What happens to your relationships when your emotional perception changes overnight? Because I’m autistic, I have always been oblivious to unspoken cues from other people. My wife, my son and my friends liked my unflappable demeanor and my predictable behavior. They told me I was great the way I was, but I never really agreed.

For 50 years I made the best of how I was, because there was nothing else I could do. Then I was offered a chance to participate in a study at Beth Israel Deaconess Medical Center, a teaching hospital of Harvard Medical School. Investigators at the Berenson-Allen Center there were studying transcranial magnetic stimulation, or T.M.S., a noninvasive procedure that applies magnetic pulses to stimulate the brain. It offers promise for many brain disorders. Several T.M.S. devices have been approved by the Food and Drug Administration for the treatment of severe depression, and others are under study for different conditions. (It’s still in the experimental phase for autism.) The doctors wondered if changing activity in a particular part of the autistic brain could change the way we sense emotions. That sounded exciting. I hoped it would help me read people a little better....

Before the T.M.S., I had fantasized that the emotional cues I was missing in my autism would bring me closer to people. The reality was very different. The signals I now picked up about what my fellow humans were feeling overwhelmed me. They seemed scared, alarmed, worried and even greedy. The beauty I envisioned was nowhere to be found....

And the hardest thing: It cost me a marriage. When I met my former wife (a decade before the T.M.S.), she was seriously depressed. She’d accepted my autistic even keel, and I accepted her often quiet sadness. I never really felt her depression, so we complemented each other. She could read other people much better than I could, and I relied on her for that.