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.
Williamsburg is a city in and the county seat of Whitley County, Kentucky, United States. The population was 5,143 at the 2000 census. The city was founded in 1818 and named after William Whitley. The Cumberland River flows through the city.