Exploring the form- And time-dependent effect of low-frequency electromagnetic fields on maintenance of hippocampal long-term potentiation.

PAPER pubmed The European journal of neuroscience 2020 In vitro study Effect: harm Evidence: Low

Read original paper → DOI: 10.1111/ejn.14705 PMID: 32065697 Evidence Lab

Abstract

Low-frequency electromagnetic field (LF-EMF) stimulation is an emerging neuromodulation tool that is attracting more attention because of its non-invasive and well-controlled characteristics. However, the effect of different LF-EMF features including the forms and the time of addition on neuronal activity has not been completely understood. In this study, we used multi-electrode array (MEA) systems to develop a flexible in vitro magnetic stimulation device with plug-and-play features that allows for real-time delivery of LF-EMFs to biological tissues. Crucially, the method enables different forms of LF-EMF to be added at any time to a long-term potentiation (LTP) experiment without interrupting the process of LTP induction. We demonstrated that the slope of field excitatory postsynaptic potentials (fEPSPs) decreased significantly under post or priming uninterrupted sine LF-EMFs. The fEPSPs slope would continue to decline significantly when LF-EMFs were added two times with a 20-min interval. Paired-pulse ratio (PPR) was analyzed and the results reflected that LF-EMFs induced LTP was expressed postsynaptically. The results of pharmacological experiments indicated that AMPA receptor activity was involved in the process of LTP loss caused by post-LF-EMFs. Moreover, the effect of priming sine or Quadripulse stimulation (QPS)-patterned LF-EMFs depended on the time interval between the end of LF-EMF and the beginning of baseline recording. Interestingly, the effect of sine LF-EMFs on LTP would not disappear within 120 min, while the impact of QPS-patterned LF-EMFs on LTP might disappear after 90 min. These results indicated that LF-EMF might have a form- and time-dependent effect on LTP.

AI evidence extraction

At a glance

Study type

In vitro study

Effect direction

harm

Population

—

Sample size

—

Exposure

ELF magnetic stimulation device (in vitro)

Evidence strength

Low

Confidence: 74% · Peer-reviewed: yes

Main findings

Using an in vitro MEA-based system, uninterrupted sine LF-EMFs applied post-induction or as priming were associated with a significant decrease in fEPSP slope (reduced LTP maintenance), with further decline when LF-EMFs were applied twice separated by 20 minutes. PPR analysis suggested the LF-EMF–related LTP changes were expressed postsynaptically, and pharmacological results indicated AMPA receptor activity was involved in LTP loss after post-LF-EMFs. Effects depended on waveform and timing; sine effects persisted within 120 minutes, while QPS-patterned effects might disappear after 90 minutes.

Outcomes measured

Hippocampal long-term potentiation (LTP) maintenance
Field excitatory postsynaptic potential (fEPSP) slope
Paired-pulse ratio (PPR)
AMPA receptor involvement (pharmacological experiments)
Time course of LTP effects (up to 120 min for sine; ~90 min for QPS)

Limitations

In vitro study; findings may not generalize to in vivo or human exposure
Specific LF-EMF parameters (e.g., frequency, field strength) not provided in the abstract
Sample size and statistical details not reported in the abstract

View raw extracted JSON

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "magnetic stimulation device (in vitro)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Hippocampal long-term potentiation (LTP) maintenance",
        "Field excitatory postsynaptic potential (fEPSP) slope",
        "Paired-pulse ratio (PPR)",
        "AMPA receptor involvement (pharmacological experiments)",
        "Time course of LTP effects (up to 120 min for sine; ~90 min for QPS)"
    ],
    "main_findings": "Using an in vitro MEA-based system, uninterrupted sine LF-EMFs applied post-induction or as priming were associated with a significant decrease in fEPSP slope (reduced LTP maintenance), with further decline when LF-EMFs were applied twice separated by 20 minutes. PPR analysis suggested the LF-EMF–related LTP changes were expressed postsynaptically, and pharmacological results indicated AMPA receptor activity was involved in LTP loss after post-LF-EMFs. Effects depended on waveform and timing; sine effects persisted within 120 minutes, while QPS-patterned effects might disappear after 90 minutes.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro study; findings may not generalize to in vivo or human exposure",
        "Specific LF-EMF parameters (e.g., frequency, field strength) not provided in the abstract",
        "Sample size and statistical details not reported in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "low-frequency electromagnetic fields",
        "LF-EMF",
        "neuromodulation",
        "in vitro",
        "multi-electrode array",
        "hippocampus",
        "long-term potentiation",
        "fEPSP",
        "paired-pulse ratio",
        "AMPA receptor",
        "quadripulse stimulation",
        "waveform dependence",
        "timing dependence"
    ],
    "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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