Sentence:  Goldberg (1985) has proposed that the SMA is part of a medial system which is crucial in the programming and fluent execution of movements on the basis of internal models of reality. He hypothesized that there are two stages in the <WSD>microgenesis</WSD> of movement, each stage being a loop consisting of a number of cortical and subcortical structures. The first stage involves the selection of a context-appropriate behavioral strategy, and the second involves the specification of the details required to execute the action. 
Meaning of the word marked with <WSD> tags:  The development, in discrete but generally imperceptible (seemingly continuous) increments, by the human body or brain, of thoughts, motions, or actions.