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.
Example: An individual who worked for 30 years as a medical doctor retires but starts to volunteer at a domestic violence shelter in a client support capacity. Activity theory is compared and contrasted to disengagement theory and continuity theory as a functionalist theory of social gerontology.