Figure 1. Frequency coding in the nervous system: Threshold stimulus. 1  If a threshold stimulus is applied to a neuron and maintained (top, red trace), action potentials occur at a maximum frequency that is limited by the sum of the absolute and relative refractory periods (bottom, blue trace).
Phyllis, Kentucky. Phyllis is an unincorporated community located in Pike County, Kentucky, United States. U.S. Geological Survey Geographic Names Information System: Phyllis, Kentucky.
Beattyville is a home rule-class city in Lee County, Kentucky, in the United States. The city was formally established by the state assembly as Beatty in 1851 and incorporated in 1872. It was named for Samuel Beatty, a pioneer settler.