课件：动物生理学原理-耳鸣和听觉过敏的神经生物学机制.ppt

3.2 听觉过敏的动物模型(研究较少） Wei Sun, Anchun Deng, Aditi Jayaram, et al. Noise exposure enhances auditory cortex responses related to hyperacusis behavior. Brain Research, 1485 (2012): 108–116 Experimental procedures Animals: Twenty-five adult male Sprague Dawley SD rats (3 –6 months old, 300–500g) Hyperacusis behavioral assessment: The acoustic startle amplitude has been used to evaluate hyperacusis behavior ( Ison et al., 2007; Sun et al., 2009 ). The acoustic startle response for the hyperacusis test was evoked by a narrowband noise burst (50 ms duration) centered at 8 or 16 kHz with 1000 Hz bandwidth from 60 to 110 dB SPL (10 dB step). Noise exposure and hearing evaluation: Rats were exposed to a narrowband noise centered at 12 kHz (1 kHz bandwidth) at 120 dB SPL for 1 hour in a sound proof room. The auditory brainstem response (ABR) was recorded in anesthetized rats before and after noise exposure to monitor their hearing threshold. Electrode implantation for the chronic recording: Eight rats were implanted with low impedance customized electrodes made of Teflon coated tungsten wire (0.3 mm diameter, A-M Systems, W.A.) in the IC and the AC for the field potential recordings. Acoustic stimuli and recordings: Tone-bursts (50 ms duration, 1 ms rise/fall time) were used to elicit responses; sound intensity was varied from 10 to 90 dB SPL (10 dB step). Fig. 5 – The response of the inferior colliculus (IC) before and after noise exposure at (A) 4 kHz, (B) 8 kHz, (C) 16 kHz and (D) 24 kHz. The IC response showed a significant reduction 1 hour after the noise exposure at low intensity at 16 and 24 kHz, but not at 4 and 8 kHz. Results Fig. 6 – Acoustic evoked auditory cortex (AC) response showed a significant increase after noise exposure at (C) 16 kHz and (D)24 kHz showed a significant difference (two-way ANOVA, p 0.05), whereas there was no significant change at (A) 4 and (B) 8 kHz. Fig7 – The average amplitude of acoustic evoked auditory cortex (AC) response at 100