By Lisa M. Belisle, MD, MPH
Medical Advisor, Raising Readers
Raising Readers Issue Brief, Spring 2007

“THWACK!!” Without warning, the neurology professor cracked a yardstick on the podium. I (along with the majority of the medical students in class with me) jumped in my seat, startled out of my lecture-induced reverie. The professor made his point—that fear and learning are intricately connected in the mammalian brain. Years later I still recall the vivid demonstration of this fact.

The interplay between fear and learning begins with two ancient (evolutionarily speaking) structures in the brain: the hippocampus and the amygdala. The amygdala alerts us to danger, enables us to create memories, and facilitates the transfer of information to the associative cortex for later retrieval. The hippocampus inhibits the amygdala, and its fear response.

While some fear and related stress can enhance learning potential (think ruler-wielding professors), too much can be detrimental. The hippocampus is very sensitive to chemical changes in the body. It reacts readily to alterations in oxygen tension and blood glucose caused by physiologic stressors. Studies have shown that long term stressors can increase the brain’s vulnerability to depression by causing changes to the structure and volume of the hippocampus. Changes to the hippocampus can interfere with the amygdala’s fear response, and make learning difficult.

The relationship between learning, stress and fear is especially important in early childhood. Individuals typically associate fear with events that are dangerous or intimidating, or those in which they lack control. Children often find themselves lacking control. They are regularly exposed to new experiences, such as the arrival of a sibling or the introduction of a preschool classroom.

To counteract the inherent uncertainty of new experiences, children depend on stable relationships with their caregivers. This is has been called “attachment” in the field of psychology. Having secure attachments gives children an important home base from which they can explore the external world and make independent decisions: having secure attachments enables children to learn.

While attachment describes the impact of the human connection on a psychological level, there is evidence that this connection has ramifications on a physiologic level as well. This idea has been the focus of work done by Dr. Gregory Fricchione, Director of the Benson-Henry Institute for Mind-Body Medicine. Dr. Fricchione has labeled the physiologic relationship between individuals “attunement.”

At the 2006 Harvard conference on Spirituality and Healing in Medicine, Dr. Fricchione discussed attunement using examples from the scientific literature. In one study (done by Epel et al, at UCSF), researchers examined the lymphocytes of mothers with chronically ill children. Compared to normal controls, the lymphocyte chromosomes were significantly less able to engage in self-repair. Lymphocytes from the test group lost 600 telomere base pairs a year (only 55 base pairs a year are lost with normal aging). The long-term stress in the lives of these mothers was clearly having a detrimental effect on their health.

In contrast to the negative physiologic effects stemming from a stressful relationship are the beneficial physiologic effects of a positive relationship. To demonstrate this, Dr. Fricchione cited a study which focused on rats and their babies. This study (done by Weaver, et al, at McGill University) found that rats with highly “nurturant” mothers became more able to withstand stress than those with less nurturant mothers. The former group had alterations in gene activation, and subsequent positive changes in hippocampal functioning. These rats exhibited a greater resiliency and ability to deal with stressors.

Whether we are describing rats or humans, it is apparent that relationships impact our stress management skills. Childhood attachment is only the beginning. People who have social contacts are more likely to survive chronic illnesses, or traumas such as heart attacks. Men who are married live longer than those who aren’t. Obviously there are advantages to attunement.

Attunement and attachment are two different ways to describe one very important concept: animals are social creatures. We need one another both to learn and to live. We also need one another to keep us from feeling foolish, as we all jump out of our seats in response to our neurology professor’s loud ruler “THWACK!!”

Research assistance provided by Kate Bartley.

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RESOURCES:

Proceeds from Spirituality & Healing in Medicine, December 2-3, 2006, Boston, MA.