Most everyone can relate to being stressed out. But, how does stress actually affect us and our brains? A recent talk gave an in-depth look at the neuroscience involved with various types of stress. And, while this may not convince everyone’s employer to let them take the day off and head to the beach, the research will likely lead to better understanding of and therapy for stress-related conditions.
Dr. Daniela Kaufer, a UC Berkeley associate professor of integrative biology, gave a lecture April 3rd at Berkeley’s Pyramid Alehouse. She discussed the dangers that certain types of stress pose to the brain and suggested some mechanisms behind this and new directions for treatment.
Her work focuses on the neurobiology behind brain plasticity, the ability the brain has to develop new neural pathways as we learn and experience new things. Researchers are just beginning to study and understand plasticity and how it can allow the brain to recover to an extent from injury and trauma.
Dr. Kaufer explained that only ten percent of brain cells are neurons. What we commonly consider a ‘brain cell,’ neurons facilitate the transmission of electrical impulses that enable us to recognize and respond to stimuli from the environment. The remaining brain cells are known as glia, and consist of oligodendrocytes, which produce the myelin sheath that coats our nerve cells and facilitates impulse transmission, astrocytes, which might provide support, and microglia, which are a kind of immune system for the brain.
A central dogma of neuroscience is that neurons can die, but don’t regenerate. However, modern science suggests a much greater degree of cell remodeling may occur than we thought possible. Some birds learn a new song each season, and this level of learning, as Kaufer said, depends on new neuron generation.
Dr. Kaufer’s lab has shown that cells within the dentate gyrus, a thin layer of stem cells within the hippocampus, a brain area involved in memory and learning, can continue to develop and differentiate into neurons and glial cells. These cells become selectively activated during learning tasks involving spatial memory and pattern discrimination.
Her research also points to a mechanism behind the onset of post-traumatic epilepsy in some patients with severe brain injuries. In epilepsy, large areas of a person’s brain cells stop their normal signaling patterns and all fire in synchronized waves, bringing about a seizure that can last for several seconds to a minute.
Normally, most substances in the blood don’t pass into or affect the brain. Alcohol and other drugs do, which is why they have effects on the nervous system, but most of what we eat or consume doesn’t cross the blood-brain barrier. However, serious brain injuries, inflammation, and severe stress can all damage the blood-brain barrier and all can lead to epilepsy.
Laboratory observations showed that the development of epilepsy correlates with uptake of a small protein called albumen by the brain’s astrocyte glia cells. When the albumen entered, the astrocytes turned off their potassium buffering cells, making their synapses more excitable, which led to the firing patterns associated with epilepsy.
Researchers would like to have a drug that can block the signaling patterns brought about by the albumen uptake. So far, the blood pressure medicine Losaran has a side effect of doing this, on top of reducing hypertension, and is being tested.
Stress from other sources other than head trauma, such as being busy or dealing with complex situations, can lead to impaired memory and problems with executive function, the brain’s ability to plan and organize information and make decisions. An optimal level of stress has been shown to enhance cognitive performance, but too much causes problems.
Factors such as sex, learning, exercise, environmental enrichment, and antidepressants all promote the generation of new cells in the hippocampus, and may help the brain recover from everyday stress. Alcohol, jet lag, normal aging, and inflammation inhibit hippocampal cell development.
Glucocorticoids, a class of hormones associated with the body’s stress response, inhibit neuron production. Stress leads to fewer neurons and more oligodendrocyte cells in the brain, and a change in myelination. Neurons are coated with an insulating layer of myelin, a substance made of protein and fats, and having too much or too little myelin around the cells can lead to neurological and psychological problems.
Dr. Kaufer closed her talk by pointing out that unhealthy levels of stress and trauma during childhood, whether from injury or from serious life challenges, was linked to a greater risk of developing mental illness. When asked about interventions that might help children and teens living through stress, she replied that neurologists and psychiatrists were actively researching possible therapies of this type.
Note: For more practical information on strategies you can use to regulate your stress response and manage your moods naturally, please check out Dr. Loretta Breuning’s books Meet Your Happy Chemicals and Beyond Cynical. She’s a retired management professor and zoo docent who believes we as humans can learn a lot from observing our fellow mammals.