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. 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). 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. 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. 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.

Impaired spike timing dependent cortico-cortical plasticity in Alzheimer's disease patients / Di Lorenzo, F; Ponzo, V; Motta, C; Bonni, S; Picazio, S; Caltagirone, C; Bozzali, M; Martorana, A; Koch, G. - In: JOURNAL OF ALZHEIMER'S DISEASE. - ISSN 1387-2877. - 66:3(2018), pp. 983-991. [10.3233/JAD-180503]

Impaired spike timing dependent cortico-cortical plasticity in Alzheimer's disease patients

Picazio S;
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. 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). 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. 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. 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.
2018
Alzheimer’s disease; connectivity; long-term potentiation; motor cortex; parietal cortex; plasticity; spike-timing dependent plasticity
01 Pubblicazione su rivista::01a Articolo in rivista
Impaired spike timing dependent cortico-cortical plasticity in Alzheimer's disease patients / Di Lorenzo, F; Ponzo, V; Motta, C; Bonni, S; Picazio, S; Caltagirone, C; Bozzali, M; Martorana, A; Koch, G. - In: JOURNAL OF ALZHEIMER'S DISEASE. - ISSN 1387-2877. - 66:3(2018), pp. 983-991. [10.3233/JAD-180503]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1561381
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