8,655 Studies Reviewed. 86.9% Found Biological Effects. The Evidence is Clear.
Shield Your Body
Whole Body / GeneralPart of the Glaser Archive

METHOD FOR THE MEASUREMENT OF IMPEDANCE CHANGES IN BRAIN TISSUE

Bioeffects Seen

R. T. KADO, W. R. ADEY, M.D. · 1965

Share:

This 1965 research established methods for measuring brain tissue's electrical properties, providing foundation for understanding EMF-brain interactions.

Plain English Summary

Summary written for general audiences

This 1965 research developed methods for measuring electrical impedance changes in brain tissue, focusing on how electrical properties of neural tissue change during brain activity. The study established foundational techniques for detecting electrical changes in living brain tissue using bridge measurement methods. This early work laid groundwork for understanding how external electromagnetic fields might interact with the brain's electrical systems.

Why This Matters

This foundational research from 1965 represents crucial early work in understanding the electrical properties of brain tissue. While it predates modern EMF health concerns, the measurement techniques developed here became essential for studying how electromagnetic fields interact with neural tissue. The science demonstrates that brain tissue has measurable electrical impedance that changes during neuronal activity, which helps explain why the brain may be particularly sensitive to external electromagnetic influences. What this means for you is that your brain's electrical systems, which this research helped characterize, can potentially be influenced by the EMF emissions from devices like cell phones, WiFi routers, and smart meters. The reality is that understanding these baseline electrical properties of brain tissue was necessary before scientists could study how external EMF exposures might disrupt normal neural function.

Figures from the Original Paper

Diagrams extracted from the original research document.

diagramPage 1 - AI-described figure: Figure 1 illustrates a Wheatstone bridge setup for measuring impedance changes in brain tissue.
p. 1 of the original PDF
graphPage 2 - AI-described figure: Figure 3 illustrates the relationship between resistance and capacitance in a system with decade switching artifacts.
p. 2 of the original PDF

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 1 kHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 1 kHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

To report on the method used in making measurements of changes in electrical impedance of specific structures within the brain.

The method uses a Wheatstone bridge, high gain tuned amplifier, sampling switches, and a stabilized ...

The apparatus will produce a +15 mV DC output for 0.2% changes in the bridge impedance. Calibration ...

Cite This Study
R. T. KADO, W. R. ADEY, M.D. (1965). METHOD FOR THE MEASUREMENT OF IMPEDANCE CHANGES IN BRAIN TISSUE.
Show BibTeX
@article{method_for_the_measurement_of_impedance_changes_in_brain_tissue_g7141,
  author = {R. T. KADO and W. R. ADEY and M.D.},
  title = {METHOD FOR THE MEASUREMENT OF IMPEDANCE CHANGES IN BRAIN TISSUE},
  year = {1965},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

The study used electrical bridge measurement techniques to detect impedance changes in brain tissue. Bridge methods compare unknown electrical resistance to known reference values, allowing precise measurement of how brain tissue's electrical properties change during neural activity.
Brain tissue impedance changes because neural activity involves ion movement across cell membranes, altering the tissue's electrical resistance. When neurons fire, sodium and potassium ions flow in and out of cells, changing the electrical properties researchers can measure.
This research established that brain tissue has measurable electrical properties that change with activity. Understanding these baseline electrical characteristics became essential for later studies examining how external electromagnetic fields might influence or disrupt normal brain function.
The study used animal models to measure brain tissue impedance changes, though specific species aren't detailed in available information. Animal studies were standard practice in 1965 neurophysiology research for developing measurement techniques later applied to human studies.
Yes, changes in brain tissue impedance can indicate altered neural function or tissue damage. This measurement approach became valuable for detecting abnormal electrical activity patterns that might result from injury, disease, or potentially from electromagnetic field exposures.