Mighty Dons Of Science News

In a study that could help clar­i­fy the com­plex rela­t­ion­ships be­tween the brain, en­vi­ron­ment and be­hav­ior, re­search­ers have found that four-month-old in­fants’ tem­per­a­ment pre­dicts some as­pects of their brain struc­ture 18 years lat­er.

Sci­en­tists at Mas­sa­chu­setts Gen­er­al Hos­pi­tal in Charles­town, Mass., stud­ied 76 eighteen-year-olds that, at four months of age, had been cat­e­go­rized in pre­vi­ous re­search as “high-reac­tive” or “low-reac­tive.” High-reac­tive gen­er­ally means shy and in­hib­ited, while low-reac­tive means out­go­ing and un­in­hib­ited.

The in­ves­ti­ga­tors used a form of brain scan­ning known as struc­tur­al mag­net­ic res­o­nance im­ag­ing, which em­ploys mag­net­ic field and ra­di­o waves to pro­duce clear and de­tailed pic­tures of the brain.

Adults with a low-reac­tive in­fant tem­per­a­ment showed great­er thick­ness in a brain struc­ture called the left or­bitofrontal cor­tex, the sci­en­tists found. This re­gion has been im­pli­cat­ed in pro­cess­ing of emo­tions and of self-monitoring.

On the oth­er hand, the adults pre­vi­ously cat­e­go­rized as high-reac­tive, showed great­er thick­ness in the right ven­tro­me­dial pre­fron­tal cor­tex, the re­search­ers re­ported. This brain ar­ea has been linked to im­pulse con­trol, with great­er size linked to more self-con­trol, and with the anal­y­sis of so­cial situa­t­ions.

“To our knowl­edge, this is the first demon­stra­t­ion that tem­per­a­mental dif­fer­ences meas­ured at four months of age have im­plica­t­ions for the ar­chi­tec­ture of hu­man cer­e­bral cor­tex last­ing in­to adult­hood,” the re­search­ers wrote in the stu­dy, pub­lished in the Jan­u­ary is­sue of the jour­nal Ar­chives of Gen­er­al Psy­chi­a­try. The cer­e­bral cor­tex is a lay­er of brain cells cov­er­ing the sur­face of the brain and linked to ad­vanced think­ing func­tions.

High-reac­tive in­fants are char­ac­ter­ized at age four months by vig­or­ous ac­ti­vity and cry­ing in re­sponse to un­fa­mil­iar stim­u­li, ac­cord­ing to the au­thors, Carl Schwartz, di­rec­tor of the hos­pi­tal’s De­vel­op­men­tal Neuroim­ag­ing and Psy­cho­pa­thol&sh Re­search Lab­o­r­a­to­ry, and col­leagues. Low-reac­tive in­fants by con­trast stay more still and cry less in re­spose to the same situa­t­ions.

High-reac­tive in­fants tend to be­come be­hav­iorally in­hib­ited in the sec­ond year of life, while low-reac­tive in­fants tend the op­po­site way, the au­thors added.