supplementärmotorische

Supplementärmotorische refers to the supplementary motor area (SMA), a region of the frontal cortex in the medial surface of the brain. In German neuroscience literature, the term describes the SMA and its subdivisions, typically distinguished as SMA proper and pre-SMA. The SMA lies on the medial aspect of the frontal lobe, anterior to the primary motor cortex, and is situated on the superior frontal gyrus and adjacent paracentral lobule. It is often described as part of Brodmann area 6, involved in motor planning rather than execution.

Functions and roles of the supplementärmotorische area include the planning and preparation of voluntary movements, especially complex, sequential, or internally generated actions. The SMA is associated with the initiation of movement, temporal organization, and the coordination of movements across both sides of the body (bimanual coordination). It also participates in motor imagery, action sequencing, and aspects of language and speech articulation in some tasks. The SMA works in close interaction with the premotor cortex, primary motor cortex, basal ganglia, and thalamic circuits to transform intention into coordinated movement.

Clinical relevance is evident in lesions or surgical changes to the SMA. Disruption can lead to SMA syndrome, characterized by transient contralateral weakness, reduced spontaneous movement, and impaired speech initiation, with recovery often occurring over weeks to months. Functional imaging shows SMA activation in self-initiated and complex motor tasks, distinguishing it from movements driven primarily by external cues.

Overall, the supplementärmotorische area is a key region for the planning and initiation of voluntary, especially internally guided, movements, and it plays a crucial role in coordinating complex motor sequences.