Memory Training Reduces Brain Atrophy

Numer­ous stud­ies show ben­e­fits of cog­ni­tive train­ing in old­er adults, despite a recent study ques­tion­ing their valid­i­ty. The debate on the effects of spe­cif­ic cog­ni­tive inter­ven­tions is not settled.

A find­ing that researchers do seem to agree on is that aging is accom­pa­nied by brain and cog­ni­tive decline. These reduc­tions seem to be mod­i­fi­able through cog­ni­tive and phys­i­cal exer­cise. In this vein, our lab recent­ly demon­strat­ed that old­er adults involved in an 8‑week mem­o­ry train­ing pro­gram show less brain atro­phy. This gives some hope for old­er adults won­der­ing whether their train­ing efforts are real­ly worthwhile.

A major research inter­est in our lab is how brain struc­ture and mem­o­ry change across the human life-span. We have recent­ly been able to mea­sure region­al changes in the brain with­in the same old­er adults over time. In a recent study, my super­vi­sor, Anders Fjell and col­leagues found that nor­mal aging Amer­i­cans (about 60 years old) show region­al brain atro­phy (shrink­age) of about — 0.5 – 1.0 % after only one year.

The rea­son why the brain atro­phies (shrinks in size) with age is not com­plete­ly under­stood. An old myth about aging is that we lose neu­rons as we age. This does not seem to hold true for healthy old­er adults. Instead, researchers cur­rent­ly believe that the atro­phy is more like­ly to be dri­ven by 1) nerve cells shrink­ing and 2) loss of con­nec­tions between nerve cells

Not only brain size, but also cog­ni­tive per­for­mance declines as we age. Abil­i­ties like pro­cess­ing speed and long-term mem­o­ry declines steadi­ly. How­ev­er, the pace of aging varies great­ly among old­er indi­vid­u­als. Thus, a cen­tral pur­suit in con­tem­po­rary neu­ro­science is to under­cov­er mod­i­fiers of the aging process.

Var­i­ous fac­tors are found to be asso­ci­at­ed with age-relat­ed dif­fer­ences in brain struc­ture and cog­ni­tion. Your genet­ic make­up seems to be impor­tant. Also what socioe­co­nom­ic back­ground and edu­ca­tion­al lev­el you have plays a role.

Late­ly and thor­ough­ly reviewed in the Sharp­brains blog ear­li­er, lifestyle and behav­ior seem to have a sig­nif­i­cant impact. One exam­ple is nutri­tion. In fact, David Smith and col­leagues in Oxford showed ear­li­er this fall that old­er adults with mild cog­ni­tive impair­ment have less brain atro­phy if they take a vitamin‑B sup­ple­ment regularly.

Oth­er lifestyle fac­tors con­tribut­ing to indi­vid­ual age-dif­fer­ences in both brain and cog­ni­tive func­tion are phys­i­cal and men­tal exer­cise or brain train­ing. The basis for how these influ­ence the aging process is based on the con­cept of brain plas­tic­i­ty. Brain plas­tic­i­ty is a mul­ti­fac­eted con­cept, but can be described as your brain’s abil­i­ty to change struc­tural­ly and func­tion­al­ly at any age.

In our lab we were fas­ci­nat­ed by this abil­i­ty and asked the fol­low­ing ques­tion: Could mem­o­ry train­ing impact the brain atro­phy that takes place in the aging brain? With this in mind, my research group set out to inves­ti­gate the effects of a mem­o­ry train­ing pro­gram for healthy mid­dle-aged and old­er adults (mean age = 60 years).

Through a news­pa­per add, we recruit­ed more than 40 par­tic­i­pants and divid­ed them ran­dom­ly into a mem­o­ry train­ing and con­trol group. The mem­o­ry train­ers par­tic­i­pat­ed in an 8‑week pro­gram where they learned a visu­al mnemon­ic tech­nique known as the Method of loci. Using this tech­nique the par­tic­i­pants had to learn and recall new ver­bal infor­ma­tion almost every­day, like the names of Amer­i­can pres­i­dents, Roman emper­ors, mem­bers of par­lia­ment, and the order of coun­tries in South-America.

After 8‑weeks of train­ing, we found that:

a) the mem­o­ry train­ers improved sig­nif­i­cant­ly in their abil­i­ty to remem­ber ver­bal infor­ma­tion in a par­tic­u­lar sequence (for instance the name of the 1st or 10^th Amer­i­can pres­i­dent). How­ev­er, they did not improve more on oth­er domains of mem­o­ry func­tion than the con­trol group, which is in-line with oth­er studies.

b) the thick­ness of the cere­bral cor­tex increased in sev­er­al regions of the brain among those who had trained their mem­o­ry func­tion. Also, par­tic­i­pants who had improved the most on the spe­cif­ic mem­o­ry test where the ones with the most increase in cor­ti­cal (brain) thickness.

The four regions of the brains in which mem­o­ry train­ing increased cor­ti­cal thick­ness are illus­trat­ed below. Two effects were locat­ed in the frontal lobes (lat­er­al orbitofrontal cor­tex), and one in the fusiform region of the right tem­po­ral lobe.

Fig­ure 1. The fig­ure show the strength of the effects mapped on a tem­plate brain. Top row is the right hemi­sphere in lat­er­al (from out­side), ven­tral (from under) and medi­al (from inside) views.

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The changes in cor­ti­cal thick­ness in the con­trol and train­ing groups are shown in the sec­ond fig­ure below. You can see that the con­trol group decreased slight­ly, where­as the mem­o­ry train­ers increased. Also note that the changes are small (less than 0.05 mm in most areas).

Fig­ure 2. Bar plots of the group-changes in cor­ti­cal thick­ness. The green bars are the con­trol group, the blue col­ors are the train­ing group. Lighter col­ors are the aver­age thick­ness at follow-up.

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What do these find­ings tell us? It seems as mid­dle-aged and old­er adults who train their mem­o­ry vig­or­ous­ly in a 2‑month peri­od have dif­fer­ent, more pos­i­tive changes in brain struc­ture, com­pared with those who do not. The ones who had bet­ter mem­o­ry improve­ments also had more pos­i­tive changes in the brain. The effects on mem­o­ry per­for­mance were pos­i­tive, but the trans­fer effect was seen on brain struc­ture only. We did not look at the effects beyond the 2‑months, and we are wait­ing to see whether cog­ni­tive exer­cise indeed alters the way our brains age in the long-term. Since our study was pub­lished, oth­er very recent stud­ies have shown that cog­ni­tive exer­cise in the elder­ly can also mod­i­fy the blood flow to, and the under­ly­ing nerve fibers (white mat­ter) of the frontal lobes.

Mem­o­ry train­ing improves spe­cif­ic mem­o­ry func­tions, but also seems to make pos­i­tive changes in the aging brain such as less atro­phy and even increased cor­ti­cal thick­ness. These results strength­en the con­clu­sions about the val­ue of men­tal exer­cise for old­er adults.

— Andreas Engvig was an intern at Sharp­brains a cou­ple of years ago. He is now a MD-PhD can­di­date in the Cen­ter for the Study of Human Cog­ni­tion at the Uni­ver­si­ty of Oslo, Nor­way. He is cur­rent­ly pur­su­ing his PhD inves­ti­gat­ing the effects of mem­o­ry train­ing on aging brain struc­tures. His first pub­li­ca­tion recent­ly achieved 8th place in Neu­roim­age’s “Top 25 Hottest Arti­cles” list.

Ref­er­ences

• Engvig, A., Fjell, A.M., West­lye, L.T., Mober­get, T., Sund­seth, O., Larsen, V.A., Wal­hovd, K.B., 2010. Effects of mem­o­ry train­ing on cor­ti­cal thick­ness in the elder­ly. Neu­roIm­age 52, 1667–1676.
• Engvig, A., Fjell, A.M., West­lye, L.T., Mober­get, T., Sund­seth, O., Larsen, V.A., Wal­hovd, K.B., sub­mit­ted man­u­script. Mem­o­ry train­ing impacts short-term changes in aging white matter.
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