Sharp Brains: Brain Fitness and Cognitive Health News

Neuroplasticity, Brain Fitness and Cognitive Health News

Icon

Looking inside the Brain: is my Brain Fit?

MRI scanner neuroimaging

Today we have the plea­sure to have Dr. Pas­cale Mich­e­lon, one of our new Expert Con­trib­u­tors, write her first arti­cle here. Enjoy, and please com­ment so we hear your thoughts and engage in a nice con­ver­sa­tion.

(Btw, if you notice some sim­i­lar­i­ty between the col­ors in the fMRI scan below and the look & feel of this site…well, the rea­son is that those orange-grey fMRI col­ors were our inspi­ra­tion! the orange col­or denotes the most brain acti­va­tion).

- Alvaro

————————————–

You have prob­a­bly heard about CAT and MRI scans (pro­duced thanks to machines like the one to the top right). So you know that these are tech­niques that doc­tors and sci­en­tists use to look inside the brain.

You have prob­a­bly also heard about brain fit­ness and how impor­tant it is to keep a healthy brain to be pro­tect­ed against age-relat­ed and dis­ease-relat­ed brain dam­ages.

The ques­tion we ask here is the fol­low­ing: Can we use brain scans to eval­u­ate how fit the brain is? Before we try to answer this ques­tion let’s start with the basics and try to under­stand how brain scans work.

Brain imag­ing, also called neu­roimag­ing, allows one to pro­duce images of the brain. There are dif­fer­ent types of brain imag­ing: struc­tur­al and func­tion­al. Struc­tur­al imag­ing pro­vides infor­ma­tion about the shape and vol­ume of the brain (CAT and MRI scans). Func­tion­al imag­ing shows the brain cells that are active when one per­forms a spe­cif­ic task (fMRI and PET scans).

CAT scan neuroimagingCT or CAT scans. Com­put­ed tomog­ra­phy or com­put­ed axi­al tomog­ra­phy is a tech­nique that takes a large num­ber of two-dimen­sion­al X‑rays images. These images are used to dig­i­tal­ly com­pute 3D images of the inside of the brain. The most fre­quent rea­son for a head CT is to diag­nose cere­brovas­cu­lar acci­dents and intracra­nial hem­or­rhage. It is also often use to eval­u­ate facial and skull frac­tures.

MRI scan neuroimagingMRI scans. MRI stands for Mag­net­ic Res­o­nance Imag­ing. This tech­nique uses mag­net­ic fields and radio waves to gen­er­ate 2- or 3‑D images of the brain. MRI is used to detect tumors and oth­er patholo­gies that affect the tis­sues of the brain (e.g., mul­ti­ple scle­ro­sis). Com­pared to CT, it is more pre­cise and harm­less to the patient (no poten­tial­ly dan­ger­ous X‑rays). How­ev­er, CT is much cheap­er and more wide­ly used.

PET scan neuroimagingPET scans. PET stands for Positron Emis­sion Tomog­ra­phy. It mea­sures the emis­sion gen­er­at­ed by a short-lived radioac­tive trac­er inject­ed to the patient (using the blood­stream). The 2- or 3‑D images pro­duced show brain activ­i­ty. PET is used to detect tumors and for the diag­no­sis of brain dis­eases. Since the 1990s, fMRI has sup­plant­ed PET due to its low inva­sive­ness, lack of radi­a­tion expo­sure, and rel­a­tive­ly wide avail­abil­i­ty.

fMRI scan neuroimagingfMRI scans. Func­tion­al Mag­net­ic Res­o­nance Imag­ing relies on the mag­net­ic prop­er­ties of oxy­genat­ed and deoxy­genat­ed hemo­glo­bin. This tech­nique pro­duces images of chang­ing blood flow in the brain asso­ci­at­ed with neur­al activ­i­ty. The images show the brain struc­tures acti­vat­ed dur­ing per­for­mance of dif­fer­ent tasks. fMRI is used to detect ear­ly changes in the brain fol­low­ing strokes or oth­er brain dis­eases.

What is brain reserve?

Now you know about imag­ing tech­niques. Our goal was to see whether we could use these tech­niques to eval­u­ate whether a brain is fit or not. Fit brains are brains that have what sci­en­tists call cog­ni­tive brain reserve. It is more or less the capac­i­ty of the brain to resist the expres­sion of symp­toms in the face of exist­ing neu­ropathol­o­gy. In oth­er words, peo­ple with more cog­ni­tive brain reserve can tol­er­ate more patho­log­ic changes before they show any symp­toms. If you have healthy brain, that is if you have cog­ni­tive reserve, you will still get old­er and you may still get Alzheimer dis­ease. But brain reserve will help delay­ing the effects of age and the onset of demen­tia. You may be won­der­ing: “What can I do to get some cog­ni­tive reserve? Here are 2 fac­tors that seem cru­cial:

- Edu­ca­tion (see Snow­don et al., 1989 or Katz­man, 1993)

- Lev­el of intel­lec­tu­al stim­u­la­tion (through your job or your leisure activ­i­ties) (see Scarmeas et al., 2001; Vergh­ese et al., 2003)

It looks like edu­ca­tion or intel­lec­tu­al stim­u­la­tion may increase brain reserve by increas­ing the den­si­ty of the con­nec­tions between brain cells (that is by increas­ing synaps­es between neu­rons). For more info about cog­ni­tive reserve see Alvaro inter­view with researcher Dr. Yaakov Stern.

Can you image brain reserve in the brain?

In a recent study, Perneczky and col­leagues (2006) used PET to explore the effect of cog­ni­tive reserve on Alzheimer’s dis­ease. They scanned the brain of 93 patients with mild Alzheimer’s dis­ease and 16 healthy con­trols.

It was expect­ed that peo­ple with the more severe Alzheimer’s dis­ease pathol­o­gy would show less cere­bral blood flow, that is less activ­i­ty, in the regions affect­ed by the dis­ease. Remem­ber that blood flow in the brain is what PET mea­sures.

Perneczky hypoth­e­sized that patients with more years of school­ing would have more pro­nounced deficits in regions typ­i­cal­ly affect­ed by the pathol­o­gy of Alzheimer’s dis­ease.

How could this be? Did­n’t I tell you ear­li­er that edu­ca­tion con­tributes to brain reserve?

Here is the rea­son­ing: say that Ms A. has a low lev­el of brain reserve. She has devel­oped Alzheimer’s 2 years ago. She does­n’t have much pathol­o­gy in her brain yet and her symp­toms (mem­o­ry prob­lems, etc.) cor­re­spond to a mild stage of Alzheimer’s dis­ease. Ms B. has a high lev­el of brain reserve. She has devel­oped Alzheimer’s 5 years ago. She has a high lev­el of pathol­o­gy in her brain. How­ev­er, thanks to her brain reserve, she only shows symp­toms cor­re­spond­ing to a mild stage of Alzheimer’s dis­ease.

Results of this PET study show that indeed patients with more edu­ca­tion (such as Ms B.) con­sis­tent­ly had more pro­nounced deficits in regions typ­i­cal­ly affect­ed by the pathol­o­gy of Alzheimer’s dis­ease com­pared to patients with less years of school­ing (such as Ms A.)

These find­ings sug­gest that edu­ca­tion is asso­ci­at­ed with brain reserve and that peo­ple with high­er edu­ca­tion can cope with brain dam­age for a longer time.

What if one does­n’t have high­er education…Is it too late to build cog­ni­tive brain reserve? The good news is that it is NOT too late! Edu­ca­tion is not the only fac­tor. One can always find ways to get enough men­tal stim­u­la­tion by choos­ing our jobs and engag­ing in leisure activ­i­ties such as read­ing, learn­ing new things, going to muse­ums, etc.

Pascale Michelon— This arti­cle was writ­ten by Pas­cale Mich­e­lon, Ph. D., for SharpBrains.com. Dr. Mich­e­lon has a Ph.D. in Cog­ni­tive Psy­chol­o­gy and has worked as a Research Sci­en­tist at Wash­ing­ton Uni­ver­si­ty in Saint Louis, in the Psy­chol­o­gy Depart­ment. She con­duct­ed sev­er­al research projects to under­stand how the brain makes use of visu­al infor­ma­tion and mem­o­rizes facts. She is now an Adjunct Fac­ul­ty at Wash­ing­ton Uni­ver­si­ty, and teach­es Mem­o­ry Work­shops in numer­ous retire­ment com­mu­ni­ties in the St Louis area.

Leave a Reply...

Loading Facebook Comments ...

7 Responses

  1. Joshua says:

    Real­ly look­ing inside the brain?

    The stud­ies cit­ed all use prox­ies for cog­ni­tive reserve (e.g. years of edu­ca­tion), but these indi­rect mea­sures crude­ly approx­i­mate the brain effects of such life­time expe­ri­ences. We real­ly need neu­roimag­ing tech­niques capa­ble of direct­ly mea­sur­ing the expres­sion of neur­al net­works asso­ci­at­ed with cog­ni­tive reserve. We would then be in a posi­tion to prospec­tive­ly test the effects of activ­i­ties pur­port­ed to increase reserve.

  2. Hi Joshua,
    I agree with your com­ment. Neu­ro­ge­n­e­sis and the like is real­ly hard to mea­sure in humans. Small and col­leagues (2007) used MRI to try to esti­mate the effect of phys­i­cal activ­i­ty on neu­rons for­ma­tion (which con­tributes to cog­ni­tive reserve). How­ev­er, they again used a proxy as they could not direct­ly count the new neu­rons…

  3. bennie says:

    Hi, Your arti­cle was includ­ed in the First Car­ni­val of Tech at http://www.technologymatter.com/2008/02/first-carnival-of-tech.html.
    Thanks!

  4. Chris says:

    Neu­roimag­ing is such an essen­tial part of mod­ern med­i­cine today, your web­site is bring­ing much need­ed atten­tion to this area.

  5. Alvaro says:

    Thank you, Chris!

Leave a Reply

Categories: Cognitive Neuroscience, Health & Wellness

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

About SharpBrains

As seen in The New York Times, The Wall Street Journal, BBC News, CNN, Reuters,  SharpBrains is an independent market research firm tracking how brain science can improve our health and our lives.

Search in our archives

Follow us and Engage via…

twitter_logo_header
RSS Feed

Watch All Recordings Now (40+ Speakers, 12+ Hours)