Effect of aging on olfaction center function: a magnetic resonance imaging study / 中华老年医学杂志

ABSTRACT

Objective To investigate the localization,zone and activation intensity of olfactory center in young versus elderly healthy volunteers by functional magnetic resonance imaging (BOLD-fMRI),so as to elucidate the effect of age on olfactory center in healthy population.Methods Thirteen right-handed healthy adult volunteers were recruited and divided into two groupsyoung group (5 males and 3 females,mean aged 23 years) and elderly group (2 males and 3 females,mean aged 69.2 years).The olfactory stimulus was r-undecalactone,and it was given according to a block design.The fMRI detection was performed on Philips Achieva 3.0 T MR scanner,and data of BOLE-fMRI was processed and analyzed to get cerebration image by using SPM2.Results In groupaveraged maps,both young and elderly group showed significant olfactory activation in right parahippocampal gyrus,left hippocampal sulcus,right and left superior temporal gyrus,etc,subcortical activation in right thalamus,dorsal pons,and cerebellum activation in cerebellar vermis.Activations in right inferior frontal gyrus,right middle frontal gyrus,right medial occipito-temporal gyrus and right fimbria of hippocampus were observed only in young group,while activation in bilateral middle temporal gyrus was observed only in elderly group.Activation area was apparently smaller and activation degree was lower in elderly group than in young group.Activation intensity in right superior parietal lobule and bilateral superior temporal gyri was higher in male group than in female group (t=13.7,6.08,5.36,respectively,all P＜0.001).Conclusions The intensity of activation in olfactory center is lower in the elderly than in the young,and absence of part of the active regions is found in the elderly,which demonstrates the regression of olfactory center in the elderly.The olfactory center shows right-predominant activation,and olfactory activation intensity in some cortical regions is higher in males than in females.