The effect of age on the homotopic motor cortical long-term potentiation-like effect induced by quadripulse stimulation

Ritsuko Hanajima, Nobuyuki Tanaka, Ryosuke Tsutsumi, Hiroyuki Enomoto, Mitsunari Abe, Koichiro Nakamura, Shunsuke Kobayashi, Masashi Hamada, Takahiro Shimizu, Yasuo Terao, Yoshikazu Ugawa

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)2103-2108
Number of pages6
JournalExperimental Brain Research
Volume235
Issue number7
DOIs
Publication statusPublished - 2017 Jul 1

Keywords

  • Age dependence
  • Cortical plasticity
  • Transcranial magnetic stimulation
  • Variability

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'The effect of age on the homotopic motor cortical long-term potentiation-like effect induced by quadripulse stimulation'. Together they form a unique fingerprint.

Cite this