Corticobulbar tract. And that includes these upper motor neuron axons that are going to innervate lower motor neurons in the brain stem and because the wiring is a little bit more complicated in the brain stem, we can get some different patterns of weakness with abnormalities of this pathway.
Activity theory (AT; Russian: ÑÐµÐ¾ÑÐ¸Ñ Ð´ÐµÑÑÐµÐ»ÑÐ½Ð¾ÑÑÐ¸) is an umbrella term for a line of eclectic social sciences theories and research with its roots in the Soviet psychological activity theory pioneered by Lev Vygotsky, Alexei Leont'ev and Sergei Rubinstein.
One such concept is the internal plane of action. Activity theory recognises that each activity takes place in two planes: the external plane and the internal plane. The external plane represents the objective components of the action while the internal plane represents the subjective components of the action.