Experimental Brain Research

, Volume 218, Issue 1, pp 21–26

Reduced interhemispheric inhibition in mild cognitive impairment

  • Ryosuke Tsutsumi
  • Ritsuko Hanajima
  • Masashi Hamada
  • Yuichiro Shirota
  • Hideyuki Matsumoto
  • Yasuo Terao
  • Shinya Ohminami
  • Yoshihiro Yamakawa
  • Hiroyuki Shimada
  • Shoji Tsuji
  • Yoshikazu Ugawa
Research Article

DOI: 10.1007/s00221-011-2997-0

Cite this article as:
Tsutsumi, R., Hanajima, R., Hamada, M. et al. Exp Brain Res (2012) 218: 21. doi:10.1007/s00221-011-2997-0

Abstract

In mild cognitive impairment (MCI), the corpus callosum is known to be affected structurally. We evaluated callosal function by interhemispheric inhibition (IHI) using transcranial magnetic stimulation (TMS) in MCI patients. We investigated 12 amnestic MCI patients and 16 healthy age-matched control subjects. The IHI was studied with a paired-pulse TMS technique. The conditioning TMS was given over the right primary motor cortex (M1) and the test TMS over the left M1. Motor evoked potentials were recorded from the relaxed first dorsal interosseous muscle. We also studied other motor cortical circuit functions; short-latency afferent inhibition (SAI), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Both the amount of IHI and SAI were significantly reduced in MCI patients as compared with control subjects, whereas SICI or ICF did not differ between them. The degree of IHI significantly correlated with neither the mini-mental state examination score nor the degree of SAI. Our results suggest that transcallosal connection between bilateral M1 is primarily involved in MCI, regardless of SAI dysfunction.

Keywords

Mild cognitive impairmentAlzheimer’s diseaseCorpus callosumInterhemispheric inhibitionShort-latency afferent inhibitionTranscranial magnetic stimulation

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Ryosuke Tsutsumi
    • 1
  • Ritsuko Hanajima
    • 1
  • Masashi Hamada
    • 1
  • Yuichiro Shirota
    • 1
  • Hideyuki Matsumoto
    • 1
  • Yasuo Terao
    • 1
  • Shinya Ohminami
    • 1
  • Yoshihiro Yamakawa
    • 2
  • Hiroyuki Shimada
    • 2
  • Shoji Tsuji
    • 1
  • Yoshikazu Ugawa
    • 3
    • 4
  1. 1.Division of Neuroscience, Department of NeurologyGraduate School of Medicine, University of TokyoTokyoJapan
  2. 2.Department of Geriatric MedicineGraduate School of Medicine, Osaka City UniversityOsakaJapan
  3. 3.Department of NeurologySchool of Medicine, Fukushima Medical UniversityFukushimaJapan
  4. 4.JST, Research Seeds ProgramFukushimaJapan