<sod>nan<eod>
<sod>The BP, more specifically, is composed of movement related cortical potentials (MRCPs)<ref name="Rehab Journal">Green, J.B., Arnold P.A., Rozhkov, L., Strother, D.M., & Garrott, N. (2003) [http://www.rehab.research.va.gov/jour/03/40/3/pdf/Green.pdf   Bereitschaft (readiness potential)and supplemental motor area interaction in movement generation: Spinal cord injury and normal subjects] Journal of Rehabilitation Research and Development, 40(3), 225-234.</ref> the peak being the MP or Motor potential. MRCPs tend to resemble a "set of plans" used by the cortex for the generation and control of movement. The BP is activated by voluntary movements involving the SMA and the somatosensory cortex in movement preparation and initiation.  Initially only the late BP was considered to be specific for the site of movement and the early BP was thought to be characterized by more general preparation for upcoming movements.  However, over the past couple of decades the early BP is considered to perhaps also be site specific within the supplementary motor area (SMA) and the lateral premotor cortex.<ref name="WhatisBP"/>  Using [[principal component analysis]] and [[functional magnetic resonance imaging]] (fMRI) the main source of early BP was determined to be Area 6 of the precentral gyrus bilaterally, and the main sources of late BP were determined to be Area 4 (also known as the Primary Motor Cortex) and Area 6.  The current consensus is that the early BP starts first in the SMA, including pre-SMA and SMA proper, and then approximately 400ms later in the lateral premotor cortices bilaterally prior to the movement onset, and the late BP starts in the M1 and premotor cortex contralaterally.<ref name="WhatisBP"/><eod>