(written from a Production point of view)
As an actress, Coulson is best known for her role as Margaret Lanterman, the Log Lady, in twelve episodes of David Lynch's cult television series Twin Peaks. She also played the role in the 1992 prequel film Twin Peaks: Fire Walk with Me. Coulson first met David Lynch in the 1970s. She starred in his 1974 short film The Amputee, playing the title role, before serving as an assistant director and assistant camera operator on his low-budget 1977 horror film Eraserhead. It was during this time that Lynch and Coulson began discussing the idea of a woman who carried a log around with her. Fourteen years later, Lynch created such a character for Coulson when he began writing Twin Peaks. 
She worked with several Star Trek alumni on Twin Peaks, including actors Mädchen Amick, Michael John Anderson, Robert Bauer, Richard Beymer, Miguel Ferrer, Galyn Görg, Joshua Harris, Tony Jay, David L. Lander, Wendy Robie, Brenda Strong, Carel Struycken, Ron Taylor, Clay Wilcox, Clarence Williams III, and Ray Wise. Amick, Anderson, Ferrer, and Wise also appeared in Fire Walk with Me, as did Gary Bullock, James Parks, and Victor Rivers.
Coulson's first project as an assistant camera operator was the 1976 crime drama The Killing of a Chinese Bookie, starring Seymour Cassel. She later assisted with camera work for such films as Moonshine County Express (starring Jeff Corey, Susan Howard, and Morgan Woodward), Starhops (featuring Dick Miller), and Albert Brooks' Modern Romance. She again worked with David Lynch as assistant camera person on the "Cowboy and the Frenchman" segment on the 1988 French mini-series Les Français Vus Par... (The French As Seen By...). Her most recent camera work can be seen in the films Cold Dog Soup (featuring Seymour Cassel, Raymond Cruz, John Fleck, and Raphael Sbarge) and Night on Earth (starring Winona Ryder).
Her other acting credits include the films Trick or Treats, Femme Fatale, and Another You (co-starring Michael J. Pollard, Phil Rubenstein, Vincent Schiavelli, Vanessa Williams, and Biff Yeager), and the 1992 TV movie Ring of the Musketeers (co-starring Corbin Bernsen, John Rhys-Davies, and Branscombe Richmond). Today, Coulson is primarily a stage actress, having worked with the Oregon Shakespeare Festival for over a decade.