TY - JOUR
T1 - Age-related changes in short-latency motor cortex inhibition
AU - Smith, Ashleigh E.
AU - Ridding, Michael C.
AU - Higgins, Ryan D.
AU - Wittert, Gary A.
AU - Pitcher, Julia B.
N1 - Funding Information:
Acknowledgments We thank Mr. Sean Martin and the members of the Florey Adelaide Male Ageing Study for their assistance and participation. This work was funded by the National Health and Medical Research Council (NH&MRC) of Australia. AES is a South Australian Department of Health/Faculty of Health Sciences Scholar. JBP is an NH&MRC Peter Doherty Research Fellow. MCR is an NH&MRC Senior Research Fellow.
PY - 2009/10
Y1 - 2009/10
N2 - This study examined whether short-latency intracortical inhibition (SICI) and/or facilitation (ICF) changes with ageing, and if this can be attributed to age-related changes in the inhibition and/or corticospinal stimulus-response curves. SICI/ICF was studied in 17 "old" (63.1 ± 4.2 years) and 13 "young" males (20.0 ± 2.0 years) in both hemispheres using a paired-pulse transcranial magnetic stimulation paradigm at four interstimulus intervals (1, 3, 10 and 12 ms). Motor-evoked potentials were recorded from the first dorsal interosseous muscle at rest, with a conditioning intensity set at 5% stimulator output below the active threshold (aMT). Regardless of age, SICI was greater in the left compared with the right hemisphere. SICI was increased in old men at 3 ms in the left hemisphere and at 1 ms in the in both hemispheres, but ICF was not altered. However, aMT, and hence the conditioning stimulus intensity, was higher in old men. Comparisons of pairs of young and old men with the same aMT, and of SICI curves constructed relative to aMT, failed to show any age-related increase in SICI, although age-related changes in aMT accounted for less than 20% of the variability. Corticospinal stimulus-response characteristics did not influence SICI/ICF and appear not to be altered by ageing in men. When measured in resting muscles, SICI/ICF appears unaltered by age. But it remains unknown if, when assessed during movement preparation or movement, there are changes in SICI related to functional motor changes commonly associated with ageing, such as slowing of movement.
AB - This study examined whether short-latency intracortical inhibition (SICI) and/or facilitation (ICF) changes with ageing, and if this can be attributed to age-related changes in the inhibition and/or corticospinal stimulus-response curves. SICI/ICF was studied in 17 "old" (63.1 ± 4.2 years) and 13 "young" males (20.0 ± 2.0 years) in both hemispheres using a paired-pulse transcranial magnetic stimulation paradigm at four interstimulus intervals (1, 3, 10 and 12 ms). Motor-evoked potentials were recorded from the first dorsal interosseous muscle at rest, with a conditioning intensity set at 5% stimulator output below the active threshold (aMT). Regardless of age, SICI was greater in the left compared with the right hemisphere. SICI was increased in old men at 3 ms in the left hemisphere and at 1 ms in the in both hemispheres, but ICF was not altered. However, aMT, and hence the conditioning stimulus intensity, was higher in old men. Comparisons of pairs of young and old men with the same aMT, and of SICI curves constructed relative to aMT, failed to show any age-related increase in SICI, although age-related changes in aMT accounted for less than 20% of the variability. Corticospinal stimulus-response characteristics did not influence SICI/ICF and appear not to be altered by ageing in men. When measured in resting muscles, SICI/ICF appears unaltered by age. But it remains unknown if, when assessed during movement preparation or movement, there are changes in SICI related to functional motor changes commonly associated with ageing, such as slowing of movement.
KW - Florey Adelaide Male Ageing Study
KW - Motor cortex
KW - Transcranial magnetic stimulation
UR - http://www.scopus.com/inward/record.url?scp=70349229219&partnerID=8YFLogxK
U2 - 10.1007/s00221-009-1945-8
DO - 10.1007/s00221-009-1945-8
M3 - Article
C2 - 19618169
AN - SCOPUS:70349229219
SN - 0014-4819
VL - 198
SP - 489
EP - 500
JO - Experimental Brain Research
JF - Experimental Brain Research
IS - 4
ER -