TY - JOUR
T1 - Aging alters the multichemical networking profile of the human brain
T2 - An in vivo 1H-MRS study of young versus middle-aged subjects
AU - Grachev, Igor D.
AU - Swarnkar, Amar
AU - Szeverenyi, Nikolaus M.
AU - Ramachandran, Tarakad S.
AU - Vania Apkarian, A.
PY - 2001
Y1 - 2001
N2 - In our most recent study of normal aging, we found decreased concentration of multiple chemicals in the brain of middle-aged subjects, as compared with younger subjects using in vivo proton magnetic resonance spectroscopy (1H-MRS). We hypothesized that these age-dependent differences in brain chemistry changes might be a reflection of the multichemical-networking-profile (MCNP) changes during aging. Using 1H-MRS and correlation analysis, we examined the patterns of regional chemical levels and MCNP within and across multiple brain regions for all nine chemicals of 1H-MR spectra. The brain chemistry changes and MCNP patterns were compared between 21 young (19-31-year-old) and 31 middle-aged (40-52-year-old) normal volunteers. Middle-aged subjects demonstrated a significant decrease of chemical levels in the prefrontal cortex and sensorimotor cortex (SMC), as compared with the young age group. Of these, neurotransmitters GABA and glutamate in the dorsolateral prefrontal cortex (DLPFC) were altered the most. We also found a significant increase of overall chemical correlation strength in MCNP within and across all studied brain regions with increased age. These changes were caused by alterations in the pattern of negative chemical connectivity across brain regions, which become weaker (less negative) in middle-aged subjects. The interregional chemical connectivity for the cingulate cortex, SMC and the thalamus was changed the most with increased age. Increased levels of chemical correlation strength across brain regions in aging were found for most chemicals studied (including neurotransmitters GABA and glutamate), and not for N-acetyl aspartate. These age-related differences in the connectivity of neurotransmitters were not region dependent. The results suggest that aging is associated with changes of the regional brain chemistry and the brain MCNP. The latter process may reflect an adaptive or compensatory response (possibly related to the elongation of dendrites with aging) to reduced levels of regional brain chemicals. The 1H-MRS approach proposed here can be used as a valuable tool in the study of the brain chemistry, MCNP and their relationships in normal and abnormal aging.
AB - In our most recent study of normal aging, we found decreased concentration of multiple chemicals in the brain of middle-aged subjects, as compared with younger subjects using in vivo proton magnetic resonance spectroscopy (1H-MRS). We hypothesized that these age-dependent differences in brain chemistry changes might be a reflection of the multichemical-networking-profile (MCNP) changes during aging. Using 1H-MRS and correlation analysis, we examined the patterns of regional chemical levels and MCNP within and across multiple brain regions for all nine chemicals of 1H-MR spectra. The brain chemistry changes and MCNP patterns were compared between 21 young (19-31-year-old) and 31 middle-aged (40-52-year-old) normal volunteers. Middle-aged subjects demonstrated a significant decrease of chemical levels in the prefrontal cortex and sensorimotor cortex (SMC), as compared with the young age group. Of these, neurotransmitters GABA and glutamate in the dorsolateral prefrontal cortex (DLPFC) were altered the most. We also found a significant increase of overall chemical correlation strength in MCNP within and across all studied brain regions with increased age. These changes were caused by alterations in the pattern of negative chemical connectivity across brain regions, which become weaker (less negative) in middle-aged subjects. The interregional chemical connectivity for the cingulate cortex, SMC and the thalamus was changed the most with increased age. Increased levels of chemical correlation strength across brain regions in aging were found for most chemicals studied (including neurotransmitters GABA and glutamate), and not for N-acetyl aspartate. These age-related differences in the connectivity of neurotransmitters were not region dependent. The results suggest that aging is associated with changes of the regional brain chemistry and the brain MCNP. The latter process may reflect an adaptive or compensatory response (possibly related to the elongation of dendrites with aging) to reduced levels of regional brain chemicals. The 1H-MRS approach proposed here can be used as a valuable tool in the study of the brain chemistry, MCNP and their relationships in normal and abnormal aging.
KW - Aging
KW - Human brain
KW - Multichemical networking profile
KW - Proton magnetic resonance spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=0035077319&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035077319&partnerID=8YFLogxK
U2 - 10.1046/j.1471-4159.2001.00238.x
DO - 10.1046/j.1471-4159.2001.00238.x
M3 - Article
C2 - 11279285
AN - SCOPUS:0035077319
SN - 0022-3042
VL - 77
SP - 292
EP - 303
JO - Journal of neurochemistry
JF - Journal of neurochemistry
IS - 1
ER -