frequency of transmission

• the impulse carried by a neuron is an action potential.
• All action potentials are the same intensity, producing a depolarisation of + 40 mV. This is the all or nothing rule
• Although the size of action potential is unrelated to the intensity fi the stimulus that caused it, were can still detect the stimuli of different intensities such as loud or quiet noises. Our brains determine the intensity fo the stimulus from the frequency of action potentials arriving in the sensory region fo the brain; a higher frequency of action potentials means that the stimulus is more intense
• When a stimulus is at a higher intensity, more sodium channels are opened in the sensory receptor. This produces more generator potentials; resulting in more frequent action potentials in the sensory neuron. therefore more frequent cation potential entering the central nervous system.