Robust Neuronal Discrimination in Primary Auditory Cortex Despite Degradations of Spectro-temporal Acoustic Details: Comparison Between Guinea Pigs with Normal Hearing and Mild Age-Related Hearing Loss
- 103 Downloads
This study investigated to which extent the primary auditory cortex of young normal-hearing and mild hearing-impaired aged animals is able to maintain invariant representation of critical temporal-modulation features when sounds are submitted to degradations of fine spectro-temporal acoustic details. This was achieved by recording ensemble of cortical responses to conspecific vocalizations in guinea pigs with either normal hearing or mild age-related sensorineural hearing loss. The vocalizations were degraded using a tone vocoder. The neuronal responses and their discrimination capacities (estimated by mutual information) were analyzed at single recording and population levels. For normal-hearing animals, the neuronal responses decreased as a function of the number of the vocoder frequency bands, so did their discriminative capacities at the single recording level. However, small neuronal populations were found to be robust to the degradations induced by the vocoder. Similar robustness was obtained when broadband noise was added to exacerbate further the spectro-temporal distortions produced by the vocoder. A comparable pattern of robustness to degradations in fine spectro-temporal details was found for hearing-impaired animals. However, the latter showed an overall decrease in neuronal discrimination capacities between vocalizations in noisy conditions. Consistent with previous studies, these results demonstrate that the primary auditory cortex maintains robust neural representation of temporal envelope features for communication sounds under a large range of spectro-temporal degradations.
Keywordsvocoder envelope fine structure electrophysiology auditory cortex neural discrimination performance spike timing
Special thanks to Fabien Lhericel and Céline Dubois for taking care of the guinea pig colony and to Dr. Grégoire Levasseur for helping generating high quality figures.
- Ding N, Chatterjee M, Simon JZ (2014) Robust cortical entrainment to the speech envelope relies on the spectro-temporal fine structure. Neuroimage 88:41–46. https://doi.org/10.1016/j.neuroimage.2013.10.054
- Gnansia D, Pressnitzer D, Pean V, Meyer B, Lorenzi C (2010) Intelligibility of interrupted and interleaved speech for normal-hearing listeners and cochlear implantees. Hear Res 265(1–2):46–53. https://doi.org/10.1016/j.heares.2010.02.012
- Hohmann V (2002) Frequency analysis and synthesis using a Gammatone filterbank. Acust Acta Acust 88:433–442Google Scholar
- Nagarajan SS, Cheung SW, Bedenbaugh P, Beitel RE, Schreiner CE, Merzenich MM (2002) Representation of spectral and temporal envelope of twitter vocalizations in common marmoset primary auditory cortex. J Neurophysiol 87(4):1723–1737. https://doi.org/10.1152/jn.00632.2001 CrossRefPubMedGoogle Scholar
- Occelli F, Suied C, Pressnitzer D, Edeline JM, Gourévitch B (2016) A neural substrate for rapid timbre recognition? Neural and behavioral discrimination of very brief acoustic vowels. Cereb Cortex 26(6):2483–2496. https://doi.org/10.1093/cercor/bhv071
- Peters RW, Moore BCJ (1992) Auditory filters and aging: filters when auditory thresholds are normal. In: Cazals Y, Demany L, Horner K (eds) Auditory physiology and perception. Pergamon, Oxford, pp 179–185. https://doi.org/10.1016/B978-0-08-041847-6.50026-5 CrossRefGoogle Scholar
- Rennaker RL, Carey HL, Anderson SE, Sloan AM, Kilgard MP (2007) Anesthesia suppresses nonsynchronous responses to repetitive broadband stimuli. Neuroscience 145(1):357–369. https://doi.org/10.1016/j.neuroscience.2006.11.043 CrossRefPubMedGoogle Scholar
- Romanski LM, Averbeck BB (2009) The primate cortical auditory system and neural representation of conspecific vocalizations. Annu Rev Neurosci 32(1):315–346. https://doi.org/10.1146/annurev.neuro.051508.135431 CrossRefPubMedPubMedCentralGoogle Scholar
- Shannon CE (1948) A mathematical theory of communication. Bell Syst Tech J 27(3):379–423. https://doi.org/10.1002/j.1538-7305.1948.tb01338.x CrossRefGoogle Scholar
- Whitmal NA, Poissant SF, Freyman RL, Helfer KS (2007) Speech intelligibility in cochlear implant simulations: effects of carrier type, interfering noise, and subject experience. J Acoust Soc Am 122(4):2376–2388. https://doi.org/10.1121/1.2773993