Each of the figures in the diagram below illustrates a train of action potentials in response to a sudden limb movement. The sensory neuron encoding the velocity of the limb movement is illustrated by which figure?
Ans. B. Figure B
- A phasic receptor (rapid adaptation), illustrated by figure B, produces a high frequency burst of action potentials when stimulated.
- The frequency of discharge slows down or stops even though the stimulus is maintained.
- In contrast, a tonic receptor, illustrated in A and C, continues to fire at a frequency proportional to the magnitude of the stimulus for as long as the stimulus is applied.