Pictomicrograph shows the<unk>  field in layer IV of the rat somatosensory cortex. Each<unk>  receives input from one whisker. The tissue in the image has been stained with cytochrome oxidase and is 50μm thick. The<unk>  is a region of the somatosensory cortex that is identifiable in some species of rodents and species of at least two other orders and contains the<unk>  field. The<unk> s' of the<unk>  field are regions within cortical layer IV that are visibly darker when stained to reveal the presence of cytochrome c oxidase and are separated from each other by lighter areas called septa. These dark-staining regions are a major target for somatosensory inputs from the thalamus, and each<unk>  corresponds to a region of the body. Due to this distinctive cellular structure, organisation, and functional significance, the<unk>  is a useful tool to understand cortical processing and has played an important role in neuroscience. The majority of what is known about corticothalamic processing comes from studying the<unk> , and researchers have intensively studied the<unk>  as a model of neocortical column. The most distinctive aspect of the<unk>  field are the whisker<unk> s. These structures were first discovered by Woolsey and Van der Loos in 1970. Staining in the whisker<unk> s is more distinct than that in other areas of the somatosensory cortex. Recognizing that the array was similar to that of the vibrissae (whiskers) on the mystacial pad (region where whiskers grow from) of certain mammals, they hypothesized that the<unk> s were the "cortical correlates of the mystacial vibrissae" and that "one<unk>  represents one vibrissa". Whereas small non-whisker areas of<unk>  correspond to large and sometimes overlapping areas of the body, each much larger whisker<unk>  corresponds to a single whisker. As a result, the whisker<unk> s are the focus of the majority of<unk>  research, and<unk> ' is often used to refer primarily to the whisker<unk> s. Consequently, much of this article focuses on rodent whisker<unk> .
Barrel cortex
Postrhinal cortex
Piriform cortex
Retrosplenial cortex
Periaqueductal gray
Brodmann area
Eloquent cortex
Cortical homunculus