Neurologists involved in animal research studies of cognitive function see analogies in humans that suggest mental exercise reduces loss of brain mass. Which of the following statements describe their findings?
Older adults who continue complex mental activities can delay or even reverse decline in brain mass that is part of normal aging
Mental exercise can only slow normal decline in brain mass that is part of normal aging, but no amount of exercise can delay or reverse it
Mental exercise can help maintain brain mass, but no amount of exercise can slow the decline in cognitive abilities that is part of normal aging
Older adults who continue complex mental activities can maintain cognitive abilities, but no amount of exercise can affect brain mass