Depression Physically Changes Your Brain, Scientists Discover
A recent Australian study found that depression may hinder neuroplasticity. Researchers measured electrical changes in the brain of 23 depressed and 23 healthy people after a brief magnetic stimulation. They found the expected change and reaction in the brains of healthy people, but not in the depressed.
Neuroplasticity is the reason why at first your trumpet skills in middle school were terrible, but after a few weeks of training, you got the hang of it, and by the end of the year recital you had a solo.
It is the remarkable ability of our brains to change and adapt from experience. Neurons form connections in the brain when we learn something new. As we become proficient, these pathways are strengthened, and the task becomes easier. The structure of your brain changes, and it is molded based on your experiences.
However, this notion is a recent discovery. Santiago Ramón y Cajal, a founding father of neuroscience, believed that nerve pathways were fixed and permanent. For most of the 20th century, this was the accepted view. Lucky for us, Cajal was wrong, and we now know that the brain remains dynamic throughout our lives.
Neuroplasticity is not only a central tenet to learning and memory, but also has implications for recovery. For example, when stroke damage kills neurons in one area of the brain, neurons from other regions can step in and make new pathways to recover lost function. In addition, cognitive behavioral therapy (CBT), a treatment for brain disorders such as depression, teaches patients to identify and change negative thoughts. It has been shown to alter neural pathways to support positive thinking patterns in depressed patients. So although treatments such as CBT may eventually lead to neural changes, as the new Australian study shows, depression may make those changes harder to achieve.
Neuroplasticity can also be harnessed to improve cognitive function. Brain training games like Lumosity use novel exercises to strengthen functions like remembering names, attention, and multitasking. The games get more difficult as you continue to play, which challenges the brain to find new ways to solve problems and ultimately improve neural pathways. Recently, researchers found that using Lumosity improved cognitive function in cancer patients that received chemotherapy. "Chemo-brain" may be a side effect of chemotherapy treatment, with symptoms including cloudy thinking and slow working memory. This study suggests the benefits of brain training can transfer into daily life.
Finally, like brain disorders, drugs and drug abuse can affect neuroplasticity. Recently, researchers from the University of Washington found that repeated exposure to amphetamine effects long-lasting presynaptic plasticity in the dorsal striatum, an area of the brain associated with reward and decision-making. They showed that acetylcholine, a chemical that is increased with amphetamine use, may modulate glutamatergic synapses. Glutamate, an important neurotransmitter for learning and memory, is thought to also play a role in withdrawal symptoms from drug abuse. Mice with reduced acetylcholine exhibited cognitive inflexibility, such as impaired motor coordination and exploratory behaviors. The researchers suggested alternative withdrawal treatments that act on these acetylcholine pathways.
Neuroplasticity is a life long property of the brain. We've seen the influence training, drugs, and the environment can have on your neurons. Looks like you can teach an old dog new tricks.