TY - JOUR
T1 - The effect of age on the homotopic motor cortical long-term potentiation-like effect induced by quadripulse stimulation
AU - Hanajima, Ritsuko
AU - Tanaka, Nobuyuki
AU - Tsutsumi, Ryosuke
AU - Enomoto, Hiroyuki
AU - Abe, Mitsunari
AU - Nakamura, Koichiro
AU - Kobayashi, Shunsuke
AU - Hamada, Masashi
AU - Shimizu, Takahiro
AU - Terao, Yasuo
AU - Ugawa, Yoshikazu
N1 - Funding Information:
This work was supported in part by a research grant from Catecholamine and the Neurological Disorders Symposium (RH), research funds from the Magnetic Health Science Foundation (RH, YT) and by research grants from Research Project Grant-in-aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology [No. 26461308 (RH), No. 25293206 (YU), No. 22390181 (YU, HE), No. 25461322 (HE), No. 22590954 (YT), 15K19496 (RT), 15H05881 (RH, YU), 16H05322 (YU),15H01658 (MH), 15K19476 (MH), and 16H01605 (MH)].
Publisher Copyright:
© 2017, Springer-Verlag Berlin Heidelberg.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - The reduction of plasticity with age has been shown by many previous papers in animal experiments. This issue can be studied in humans because several non-invasive brain stimulation techniques induce synaptic plasticity in the human brain. We investigated the influence of individuals’ age on the responder rate of the long-term potentiation (LTP)-like effect induced by quadripulse magnetic stimulation (QPS). The participants were 107 healthy volunteers: 53 older participants (Mean ± SD 65.0 ± 1.5 years) and 54 younger participants (37.2 ± 8.7). The quadripulse stimulation with 5-ms inter-pulse interval (QPS5) was applied over the primary motor cortex (M1). We measured motor evoked potentials (MEPs) before QPS, and at five time points after QPS for up to 25 min. In each participant, average MEP amplitude (size) ratios were quantified. We first classified participants as responders and non-responders simply by comparing the size ratio with 1.0 for consistency with previous studies, then as “significant responders”, “non-responders”, and “opposite responders” for more detailed analysis by comparing the size ratio with the mean and standard deviation of the MEP size ratios of the sham condition. The degree of LTP-like effects induced by QPS5 was significantly smaller in the older group compared to the younger group. Also, the rates of responders and significant responders were lower in the older group (58 and 47%, respectively) compared to the younger group (80 and 76%, respectively). The age of the participants significantly affected the LTP-like effect induced by QPS5, which suggests that brain plasticity decreases with age.
AB - The reduction of plasticity with age has been shown by many previous papers in animal experiments. This issue can be studied in humans because several non-invasive brain stimulation techniques induce synaptic plasticity in the human brain. We investigated the influence of individuals’ age on the responder rate of the long-term potentiation (LTP)-like effect induced by quadripulse magnetic stimulation (QPS). The participants were 107 healthy volunteers: 53 older participants (Mean ± SD 65.0 ± 1.5 years) and 54 younger participants (37.2 ± 8.7). The quadripulse stimulation with 5-ms inter-pulse interval (QPS5) was applied over the primary motor cortex (M1). We measured motor evoked potentials (MEPs) before QPS, and at five time points after QPS for up to 25 min. In each participant, average MEP amplitude (size) ratios were quantified. We first classified participants as responders and non-responders simply by comparing the size ratio with 1.0 for consistency with previous studies, then as “significant responders”, “non-responders”, and “opposite responders” for more detailed analysis by comparing the size ratio with the mean and standard deviation of the MEP size ratios of the sham condition. The degree of LTP-like effects induced by QPS5 was significantly smaller in the older group compared to the younger group. Also, the rates of responders and significant responders were lower in the older group (58 and 47%, respectively) compared to the younger group (80 and 76%, respectively). The age of the participants significantly affected the LTP-like effect induced by QPS5, which suggests that brain plasticity decreases with age.
KW - Age dependence
KW - Cortical plasticity
KW - Transcranial magnetic stimulation
KW - Variability
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U2 - 10.1007/s00221-017-4953-0
DO - 10.1007/s00221-017-4953-0
M3 - Article
AN - SCOPUS:85017174688
VL - 235
SP - 2103
EP - 2108
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 7
ER -
