Hair Cell and Meddis Hair Cell Model

1. Hair Cell and Meddis Hair Cell Model Xiaoxiang Gong

2. Outline • Function of Hair Cells • Hair Cell Model – Meddis Model • Simulation Result for the Meddis Model • Phase Locking

3. Function of Hair Cell

4. Meddis Model for Hair Cell Synaptic cleft Outside the Hair cell Hair cell • Spike Probability is proportional to the amount of transmitter in the synaptic cleft.

5. Simulation Result for Meddis Model -- from Auditory Toolbox • Stimulus: Single tone (1KHz) with amplitude scales on silent background. • Spontaneous rate • Onset rate: the initial peak value • Steady state rate: adaptation level

6. Phase Locking • The auditory nerve will tend to fire at a particular phase of a stimulating low-frequency tone (Period Histogram). So the inter-spike intervals tend to occur at integer multiples of the periods of the tone (Inter-spike Interval Histogram). • Phase locking depends on the stimulus frequency: with high frequency tones (> 3kHz) phase locking gets weaker.

7. Phase Locking-- Construction of Period Histogram

8. Phase Locking-- Period Histogram & Inter-spike Interval Histogram AN fibers fire at integer multiples of the stimulus period, not necessarily on every period

9. Phase Locking-- Period Histograms from Meddis Model • Showing a half-wave rectified version of the stimulus

10. Phase Locking-- Inter-spike Interval Histograms from Meddis Model • AN fibers fire at intervals related to stimulus frequency. For 1KHz sinusoid input