Scientists improved the cognitive ability of adult mice by boosting the survival of newborn neurons in the brain's memory hub. Enhancing the survival of these cells, when combined with exercise, produced antidepresseant effects as well. The findings may open up new avenues for treating cognitive, mood and anxiety disorders.
Humans and many other animals rely on an important cognitive ability, known as pattern separation, to distinguish between different situations that occur in similar contexts. When this cognitive ability breaks down, a person may misread cues in the environment and perceive ordinary situations as threatening. This can happen as we age, and may also be involved in anxiety conditions such as post-traumatic stress disorder.
Previous research had shown that blocking the birth of new neurons in a part of the hippocampus, the brain's memory center, decreased pattern separation ability. Until now, however, scientists had found it difficult to selectively increase the number of young neurons in an adult animal to test whether the opposite held true.
Enter Drs. Rene Hen and Amar Sahay of Columbia University. Hen's previous work had shown that the effects of current antidepressant medications depended on the birth of new neurons, or neurogenesis, in the memory regions of the brain.