Neural Responses Flashcards
Why are neurons all or none devices?
Fire in full or not at all.
What happens when an VIIIth nerve fiber responds to stimulation? What happens when stimulus is finished?
Initial burst of activity, and then a decline back to a plateau while stimulus is still being fired. Response of fiber drops below baseline for recovery period, and then rises back up to baseline.
What does the nerve relay to the brain?
Intensity and frequency
How does the VIIIth nerve code for frequency/tonotopic organization?
The frequency to which a nerve responds best- responds to many but responds BEST to one.
What is the firing rate hypothesis?
As intensity of sound increases there is a corresponding increase in the average firing rate of the nerve.
What is the number of neurons hypothesis?
More neurons fire to a louder sound.
What are the two types of VIIIth nerve neurons?
Low spontaneous rate for high threshold, and high spontaneous rate for low threshold.
Explain the low spontaneous rate/high threshold neurons.
Require higher level of stimulation to fire, respond to higher end of intensity, have little or no random background firing noise (reason called low spontaneous rate neurons).
Explain high spontaneous rate neurons/low threshold neurons.
Respond at very low signal intensities and display random firing when no stimulus is present.
What does low threshold pick up? High threshold?
Low are used for hearing sound at near threshold or soft levels, and high may pick up where the low threshold fibers stop as intensity increases.
What is a Post Stimulus Time Histogram?
Used to look at data over time.
