pre-SMA
Acronym:
The term pre-SMA refers to the more anterior of two parts of mesial premotor cortex in the human and the macaque. It is defined on the basis of internal structure, connections and function ( Matelli-2004 ). In both species it is located caudally on the mesial surface of the superior frontal gyrus. In the human it is associated with area 6a beta of Vogts, and its posterior boundary correlates with the VCA line; in the macaque it is known as area F6.
Unlike other parts of motor cortex, whose primary inputs are from visual and somatosensory areas of the parietal lobe, the pre-SMA in the macaque has primary inputs from area 46 of Walker (caudal parts of the middle frontal gyrus and inferior frontal gyrus) and banks of the anterior cingulate sulcus as well. It is regarded as a convergence zone for inputs from working memory, motivation and perception as triggers of complex actions.
Stimulation of the area in the human can be associated with a conscious urge to move the arm or a sense that it is about to move. The area is activated as a person decides the direction of an action, such as a finger movement, in a task where any of several directions is appropriate. It is involved in learning sequential movement patterns. For example, the hand area is activated in a pianist playing an unfamiliar piece, whereas the SMA proper is activated as he plays much-practiced scales. The area is activated when a person holds in mind the appropriate response to a stimulus until the opportunity to respond arrives ( Geyer-2012 ). The more posterior part of mesial premotor cortex is SMA proper.
Also known as: preSMANeuroNames ID : 3177
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