At 71, longtime actor, director and writer Corey Fischer does what he calls “slow theater” — performing twice a week instead of eight shows a week, the standard professional schedule. “When you are young, eight shows a week is doable,” he says, laughing. “Now I’m doing slow theater, and that’s OK.”

The pace does not rule out his powerful stage presence, a little song and a lot of rich memories, especially in Fischer’s new solo show, “Lightning in the Brain,” at the Marsh in San Francisco.

The show was inspired by “our need to remember,” Fischer says, and its title reflects how his doctor described a seizure after Fischer experienced his first one. “A seizure is a sign of too much electricity, a storm in the brain, the doctor said, and the brain shuts down to protect itself,” he explains.

In the 60-minute show, the San Francisco actor shares some of his medical escapades and his experiences “as a newly old man” in a narrative about forgetting and remembering. The narrative and songs cover “young and old love,” and “losing and finding yourself on the streets of 1960s Paris, in Hollywood or in a rusting Chevy van looking for America.“

Fischer worked on the show for more than two years, calling on his friend and longtime collaborator Naomi Newman for assistance along the way. Newman, who directs “Lightning in the Brain,” co-founded the Traveling Jewish Theatre  with Fischer and Albert Greenberg in 1978. The company closed in 2012.

“To some degree, this new show is my way of dealing with the disappearance of TJT, the artistic home that sheltered me for more than half my life,” Fischer says. “It took about a year to get past it before I started writing songs again. One evening Naomi came over to hear what I had, and she suggested I make a theater piece.”

Fischer sat down to write, using the phrase “I remember” as a prompt, and the words flowed. He remembered watching his great-grandmother, dressed in black, playing solitaire. He remembered the sound of his bike’s wooden training wheels scraping on pavement. “All the memories were like tips of icebergs,” he says. About 10 percent of his memories made it into the show.

Two years ago in June, while working on the show, Fischer experienced transient global amnesia, a temporary episode of memory loss that is not triggered by a seizure or a stroke. “That freaked me out,” he says. “I’ve always been the one who remembers everything.” After the 30-minute episode, Fischer began reading a lot about the neuroscience of memory, and found that the connection between memory and storytelling is deep.

“The same part of the brain — the hippocampus — that allows us to make a mental map in order to navigate also allows us to create narrative structures,” he says. “To me, the narratives in theater have always been a form of storytelling, and that scientific connection suddenly seemed so obvious. My writing really took off.”

Seven months later, in January 2015, he suffered a grand mal seizure, and a second seizure that May. He has since switched medications and had no symptoms, and his brain shows no sign of damage.

Fischer recalled that his first inkling that he was aging came when he had heart surgery at 59. After a long recovery, he was back on stage at TJT and back to scuba diving, but he was well aware that he had entered a new stage of life.

“The awareness has come in sudden shifts, a series of rude awakenings,” Fischer says. “Some of them have been questions: Who am I now? What can I do next?”

Theater and Fischer’s Jewish identity have been the two common threads in his life. “I can’t do any work that is not in some sense Jewish, because the theater has always been the way I have been able to express my Jewishness,” he says. “With the new show, it’s my story this time.”

Fischer grew up in Los Angeles, in a “secular, left-wing Jewish home.”

“It was the ’50s, with the [Hollywood] blacklist, the nuclear fears, the racism, the folk music revival,” he says. “One section of the show is about the first time I went to New York at 31, when I discovered more about my Jewish background.”

Fischer hopes that when audiences see “Lightning in the Brain,” they will feel a range of emotions. “As they leave the theater, I’d love for them to hum a tune or two from the show,” he says. “I also want people to look at their own memories, feel the value of that. The act of remembering is important, because out of that comes a sense of hope.”

“Lightning in the Brain,” through July 9 at the Marsh, 1062 Valencia St., S.F. Tickets:$20-$100. www.themarsh.org