How Silence Regenerates the Brain

Can you remember the last time you experienced a moment of true silence? In the world we live in, silence is becoming increasingly rare. Since the mid-20th century, researchers have known that chronic noise can negatively impact health.

woman sitting in nature enjoying silenceBut in our frenzied, hyper-connected lives, taking time for silence, especially in nature, has become rare—despite that silence in nature is a key part of a healthy, plant-based lifestyle.

Silence and Brain Expansion: An “Accidental” Discovery

Much of what we know about the impact of silence on our health has been discovered accidentally. One way researchers have “accidentally” observed silence in action is through studies where silence is used as a “control” or “baseline” to assess the effect of noise or music.

Imke Kirste, a regenerative biologist at Duke University, set out to analyze the effects of sounds on the brains of adult mice—and she ended up making some extraordinary observations of how silence may expand our brains.

Kirste exposed four groups of mice to different auditory stimuli:

  • Music
  • Baby mouse calls
  • White noise
  • Silence

Going into the study, Kirste hypothesized that baby mouse calls—a form of communication—might stimulate the growth of new brain cells. Instead, she found that mice exposed to 2 hours of silence daily developed new cells in the hippocampus—a region of the brain associated with memory, emotion, and learning. Silence, which she intended to use as a baseline, had a more substantial impact that any of the sounds she had selected.

“We saw that silence is really helping the new generated cells to differentiate into neurons,” said Kirste, “and integrate into the system.” The fact that silence sparks this process, known as neurogenesis, indicates that silence could play an important role in helping the human brain rejuvenate itself.

Silent nature with glass water, mountains, and blue sky

Although her research is still in the preliminary phases, Kirste is interested in how it could be applied to conditions like dementia and depression, which are associated with decreasing rates of neurogenesis in the hippocampus. If silence leads to neurogenesis in humans, neurologists might be able to use it as a therapeutic treatment.

The Importance of “Default Mode”

Another “accidental” silence discovery came when a team of neuroscientists at Washington University looked over brain scan data from subjects conducting tasks like arithmetic and word games and found a type of background brain activity that peaked when subjects were simply sitting in silence.

Lead scientist Marcus Raichle and his team found that when subjects sat in silence with mental activity seemingly in a state of rest, their brains continued to actively internalize and evaluate information. The team defined this process as “default mode.”

Further research showed that default mode is necessary for self-reflection. According to a paper published in Frontiers in Human Neuroscience in 2013, when the brain is in this state of active recovery, it creates a “conscious workspace” that allows internal and external information to integrate. This state can be seen most frequently, wrote Joseph Moran and his co-authors, when individuals reflect on their own personalities and characteristics.  

When we pause—that is, when we temporarily halt external inputs and goal-oriented thinking—default mode takes over. These quiet periods of consciousness allow us to make sense of ourselves and to be more clear about our place in the world around us.

Quiet, Please

There’s much more to discover about the benefits of silence, but in an increasingly noisy world, there’s already evidence enough to support making space in our lives for silence. Try spending some time each day sitting in complete quiet—even five minutes can make a difference! If you prefer a more active approach, try taking a trip to a remote area where you can walk in without excessive background noise.  The important thing is to find a way that appeals to you to make space in your life for quiet.