Late Adulthood: 40s and beyond

When you lose your keys or forget a name, it may feel like your brain isn’t working as well as it used to. But new research dispels the belief that plasticity, the brain’s capacity to respond to change, diminishes in the adult and aging brain.

Harnett’s lab recently showed the presence of “silent synapses,” connections that are inactive until they’re recruited to help form new memories, in adult mice. These synapses had long been associated with early development, but Harnett and his lab have now also confirmed their widespread presence in adult human brains across ages and different regions.

“Everyone feels like plasticity goes away as you get older and neurons just die,” said Harnett. “Here we found something that’s really robust. It’s like, hey, there’s all these silent synapses and all this extra plasticity capacity in the adult cortex.”

40 to 65

In the 40s and beyond, life shifts toward the challenging roles of adulthood — career, caring for family and giving back to the next generation. Because of how variable individual experiences can be, brain milestones are also trickier to set at specific ages later in life.

A 50-year-old who is highly social and regularly exercising, traveling or volunteering might have a “younger” brain than a 50-year-old who rarely engages in enriching activities.

Research suggests that older adults who engage in memory training tasks, crossword puzzles and even video games can improve some cognitive functions, but the mechanisms underlying those findings are still unknown.

65 and beyond

Late in life, the brain does shrink in size and can begin to degenerate. Yet, older individuals also have the potential for greater wisdom built off a lifetime of experiences. Some researchers have suggested that the brain circuitry tied to emotional processing and moral decision-making might be involved in different components of wisdom, though that research is still limited.

“I don’t think that we provide the respect to the aging and the wisdom that they’ve accumulated throughout a life span,” said Casey.