Plasticity of Inferior Colliculus and Auditory Cortex Following Unilateral Deafening in Adult Ferrets

1997 ◽  
pp. 489-499 ◽  
Author(s):  
David R. Moore ◽  
Susan J. France ◽  
David McAlpine ◽  
Jennifer E. Mossop ◽  
Huib Versnel
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus

scholarly journals Disparity in interaural time difference improves the accuracy of neural representations of individual concurrent narrowband sounds in rat inferior colliculus and auditory cortex

2020 ◽  
Vol 123 (2) ◽  
pp. 695-706
Author(s):  
Lu Luo ◽  
Na Xu ◽  
Qian Wang ◽  
Liang Li
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Interaural Time Difference ◽  
Critical Role ◽  
Low Frequency ◽  
Time Difference ◽  
Neural Representation ◽  
Frequency Bands ◽  
Neural Segregation ◽  
Peripheral Auditory System

The central mechanisms underlying binaural unmasking for spectrally overlapping concurrent sounds, which are unresolved in the peripheral auditory system, remain largely unknown. In this study, frequency-following responses (FFRs) to two binaurally presented independent narrowband noises (NBNs) with overlapping spectra were recorded simultaneously in the inferior colliculus (IC) and auditory cortex (AC) in anesthetized rats. The results showed that for both IC FFRs and AC FFRs, introducing an interaural time difference (ITD) disparity between the two concurrent NBNs enhanced the representation fidelity, reflected by the increased coherence between the responses evoked by double-NBN stimulation and the responses evoked by single NBNs. The ITD disparity effect varied across frequency bands, being more marked for higher frequency bands in the IC and lower frequency bands in the AC. Moreover, the coherence between IC responses and AC responses was also enhanced by the ITD disparity, and the enhancement was most prominent for low-frequency bands and the IC and the AC on the same side. These results suggest a critical role of the ITD cue in the neural segregation of spectrotemporally overlapping sounds. NEW & NOTEWORTHY When two spectrally overlapped narrowband noises are presented at the same time with the same sound-pressure level, they mask each other. Introducing a disparity in interaural time difference between these two narrowband noises improves the accuracy of the neural representation of individual sounds in both the inferior colliculus and the auditory cortex. The lower frequency signal transformation from the inferior colliculus to the auditory cortex on the same side is also enhanced, showing the effect of binaural unmasking.

Sensitivity to binaural intensity and phase difference cues in kitten inferior colliculus

1990 ◽  
Vol 64 (2) ◽  
pp. 582-597 ◽  
Author(s):  
B. J. Blatchley ◽  
J. F. Brugge
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Phase Difference ◽  
Central Nucleus ◽  
Intensity Difference ◽  
Monotonic Functions ◽  
Age Related ◽  
Highly Correlated ◽  
Intensity Functions ◽  
Almost All

1. Responses of single neurons to monaural or binaural CF tones delivered through a closed and calibrated sound delivery system were studied in the central nucleus of the inferior colliculus (ICC) in ketamine and barbiturate-anesthetized kittens 4-105 days old. 2. Neurons from young kittens had elevated thresholds, some greater than 100 dB in the youngest kittens tested. Average thresholds in the ICC matched those previously measured in the auditory nerve (AN), cochlear nuclei (CN), and auditory cortex (CTX), suggesting that the drop in threshold as a function of age is primarily determined by development at the periphery. 3. Minimal first-spike latencies were relatively long in the youngest kittens, approaching adult values by the end of the third postnatal week. Latencies were distributed between values previously determined for the CN and auditory cortex and can be attributed to the centripetal development of the auditory system. 4. The range of frequencies that were effective in exciting ICC neurons was restricted in young kittens. Neurons having characteristic frequencies (CFs) greater than 7 kHz were not recorded before postnatal day 10. CF distribution matched that obtained in previous experiments from AN, CN, and CTX, reflecting the development of the cochlea. 5. Both monotonic and nonomonotonic spike count-versus-intensity functions were found in the youngest kittens. There was a tendency for monotonic functions from the youngest kittens to be steeper than those from older kittens. No age-related changes in the shapes of non-monotonic functions were found. 6. Sensitivity to interaural intensity difference (IID), tested by holding the intensity to the excitatory ear at a suprathreshold level and increasing the intensity of the stimulus to the inhibitory ear, was exhibited as early as 8 days after birth. The majority of the cells exhibiting sensitivity to IID (89.5%) were classified as EI cells, and almost all IID sensitive cells had CFs between 3 and 25 kHz. Within our sample the shapes of IID functions, as well as the operating range of the IID functions, closely resembled those obtained from the adult cat. Thresholds of excitation and of inhibition were highly correlated, suggesting that the ipsilateral and contralateral inputs to the ICC develop as a matched set. 7. Sensitivity to interaural phase difference (IPD), tested either by shifting the onset phase of a CF tone to one ear relative to the other or by presenting tones of slightly different frequency to the two ears, was present as early as 12 days after birth.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Responses in the Inferior Colliculus of the Guinea Pig to Concurrent Harmonic Series and the Effect of Inactivation of Descending Controls

2010 ◽  
Vol 103 (4) ◽  
pp. 2050-2061 ◽  
Author(s):  
Kyle T. Nakamoto ◽  
Trevor M. Shackleton ◽  
Alan R. Palmer
Keyword(s):  
Guinea Pig ◽  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Sound Level ◽  
Harmonic Series ◽  
Natural Environments ◽  
Multiple Sources ◽  
Spike Response ◽  
Relative Level ◽  
Communication Calls

One of the fundamental questions of auditory research is how sounds are segregated because, in natural environments, multiple sounds tend to occur at the same time. Concurrent sounds, such as two talkers, physically add together and arrive at the ear as a single input sound wave. The auditory system easily segregates this input into a coherent percept of each of the multiple sources. A common feature of speech and communication calls is their harmonic structure and in this report we used two harmonic complexes to study the role of the corticofugal pathway in the processing of concurrent sounds. We demonstrate that, in the inferior colliculus (IC) of the anesthetized guinea pig, deactivation of the auditory cortex altered the temporal and/or the spike response to the concurrent, monaural harmonic complexes. More specifically, deactivating the auditory cortex altered the representation of the relative level of the complexes. This suggests that the auditory cortex modulates the representation of the level of two harmonic complexes in the IC. Since sound level is a cue used in the segregation of auditory input, the corticofugal pathway may play a role in this segregation.

scholarly journals Amygdala and auditory cortex differentially modulate tonal receptive fields in the inferior colliculus

IBRO Reports ◽  
2019 ◽  
Vol 6 ◽  
pp. S162-S163
Author(s):  
Jeongyoon Lee ◽  
Jeff Lin ◽  
Adam Swiercz ◽  
Zhe Yu ◽  
Paul J. Marvar ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Receptive Fields

The subparafascicular thalamic nucleus of the rat receives projection fibers from the inferior colliculus and auditory cortex

1990 ◽  
Vol 537 (1-2) ◽  
pp. 323-327 ◽  
Author(s):  
Yukihiko Yasui ◽  
Tetsuro Kayahara ◽  
Katsuma Nakano ◽  
Noboru Mizuno
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Thalamic Nucleus
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