physiology hw 2

physiology hw 2 - February 12, 2008 Physiology 42-202...

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February 12, 2008 Physiology 42-202 Homework 2 1. The brain decodes the type, intensity, duration, and location of a stimulus by sensory coding. The type of stimulus is coded by the receptor and pathway activated. Many times, the brain may integrate data from more than one sensory system. For example, we do not have wetness receptors, but when can tell when our skin is wet because of thermoreceptors touch receptors. Stimulus intensity is determined by action potential frequency (frequency coding) and the number of receptors activated (population coding). The brain decodes the intensity of the stimulus by receiving the frequency of the action potential sent to the brain by the receptor. (This is termed frequency modulation ). A stronger stimulus produces a stronger depolarizations. This means that the second action potential can be generated faster than weaker depolarizations. As a result threshold is reached with higher frequency. For population coding, a stronger stimulus activates more receptors, and a greater frequency of action potentials is transmitted to the brain, telling the brain that the stimulus is stronger. If the multiple receptors are all related to a single afferent neuron, the generated potentials can be summed. If they are associated with different afferent neurons, more of these neurons
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This note was uploaded on 03/30/2010 for the course BIO 42202 taught by Professor Sanders during the Spring '10 term at Carnegie Mellon.

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physiology hw 2 - February 12, 2008 Physiology 42-202...

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