Non-conductive and miniature fiber-optic imaging system for real-time detection of neuronal activity in time-varying electromagnetic fields.

Biosensors & bioelectronics · 2017 · Mixed · Low evidence

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MixedLow evidencePaper 4825

Study snapshot

PublicationBiosensors & bioelectronics · 2017

Study typeother

Reported directionMixed

Evidence ratingLow

Abstract

Establishing an appropriate threshold value for neuronal modulation by time-varying electromagnetic field (EMF) exposure is important for developing international guidelines to protect against the potential health effects, and to design a variety of medical devices. However, it is technically difficult to achieve real-time detection of neuronal activity under repetitive and long-term exposure to EMF. For this purpose, we developed a non-conductive, miniature, and flexible fiber-optic imaging system that does not affect the electromagnetic noise, induction heating, or vibration in a high-intensity and repetitive time-varying EMF exposure. Using the proposed system, we succeeded at real-time detection of spontaneous Ca oscillations in single neuronal and glial cells, as well as synchronized bursting activities of multiple neuronal networks at a micrometer-scale and millisecond-order spatiotemporal resolution during long-term EMF exposure (sinusoidal wave, 20kHz, 8.6mT, >30min). The results indicated that short-term (<5min) exposure-related neuronal modulation was not detectable; however, long-term (15-30min) exposure was observed to depress neuronal activities. In addition, the simultaneous and real-time recording of neuronal activity and the environmental temperature revealed that the neuronal modulation was accompanied by a 0.5-1°C rise in the temperature of the culture medium induced by the heat generation of exposure coils. These findings suggest that our real-time imaging system can be used for precise evaluation of the threshold values and clarification of the mechanisms of neuronal modulation induced by time-varying EMF exposure.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionmixed

PopulationCultured neuronal and glial cells; neuronal networks (in vitro)

Sample sizeNot supplied

ExposureELF · 0.02 MHz · >30min (with comparisons: <5min; 15–30min)

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

A non-conductive miniature fiber-optic imaging system enabled real-time recording of calcium oscillations and network bursting during sinusoidal 20 kHz, 8.6 mT EMF exposure (>30 min). Short-term exposure (<5 min) showed no detectable neuronal modulation, while longer exposure (15–30 min) was associated with depressed neuronal activity and a concurrent 0.5–1°C rise in culture-medium temperature attributed to heating from exposure coils.

Outcomes measured

Real-time detection of spontaneous Ca oscillations in single neuronal and glial cells
Synchronized bursting activities of multiple neuronal networks
Neuronal activity modulation (depression) during EMF exposure
Culture medium temperature change during exposure

Limitations

In vitro cell culture model; generalizability to humans not addressed in abstract
Sample size not reported in abstract
Observed modulation accompanied by temperature rise, suggesting potential thermal confounding from exposure coils

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": 0.02,
    "sar_wkg": null,
    "duration": ">30min (with comparisons: <5min; 15–30min)"
  },
  "population": "Cultured neuronal and glial cells; neuronal networks (in vitro)",
  "sample_size": null,
  "outcomes": [
    "Real-time detection of spontaneous Ca oscillations in single neuronal and glial cells",
    "Synchronized bursting activities of multiple neuronal networks",
    "Neuronal activity modulation (depression) during EMF exposure",
    "Culture medium temperature change during exposure"
  ],
  "main_findings": "A non-conductive miniature fiber-optic imaging system enabled real-time recording of calcium oscillations and network bursting during sinusoidal 20 kHz, 8.6 mT EMF exposure (>30 min). Short-term exposure (<5 min) showed no detectable neuronal modulation, while longer exposure (15–30 min) was associated with depressed neuronal activity and a concurrent 0.5–1°C rise in culture-medium temperature attributed to heating from exposure coils.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro cell culture model; generalizability to humans not addressed in abstract",
    "Sample size not reported in abstract",
    "Observed modulation accompanied by temperature rise, suggesting potential thermal confounding from exposure coils"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "fiber-optic imaging",
    "non-conductive",
    "real-time detection",
    "neuronal activity",
    "glial cells",
    "calcium oscillations",
    "network bursting",
    "time-varying electromagnetic fields",
    "20 kHz",
    "8.6 mT",
    "temperature rise",
    "induction heating"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.42,
      "reason": "Abstract discusses establishing threshold values for neuronal modulation to inform international guidelines for EMF exposure."
    }
  ]
}

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

Identifiers and source

DOI: 10.1016/j.bios.2016.09.024
PubMed: 27649336

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