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Impaired Spike Timing Dependent Cortico-Cortical Plasticity in Alzheimer's Disease Patients.
- Source :
-
Journal of Alzheimer's disease : JAD [J Alzheimers Dis] 2018; Vol. 66 (3), pp. 983-991. - Publication Year :
- 2018
-
Abstract
- Background: Mechanisms of cortical plasticity have been recently investigated in Alzheimer's disease (AD) patients with transcranial magnetic stimulation protocols showing a clear impairment of long-term potentiation (LTP) cortical-like plasticity mechanisms.<br />Objective: We aimed to investigate mechanisms of cortico-cortical spike-timing dependent plasticity (STDP) in AD patients investigating the connections between posterior parietal cortex (PPC) and primary motor cortex (M1).<br />Methods: We used a cortico-cortical paired associative stimulation (cc-PAS) protocol to repeatedly activate the connection between PPC and M1 of the left-dominant hemisphere in a sample of fifteen AD patients and ten age-matched healthy subjects. PPC transcranial magnetic stimulation preceded (ccPAS +5) or followed M1 stimulation (ccPAS - 5) by 5 ms. Motor-evoked potentials (MEPs) were collected to assess the time course of the after effects of cc-PAS protocol measuring MEP amplitude as index of cortico-cortical associative plasticity.<br />Results: In healthy subjects, ccPAS - 5 protocol induced the expected long-lasting increase of MEP amplitude compatible with LTP-like cortical plasticity while PAS +5 protocol induced the opposite effect. AD patients did not show any significant modification of the amplitude of MEP after both ccPAS protocols.<br />Conclusions: Our study shows that in AD patients the time-locked activation of human cortico-cortical connections is not able to form STDP, reflecting an impairment of a multi-factor plasticity process.
Details
- Language :
- English
- ISSN :
- 1875-8908
- Volume :
- 66
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of Alzheimer's disease : JAD
- Publication Type :
- Academic Journal
- Accession number :
- 30372679
- Full Text :
- https://doi.org/10.3233/JAD-180503