Sharp Brains: Brain Fitness and Cognitive Health News

Neuroplasticity, Brain Fitness and Cognitive Health News


Stress and Neural Wreckage: Part of the Brain Plasticity Puzzle

Victoria Crater MarsEditor’s Note: Below you have a very insight­ful arti­cle on stress by Gre­go­ry Kel­let, a researcher at UCSF. Enjoy!


My brain is fried, toast, fraz­zled, burnt out. How many times have you said or heard one ver­sion or anoth­er of these state­ments. Most of us think we are being fig­u­ra­tive when we utter such phras­es, but research shows that the bio­log­i­cal con­se­quences of sus­tained high lev­els of stress may have us being more accu­rate than we would like to think.

Crash Course on Stress

Our bod­ies are a com­plex bal­anc­ing act between sys­tems work­ing full time to keep us alive and well. This bal­anc­ing act is con­stant­ly adapt­ing to the myr­i­ad of changes occur­ring every sec­ond with­in our­selves and our envi­ron­ments. When it gets dark our pupils dilate, when we get hot we sweat, when we smell food we sali­vate, and so forth. This con­stant bal­anc­ing act main­tains a range of sta­bil­i­ty in the body via change; and is often referred to as allosta­sis. Any change which threat­ens this bal­ance can be referred to as allo­sta­t­ic load or stress.

Allo­sta­t­ic load/stress is part of being alive. For exam­ple just by get­ting up in the morn­ing, we all expe­ri­ence a very impor­tant need to increase our heart rate and blood pres­sure in order to feed our new­ly ele­vat­ed brain. Although usu­al­ly man­age­able, this is a change which the body needs to adapt to and, by our def­i­n­i­tion, a stres­sor.

Stress is only a prob­lem when this allo­sta­t­ic load becomes over­load. When change is exces­sive or our abil­i­ty to adapt is com­pro­mised, things start to go wrong. We will focus here on what seems to be hap­pen­ing in the brain under such con­di­tions.

Ener­gy Mobi­liza­tion

Whether it’s get­ting up in the morn­ing, wor­ry­ing about the non-exis­tent past/future, or get­ting angry at your last park­ing tick­et, stress takes ener­gy. One of the major roles of the infa­mous fight or flight response is to mobi­lize ener­gy, and it does this well. If you need to run away from a swarm of killer bees or fend off an attack­ing bear, you will be assist­ed by var­i­ous chem­i­cals pro­duced with­in the body. These include the well-known adrenaline–now more com­mon­ly referred to as epinephrine–and a less­er known group of chem­i­cals known as the glu­co­cor­ti­coids, most notably cor­ti­sol. Both epi­neph­rine and the glu­co­cor­ti­coids are involved in mak­ing stored ener­gy avail­able for use in the form of fats and sug­ars. Epi­neph­rine does so over the short term (with­in sec­onds) while glu­co­cor­ti­coids act over a longer peri­od (min­utes to hours). Let’s look at the effects of the lat­er of the two, the glu­co­cor­ti­coids.

Your Brain on Stress

Cor­ti­sol, the most promi­nent of the glu­co­cor­ti­coids, does an excel­lent job of allow­ing us to adapt to most stres­sors which last more than a cou­ple of min­utes but under an hour. Short term it will actu­al­ly enhance our immune sys­tem, mem­o­ry and atten­tion. Long term, past ½ hour to an hour, exces­sive­ly ele­vat­ed cor­ti­sol lev­els start to have detri­men­tal effects. It seems we were designed more to deal with short spurts of high stress, such as beat­ing back that attack­ing bear, rather than long drawn-out stres­sors such as meet­ing dead­lines.

Our brains appear to be most vul­ner­a­ble to the effects of exces­sive stress in a region called the hip­pocam­pus. The hip­pocam­pus is a mass of neu­rons each with mul­ti­ple branch-like exten­sions (den­drites and axons) which make con­nec­tions (synaps­es) with oth­er neu­rons all across the brain. Among oth­er things, this region is impor­tant in deal­ing with emo­tions and con­sol­i­dat­ing new mem­o­ries. As with all brain regions, its abil­i­ty to adapt relies upon being able to alter the branch­ing and con­nec­tions of its neu­rons. The hip­pocam­pus is also one of the only regions of the brain known to be able to pro­duce new neu­rons, a process called neu­ro­ge­n­e­sis.

Brain Dam­age

Endur­ing a high stres­sor for more than 30 min­utes to an hour has been shown to neg­a­tive­ly impact the hip­pocam­pus in var­i­ous ways. To begin, sus­tained expo­sure to high­er than nor­mal lev­els of cor­ti­sol results in the prun­ing back of the num­ber of branch­es and synap­tic con­nec­tions of hip­pocam­pal neu­rons. By a vari­ety of mech­a­nisms, these con­di­tions also increase the rate of cell death in this region of the brain.

As if this wasn’t bad enough, recent research is also demon­strat­ing that sus­tained increas­es in glu­co­cor­ti­coid lev­els also has neg­a­tive effects, impair­ing the hippocampus’s abil­i­ty to cre­ate new neu­rons.

Over a peri­od of time, all of this results in the shrink­ing in size of the hip­pocam­pus with asso­ci­at­ed declines in cog­ni­tive func­tion, includ­ing the abil­i­ty to retain new infor­ma­tion and adapt to nov­el sit­u­a­tions.

Dam­age Con­trol

For­tu­nate­ly the neg­a­tive effects of exces­sive stress can not only be stopped but also reversed once the source (psy­cho­log­i­cal or phys­i­cal) is removed or suf­fi­cient­ly reduced. Next time we will explore tech­niques one can use to pro­tect our brains by man­ag­ing the unavoid­able stres­sors we all face as part of being human.

Gregory Kellet on stress management— Gre­go­ry Kel­lett has a mas­ters in Cog­ni­tive Neurology/Research Psy­chol­o­gy from SFSU and is a researcher at UCSF where he cur­rent­ly inves­ti­gates the psy­chophys­i­ol­o­gy of social stress.


Leave a Reply...

Loading Facebook Comments ...

11 Responses

  1. Gigi Aelbers says:

    Great arti­cle. Reads well and is very clear, even if you’re not a sci­ence major.

  2. Alvaro says:

    Hel­lo Gigi, glad you enjoyed it. I do think Gre­go­ry did an amaz­ing job at explain­ing such a com­plex top­ic.

  3. Michelle B says:

    Excel­lent article–especially appre­ci­at­ed the con­nec­tion made between stress and using of ener­gy via par­tic­u­lar hor­mones which if remain ele­vat­ed exert neg­a­tive effects on a spe­cif­ic brain region.

  4. Gregory says:

    Thanks for the kudos,

    Yeah I find it intrigu­ing that we are actu­al­ly designed to han­dle most acute stres­sors quite well,…if not the exces­sive, longterm vari­ety.

  5. mig says:

    the best part of this is that if we make a change now in the way we han­dle our stress the neg­a­tive effects can be reversed. Cool. I’m going to go chill out now.

  6. Alvaro says:

    hel­lo Mig, it is not clear if every­thing can be ful­ly “reversed”, but as Gre­go­ry points out there is much we can do today, tomor­row, next week…to help main­tain our brains.

  7. Pat says:

    Great arti­cle. I lost all my beau­ti­ful thick long hair about 20 years ago, all due to stress. I do every­thing I can do now dur­ing stress­ful times to eat right, take vit­a­mins, and get plen­ty of exer­cise. (Blog­ging helps me too!)

  8. ron mack says:

    This is a fan­tas­tic arti­cle that goes a long way in help­ing me to real­ize why I have been for­get­ting things so often! Valu­able!

  9. Being in my mid 80’s I am very con­scious of memory/nonmemory. This arti­cle gives me some insight in improv­ing the for­mer and reduc­ing the lat­ter.

  10. Rajni says:

    I have seen clear­ly the neg­a­tive effects of stress on mem­o­ry, deci­sion mak­ing and act­ing ratio­nal­ly. Your descrip­tion of neu­ro­ge­n­e­sis and how it gets effect­ed by long term stress explains it all very clear­ly.

Leave a Reply

Categories: Cognitive Neuroscience, Health & Wellness, Peak Performance

Tags: , , , , , , , , , , , , , , , , , , , , , ,

All Slidedecks & Recordings Available — click image below

Search for anything brain-related in our article archives

About SharpBrains

As seen in The New York Times, The Wall Street Journal, BBC News, CNN, Reuters, and more, SharpBrains is an independent market research firm and think tank tracking health and performance applications of brain science.