The Teenage Brain

Neuroscientist Larry Sherman, Ph.D. joined us today to talk about  teenage brain development. 

What is different about the teenage brain?
We are all born with many more brain cells than we need; these "extra" cells are actively dying off at a great rate well into the teenage years as the brain connects itself, shaped in part by experience and in part by our genes.  During the teenage years, this is accompanied by dramatic changes in brain structure especially in an area called the prefrontal cortex - an area involved in impulse control, judgement, planning and decision making.  Emotional responses are also localized to this part of the brain.

How long does this wiring and remodeling go on?
In some, these changes continue until about age 25, but some of the most serious changes occur right around puberty.

How do these changes in brain structure influence a teenagers behavior?
As we all know, teenagers ofter have issues with impulse control and judgement.  If you give car keys to a teenager, for example, they may not make the best decisions behind the wheel.  This is more than simply gaining experience with driving - it has a lot to do with the maturity of the brain.  For example, if another driver does something wrong or aggressive, the teenage brain may respond over-agressively because impulse control and emotional balance are still getting worked out.  A teenage brain is very emotional and doesn't balance rational thought with "gut feelings" very well.   The teenage brain is also more likely to throw caution to the wind, because they haven't fully developed their judgement centers.  This is why many teenagers seem to think of themselves as immune from the normal dangers that we as adults understand.

How can this information help parents understand their teenage children?
Many of the behaviors that teenagers exhibit that differ from their behaviors as young children - like increased risk taking, and looking for new stimuli - are part of the process by which the teenage brain is organizing itself as kids enter adulthood.  It is important that parents recognize these behaviors as part of growing up - but also, recognize that behaviors that look very abnormal - like depression - are not a normal part of development.

Are such abnormal behaviors of greater concern in teenagers than in adults?
They can be.  Depression, in particular, can lead to drug and alcohol abuse at very high rates in teenagers, and this gets back to the issue of impulse control and judgement.  Teenage suicide is also a great concern.  We are learning that depression in teenagers looks similar to depression in adults. But therapies in adults do not always work in teenagers.  Identifying depression in teenagers can be problematic, in that most of us have always believed that teenagers are just "naturally moody".  Also, the risk for adult depression dramatically increases if you had depression as a teenager.  So getting the right treatment is important.

Do all teenagers go through this to the same degree?
All teenage brains rewire and remodel themselves, but not everyone has the same response to this process.  The important thing to remember is that the process is transient.  Data show that the highly emotional responses to stimuli - which occur in the teenage brain predominantly in a place called the amygdala (an area involved in fear and "gut level" responses - slowly shift the to the maturing frontal lobe, leading to more reasoned responses.  We need to keep them on track to utilizing this part of their brain when making decisions and responding the situations.  If we provide them with a supportive and instructive environment, their brains will mature appropriately.

As for empathy, the question is could it be related to how teenagers have changed over the past 10 years, during a time when they have dramatically changed the way they communicate with each other and the way that they get information about the world (with the advent of texting, facebook, twitter etc.)?  During this time, children and teens were also exposed to more violence in TV and movies and on the internet.  A recent study suggested that teens in college today lack empathy compared to teens in college in the previous decades.  If true, this could have significant ramifications for our society. 

Other studies have indicated that the the teenage brain processes empathy differently from the adult brain;  this suggests that the teenage years are a critical time for the development of empathy.


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