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.
Madison County is a county located in the U.S. state of Kentucky. As of the 2010 census, the population was 82,916. Its county seat is Richmond. The county is named for Virginia statesman James Madison, who later became the fourth President of the United States. Madison County is part of the Richmond-Berea, KY Micropolitan Statistical Area, which is also included in the Lexington-Fayette-Richmond-Frankfort, KY Combined Statistical Area.