November 23, 2010
Positive Measures to Fight Depression
Time: 00:03:57 | Size: 3.65 MB
Speakers: Dr. Michael Lehmann and Dr. Robert Schloesser
Description: NIH Radio: NIMH investigators talk about new evidence that suggests exercise and positive environment can help hedge against stress related depression.
Announcer: NIH Radio from Bethesda.
Announcer: Is it possible that exercise or other positive changes to our environment can help build up resistance to stress-induced depression? Dr. Michael Lehmann is with a team of National Institute of Mental Health scientists investigating how our brains process the connection between a positive environment and fighting off depression.
Dr. Michael Lehmann: What research has shown previously is that environmental enrichment has a number of beneficial effects on the psychology and physiology of animals. [27:35] Exercise is also known to be a possible antidepressant and exercise also increases adult neurogenesis.
Announcer: Neurogenesis is the genesis of new neurons in the brain. In the late 1990s, it became apparent that new neurons are formed in the adult as well as the young brain. Teaming with Dr. Lehmann in studying the role of neurogenesis in brain function is Dr. Robert Schloesser.
Dr. Robert Schloesser: Antidepressants have to be given for like several weeks before a robust effect on neurogenesis can be detected. And it's also known in humans, antidepressants have to be given for several weeks before an antidepressant effect is being detected. And this raised the question of a connection...
Announcer: Working with mice, the NIMH scientists needed to come up with a test-something called social defeat stress- that would replicate the type of stress levels experienced by people.
Dr. Michael Lehmann: The way we set up our housing situation is that we place two male animals within the same cage but they're separated by a divider. So when we lift this divider the two animals will conflict and there will be a series of social interactions where the animals either win or lose at social interactions. The animal that continues to lose the social interactions will become behaviorally depressed.
Announcer: After 14 days, these animals were then housed either in a barren environment, or an environment with opportunities to explore and exercise. Animals housed in this enriched environment after they have undergone social defeat, stopped acting depressed. The recovery, however, depended on neurogenesis. These researchers showed this using a method involving gene transfer to shut down adult neurogenesis in some of the mice at a specific time in a specific area of the brain.
Dr. Michael Lehmann: When we knock out neurogenesis, animals that are exposed to environmental enrichment don't retain the beneficial effects of the enrichment exposure. Whereas animals that have the ability for neurogenesis are able to retain these beneficial effects.
Dr. Robert Schloesser: What's new in our study is our study is the first study that can link environmental enrichment and its beneficial effects to neurogenesis and the requirement of neurogenesis. No one had so far linked the two things that are open in the literature- that enrichment can massively increase the survival of newborn neurons and that enrichment can also has this tremendous beneficial effects on mood states and behavioral... behavior as related to mood in rodents.
Announcer: As research continues, this laboratory recently reported on studies that pinpoint an area of the brain that is central to the ability of environmental enrichment to have beneficial effects on stress resiliency. These findings suggest that this area of the brain, a part of the cortex involved in the processing of emotion, could be a target for new medications for depression.
Announcer: This is NIH radio.
See also NIMH Science Update: Novel Model of Depression from Social Defeat Shows Restorative Power of Exercise.