I Zakharova1, J C Kohlmeyer1, M E Kornhuber2. 1. Dept. of Neurology, Universitätsklinikum Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany. 2. Dept. of Neurology, Universitätsklinikum Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany. Electronic address: malte.kornhuber@medizin.uni-halle.de.
Abstract
OBJECTIVE: Somatosensory evoked potentials (SSEPs) could be suitable for elucidating the properties of synaptic potentials (SPs). Two experiments were designed for this purpose. METHODS: 1st experiment: the sural nerve was stimulated in 13 subjects with single or trains of 3 stimuli (1Hz or 0.4Hz), the within train interstimulus interval (ISI) was stepwise extended from 2 to 10ms. Cz' against Fz, time interval 500ms. 2nd experiment: Gating was investigated in a paired stimulus paradigm with intervals of 0.7, 1, 2, 5s in 15 subjects after single and train stimuli (ISI 3ms) with equal stimulus and recording positions. RESULTS: 1st experiment: N1-P1, P1-N2a, and P2-N2b but not N37-P40 displayed a significant gain in amplitude following train stimuli compared with single stimuli. Significantly larger N1-P1 amplitude values were observed with 0.4Hz stimulus repetition compared with 1.0Hz. Short ISIs of 2-4ms led to higher N1-P1 amplitudes than obtained with longer ISIs of 7-10ms. 2nd experiment: recovery of the habituated N1-P1 amplitude was complete when the 2nd of 2 stimuli followed after 2s. CONCLUSIONS: SSEP vertex potential amplitudes (especially N1-P1) recorded after train stimuli presumably reflect the decay dynamics of excitatory postsynaptic potentials. Recovery of the habituated N1 (2nd experiment) was complete within 2s. SIGNIFICANCE: Our study may be relevant to study properties of excitatory synaptic potentials in diseases of the central nervous system such as e.g. epilepsy or migraine.
OBJECTIVE: Somatosensory evoked potentials (SSEPs) could be suitable for elucidating the properties of synaptic potentials (SPs). Two experiments were designed for this purpose. METHODS: 1st experiment: the sural nerve was stimulated in 13 subjects with single or trains of 3 stimuli (1Hz or 0.4Hz), the within train interstimulus interval (ISI) was stepwise extended from 2 to 10ms. Cz' against Fz, time interval 500ms. 2nd experiment: Gating was investigated in a paired stimulus paradigm with intervals of 0.7, 1, 2, 5s in 15 subjects after single and train stimuli (ISI 3ms) with equal stimulus and recording positions. RESULTS: 1st experiment: N1-P1, P1-N2a, and P2-N2b but not N37-P40 displayed a significant gain in amplitude following train stimuli compared with single stimuli. Significantly larger N1-P1 amplitude values were observed with 0.4Hz stimulus repetition compared with 1.0Hz. Short ISIs of 2-4ms led to higher N1-P1 amplitudes than obtained with longer ISIs of 7-10ms. 2nd experiment: recovery of the habituated N1-P1 amplitude was complete when the 2nd of 2 stimuli followed after 2s. CONCLUSIONS: SSEP vertex potential amplitudes (especially N1-P1) recorded after train stimuli presumably reflect the decay dynamics of excitatory postsynaptic potentials. Recovery of the habituated N1 (2nd experiment) was complete within 2s. SIGNIFICANCE: Our study may be relevant to study properties of excitatory synaptic potentials in diseases of the central nervous system such as e.g. epilepsy or migraine.
Authors: Alex I Wiesman; Elizabeth Heinrichs-Graham; Nathan M Coolidge; James E Gehringer; Max J Kurz; Tony W Wilson Journal: J Physiol Date: 2016-12-12 Impact factor: 5.182