With three incessantly interweaving storylines that traverse decades and feature some 20 characters, “Incognito” in fits and snatches vividly portrays scientists and laypeople grappling with the brain’s puzzles. Directed by Allison Arkell Stockman, four actors — Kari Ginsburg, Ixchel Hernández, Marcus Kyd and Gerrad Alex Taylor — persuasively embody all the characters, for the most part successfully distinguishing them by means of accent and demeanor.

Perhaps the most noteworthy figure is Thomas Harvey (Kyd), a pathologist who, called upon to perform the autopsy of Albert Einstein in 1955, removes the great man’s brain and keeps it for decades. (Harvey was a real person; some other characters are inspired by historical figures.) A compelling stage presence, Kyd conveys the hubris and obsession that motivate Thomas, who at one point asserts, “If you can understand the ingredients, the components, that make us who we are, then my God you can understand everything.”

Another scientist, Martha (Ginsburg), a prickly but vulnerable neuropsychologist, is more humble about her work, as well as about her first romance with another woman, the lively Patricia (Hernández). That story’s poignant themes of beleaguered love and valiant scientific effort reverberate more sadly in the tale of Henry (Taylor), a musician who despite debilitating memory loss still pines for his fiancee (Hernández).

Probably best known for “Constellations,” which starred Jake Gyllenhaal on Broadway, Payne in “Incognito” excels at the texture of conversations. Asked by Martha whether she knows the term “confabulation,” Patricia cheekily guesses, “Is it a board game?” (No. It has to do with the brain’s creation of memories.)

The role-juggling performers largely ace the realism and specificity that such dialogue demands. Ginsburg is particularly persuasive in shading exasperation into the Midwestern-nice aura of Harvey’s meatloaf-cooking wife. And Taylor is hilarious as a very stoned listener to Harvey’s self-justifications.

Stockman’s direction maintains a gracefully driving pace as the short vignettes toggle between plotlines. Easily accommodating the action is designer Nephelie Andonyadis’s set, with light-up furnishings that aptly evoke a hip modern clinic.

In one scene, the identity of a minor character is unclear. (The actors wear the same unobtrusive costumes throughout.) More of a consideration is that the relative diffuseness of Payne’s storytelling will not appeal to everyone.

But “Incognito” movingly allows us to share its scientist characters’ wonder at the power and mystery of every human brain. By the play’s end, we’re pretty sure that the contents of our noggins may rival Einstein’s.

Incognito by Nick Payne. Directed by Allison Arkell Stockman; costume design, Frank Labovitz; lighting, Alberto Segarra; sound designer and composer, Sarah O’Halloran; movement director, Emma Jaster; properties, Pamela Weiner. 100 minutes. Tickets: $20-$45. Through March 12 at Source, 1835 14th St. NW. 202-204-7741. ConstellationTheatre.org