Editing Barrel cortex (section)

== Organisation of the barrel fields ==
[[File:Labeled40xVibrissae.jpg|thumb|200px|Pictomicrograph shows the posteromedial barrel subfield in layer IV of the rat somatosensory cortex. Barrels in the PMBSF are particularly large and distinct. The tissue in the image has been stained with cytochrome oxidase and is 50μm thick.]]

The barrel field, like many regions of cortex, is organised into a [[topographic map (neuroanatomy)|topographic map]]. In the case of the barrel field, the map is somatotopic - based on the arrangement of body parts. Areas corresponding to the nose and mouth are more rostral and lateral in the map, the forelimb, hindlimb and trunk are more medial, with the forelimb rostral of the hindlimb, and the whisker barrel subfields - the posteromedial barrel subfield, which corresponds to the major facial whiskers (the mystacial vibrissae), and the anteriolateral barrel subfield, which corresponds to the smaller whiskers of the face - are caudal and lateral. Although the whiskers make up a relatively small portion of the animal, they dominate the somatotopic map.<ref>[[#refHoover2003|Hoover et al., 2003]]</ref><ref>[[#refEnriquez-Barreto|Enriquez-Barreto et al., 2012]]</ref>

=== Barrels of the major facial whiskers  ===
The barrels that correspond to the major facial whiskers (mystacial vibrissae) are contained within the posteromedial barrel subfield (PMBSF). The barrels here are the largest and most elliptical in shape and have a striking topographical organization that is identical to that of the whiskers; they are organized into 5 rows of 4-7 large whiskers that run close to parallel with the bridge of the nose.<ref name="ReferenceA">[[#refWoolsey1970|Woolsey & Van der Loos, 1970]]</ref> The organisation of the mystacial vibrissae and corresponding barrels is so consistent that there is a naming convention to identify each whisker in rats and mice. Rows are designated A to E from top to bottom, and columns of whiskers within each row are numbered from back to front. The first four rows also have an additional whisker behind column 1, which is designated with a lower case letter or a Greek letter (α, β, γ, or δ). These four whiskers are also called straddlers.