How can we keep our brains healthy?

You're not at your best when you're stressed. In fact, your brain has evolved over millennia to release cortisol in stressful situations, inhibiting rational, logical thinking but potentially helping you survive, say, being attacked by a lion. Neuroscientist Daniel Levitin thinks there's a way to avoid making critical mistakes in stressful situations, when your thinking becomes clouded -- the pre-mortem. "We all are going to fail now and then," he says. "The idea is to think ahead to what those failures might be."

Did you know that you're 30 times more likely to laugh if you're with somebody else than if you're alone? Cognitive neuroscientist Sophie Scott shares this and other surprising facts about laughter in this fast-paced, action-packed and, yes, hilarious dash through the science of cracking up.

Alzheimer's doesn't have to be your brain's destiny, says neuroscientist and author of "Still Alice," Lisa Genova. She shares the latest science investigating the disease -- and some promising research on what each of us can do to build an Alzheimer's-resistant brain. TED Talks Daily listeners get a special treat after the talk: a catch-up interview with Lisa Genova on the exciting new developments in this field. And to make sure you never miss an episode, subscribe to TED Talks Daily on your favorite podcast platform.

What can we expect our kids to learn if they're hungry or eating diets full of sugar and empty of nutrients? Former White House Chef and food policymaker Sam Kass discusses the role schools can play in nourishing students' bodies in addition to their minds.

Having feelings isn't a sign of weakness -- they mean we're human, says producer and activist Nikki Webber Allen. Even after being diagnosed with anxiety and depression, Webber Allen felt too ashamed to tell anybody, keeping her condition a secret until a family tragedy revealed how others close to her were also suffering. In this important talk about mental health, she speaks openly about her struggle -- and why communities of color must undo the stigma that misreads depression as a weakness and keeps sufferers from getting help.

What is a concussion? Probably not what you think it is. In this talk from the cutting edge of research, bioengineer (and former football player) David Camarillo shows what really happens during a concussion -- and why standard sports helmets don't prevent it. Here's what the future of concussion prevention looks like.

Through treating everything from strokes to car accident traumas, neurosurgeon Jocelyne Bloch knows the brain's inability to repair itself all too well. But now, she suggests, she and her colleagues may have found the key to neural repair: Doublecortin-positive cells. Similar to stem cells, they are extremely adaptable and, when extracted from a brain, cultured and then re-injected in a lesioned area of the same brain, they can help repair and rebuild it. "With a little help," Bloch says, "the brain may be able to help itself."

Can we break bad habits by being more curious about them? Psychiatrist Judson Brewer studies the relationship between mindfulness and addiction -- from smoking to overeating to all those other things we do even though we know they're bad for us. Learn more about the mechanism of habit development and discover a simple but profound tactic that might help you beat your next urge to smoke, snack or check a text while driving.