“My year of unraveling” is how a despairing Christy Morrill described nightmarish months when his immune system hijacked his brain.

Nature walks are good for you, but can a city stroll be just as good? Walking in nature has been shown to boost physical and mental health, improve cognitive performance, lower stress and restore attention. But researchers say there are also mental-health benefits to walking in urban areas. You just have to find the right path and pay attention to your surroundings. Walking through historic areas of cities can make people feel less stressed and more energized — some researchers say even more so than walking through a park. Or you could simply focus on natural elements during your city walk. Trees in particular seem to make people more relaxed — even if they're on the street.

Having ADHD can pose challenges at work. Common symptoms include trouble concentrating and sitting still. Inattention and hyperactivity also may impact memory, planning and organization. Adults with the disorder may find it difficult to meet deadlines and to contribute during meetings. But ADHD can also be a source of creativity and unique contributions. Some people think of having ADHD as a superpower. Experts share tips on how to thrive in the workplace and turn neurodiversity into a strength.

New research suggests that Americans' risk for developing dementia over a lifetime may be higher than previously thought. A study found that after age 55, people have up to a 4 in 10 chance of eventually developing dementia — if they live long enough. The risk is highest after age 75, but doctors say there are ways to reduce that risk. Controlling blood pressure, diabetes and cholesterol is good for both your brain and your heart. They also urge staying physically and socially active. The study was published Monday in Nature Medicine.

A new study offers the first detailed map of the human brain throughout and after pregnancy. It was published in the journal Nature Neuroscience on Monday. The study looks at one woman's brain but kicks off a large international research project that aims to scan the brains of hundreds and could one day provide clues about disorders like postpartum depression. Researchers say the transition to motherhood affected nearly every part of the brain. More than 80% of the regions they studied had reductions in the volume of gray matter, where thinking takes place. Researchers said this probably reflects the fine-tuning of networks of interconnected nerve cells.