These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Tuning curves of the difference tone auditory nerve neurophonic.
    Author: Henry KR.
    Journal: Hear Res; 1996 Sep 15; 99(1-2):160-7. PubMed ID: 8970824.
    Abstract:
    When a pair of tonal stimuli of different frequencies (F1 and F2, where F2 > F1) are simultaneously presented to the ear, an electrical response with a frequency of F2-F1 can be recorded from the round window (RW) of the gerbil's cochlea. By using phase-locked tones of alternating polarity, the cochlear microphonics are canceled, leaving a time-averaged difference tone-auditory nerve neurophonic (DT-ANN). When the F1 frequency ranges from 1.25 to 30 kHz and F2-F1 approximately 900 Hz, a DT-ANN audiogram can be constructed which parallels (but is at least 10 dB more sensitive than) the compound action potential (CAP) audiogram. In addition to this DT response, a smaller magnitude, higher threshold response having a frequency of 2 DT can often be measured. Both the DT-ANN and the 2 DT-ANN show non-monotonic amplitude input-output functions. The DT- and 2 DT-ANN responses can be forward masked. Masking of low level (e.g., 30 dB SPL) probe stimuli results in DT- and 2 DT-ANN V-shaped tuning curves (TC) with low tip thresholds (approximately 20-30 dB SPL) and a tip frequency close to that of F1 and F2. The Q10 dB values of the forward masked DT-ANN TCs ranges from 1.54 to 20.0 for F1 frequencies varying from 2 to 20 kHz, respectively. The V-shaped DT-ANN TCs generated with simultaneous maskers are often flanked, outside their high- and low-frequency slopes, by frequency-intensity domains where the masker enhances the amplitude of the DT-ANN response. These data (1) provide evidence that, in response to low-intensity tones, the DT-ANN is generated by a restricted population of neurons that have characteristic frequencies close to F1 and F2, and (2) provide evidence for sharply tuned, phase-locked activity occurring in response to low-intensity stimuli, by cochlear axons having characteristic frequencies as high as 20 kHz.
    [Abstract] [Full Text] [Related] [New Search]