Université Paris-Sud, Institut de NeuroScience Paris-Saclay (NeuroPSI) 91405 Orsay Cedex, France.
authors.forename: F
authors.initials: F
authors.lastname: Occelli
authors.affiliation: Département Action et Cognition en Situation Opérationnelle, Institut de Recherche Biomédicale des Armées, 91223 Brétigny sur Orge, France.
authors.forename: C
authors.initials: C
authors.lastname: Suied
authors.affiliation: UMR CNRS 8248, LSP.|DEC, LSP Ecole Normale Supérieure, 29 rue d'Ulm, 75005 Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Pressnitzer
authors.affiliation: UMR CNRS 9197, Institut de NeuroScience Paris-Saclay (NeuroPSI).|Université Paris-Sud, Institut de NeuroScience Paris-Saclay (NeuroPSI) 91405 Orsay Cedex, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Edeline
authors.affiliation: UMR CNRS 9197, Institut de NeuroScience Paris-Saclay (NeuroPSI).|Université Paris-Sud, Institut de NeuroScience Paris-Saclay (NeuroPSI) 91405 Orsay Cedex, France.
authors.forename: B
authors.initials: B
authors.lastname: Gourévitch
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007257:Information Theory; D016014:Linear Models; D008297:Male; D008839:Microelectrodes; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D009483:Neuropsychological Tests; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D011571:Psychoacoustics; D013061:Speech Acoustics; D013067:Speech Perception / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: electrophysiology; guinea pigs; mutual information; neural code; psychoacoustics