עבוד אותות במערכת החושים סמסטר א' תשס"ט mira/senses2008...
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עבוד אותות במערכת החושיםסמסטר א' תשס"ט
http://www.eng.tau.ac.il/~mira/Senses2008
Neural Activity
Spontaneous Neural Activity (4)
The spontaneous neural activity can be described as:
• A stationary, renewal process.• The length of successive intervals are statistically
independent.
Thus• The probability density function of interval length describes
the process
Spontaneous Neural Activity (5)
1(0, )
!n T
p e
p N T n T en
- Interval lengthN(0,T) – number of spikes in the interval T
This figure shows the input-output function of a single fiber. Notice that the firing rate of the neuron increases as the stimulus intensity increases within its dynamic range, and eventually plateaus.
Input-Output Function of a Single Auditory Nerve Fiber
In general, the auditory nerve fibers that have higher levels of spontaneous activity (HSR), have lower thresholds and lower saturation points.
The fibers that have lower levels of spontaneous acitivity (LSR), have higher thresholds and higher saturation points
threshold
saturation
Auditory nerve rate-intensity functions