1. Lecture 38 April 24,2017
Behavioral and Cognitive Effects of Electromagnetic
Field Exposures
Sheila A. Johnston and John A. D’Andrea

2. Introduction 1. Brain 100 billion nerve cells
2. Water has absorption band at 2.45 GHz that leads to heating
3. Heating is the established mechanism for interaction at the time this chapter was written .
4. Characterization by SAR at RF and Microwave
5. At ELF by volts per meter: V/m) and ampere per square meter: A/m2)

3. Some History
1 A lot of work went into the study of the Russian reports of changes in Brain Function and the blood brain barrier.
2. Results were not repeated and all kinds of questions about why.
3. The results not included in Western Safety Standards

4. Microwave Effects 1. Microwave Hearing 2. Thermal Sensors on skin.
3.For example a small area (37 cm2) of forehead was exposed for 4 s, the mean absolute threshold of warmth varied across frequency. At 3 GHz this threshold was 33.5 mW/cm2, at 10 GHz it was 12.6 mW/cm2, and at frequencies for far infrared (IR) it was 4.2 mW/cm2.
4. Why the difference?

5. Thermal Sensing
Justesen et al. (1982) studied the detection on the forearm of IR and 2450 MHz on a 15-cm diameter aperture in a wall of microwave-absorbent material to limit the exposed area of skin. Using a double-staircase psychophysical method, the subjects were given 10-s exposures. Thresholds of 26.7 and 1.7 mW/cm2 were documented for 2450 MHz and IR exposures, respectively.

6. Thermal Sensing by Blick 1997
They used long duration (10 s), large area (327 cm2) stimuli to minimize temporal or spatial summation. Frequencies of 2.45, 7.5, 10, 35, and 94 GHz as well as IR were tested. From 2.45 to 94 GHz, the detection thresholds decreased more than an order of magnitude. The 2450 MHz threshold (63.1 mW/cm2) and the IR detection threshold (5.34 mW/cm2) were roughly 2.5 times the thresholds found by Justesen et al. (1982).

7. Microwave Performance Disruption
1. Thresholds to disrupt simple operant behaviors during acute whole body exposure were determined to be near 4 W/kg The estimated threshold whole body SAR range was 3.2–3.6 W/kg.
2. Disruption of ongoing behavior during acute MW exposure is generally associated with 1o C or greater increase of body temperature.

8. Memory
Mickley et al. (1994) and Mickley and Cobb (1998) investigated memory deficits in rats exposed to MWs and determined that the threshold for memory effects was 10 W/kg. Similarly, Luttges (1980) evaluated the effects of MW exposure on learning and memory in mice and found an enhancement of performance (estimated whole body SAR 13 W/kg).

9. Memory
It is well established that spatial memory requires glutamate neurotransmission in Schaffer collateral fibers released to glutamate* receptors of CA1
pyramidal cells of the hippocampus. Long-term potentiation in the CA1 cells results in synapse alteration and spatial memory and learning. Even though brain along with body temperatures fluctuates 2–3 oC in normal physiological conditions, spatial memory is quite robust and occurs at brain temperatures between 30 and 39 oC in rats (Andersen
and Moser, 1995).

10. Memory
1. Many conflicting results with most failing to show any changes in rats or mice at low levels.
The animals exposed to MW with the brain average SAR of 25W/kg for 4 d showed statistically significant decreases in the transition
in number of correct choices in the reversal task, compared to sham-exposed or cage control animals. However, rats exposed at the brain average SAR of 7.5W/kg for either 4 d or for 4 weeks showed no T-maze performance impairments

11. Conclusions: Animals: Spatial Memory Replications and Confirmations
In conclusion, MW exposure appears to disrupt spatial memory in rats at a dose at or
above the whole body threshold of 4 W/kg in a fashion similar to simple tasks of perception. This is in line with the mechanism of whole body temperature increases of 1oC or higher.

12. Microwave Cognitive Effects : Human Studies (Table 4.2)
1.During the period 1999–2005, a variety of studies have been done, both to measure the dose rate to the head and to evaluate the effects of mobile phone irradiation on cognitive processes in humans .
2. No established evidence of memory deficits
3. Some results have been reported of memory
and attention facilitation.
4. Many show no cognitive effects n

13. Microwave Effects on the Electroencephalogram
1. EEG results to variable to say much as of
2. More recent work seem to indicate changes.

14. Blood–Brain Barrier Studies
1. Lots of work and very controversial.
2. My impressing is no observed effects with temperature changes below 1o C.

15. Electrosensitivity in Humans
1. No real reports in the text.
2. In the double blind studies I have read the people could not tell when the radio signal was on.
3. The people who have these problems have real problems.
4. The effects can not be thermal. They appear to occur after relatively long term exposures. No good explanation of the cause and effects.

16. Detection of Extremely Low-Frequency Electric and Magnetic Fields
1. Ampullae of Lorenzini, for detection of ELF fields at extraordinarily low intensities around 5 nV/cm
2. Magnet fields detection at 0.5x 10-7 T
3. No cognitive effects measured at 50 mT, Hz, 26 mT static fields in rates. ICR frequency for Ca.
4. Detection threshold for primates 3–15 kV/m

17. Electric Field Stimulation
1. Visual system phosphenes can be generated at the retina by magnetic fields of near 15 mT oscillating at 50–60 Hz, producing electric fields in tissue on the order of 1 V/m (Reilly, 1998
2. Threshold for cognitive stimulation near20V/m.
3. Deep brain stimulation near 100–500 mV/m
4. Externally applied 1.6–80 kV/m,

18. Human Perception of E fields
1. Varied from less than 2kV/m
2. Average for women 17.5 kV/m
3. Average for men 6.7 kV/m.

19. Extremely Low-Frequency Cognitive Effects: Animals
Adverse reactions to CNS electrostimulation below excitation thresholds ( B = 0.75 mT at
50 Hz)
Effects on spatial memory of rats, mice, and voles at power frequencies at 100 mT and above
Also effects of 0.75 mT at 50 Hz field exposure on acquisition and retention of spatial memory in two species (rats and mice)

20. Shielding Static Magnetic Field
Choleris et al. (2001) did a series of experiments which repeatedly showed that a 2 h stay in a Mu-metal box, shielding the animal from ambient magnetic and electric environment, resulted in a
significant decrease in response latencies, which indicated a significant increase in nociceptive
sensitivity and reduction in stress-induced analgesia (SIA) in C57 mice.

21. Extremely Low-Frequency Cognitive Studies: Humans
A recent review by Cook et al. (2002) evaluated cognitive effects and found incomplete and negative findings that ELF MF can alter human cognition or electrophysiology at <500 mT.
Crasson et al. (1999) They demonstrated event-related brain potential (ERP) latency and reaction time slowing in the oddball paradigm, a visual discrimination task, after real magnetic field exposure.

22. Humans
They investigated cognitive effects of a continuous, vertical ELF magnetic field of 20 and 400 mT 50 Hz in healthy young men during performance on cognitive tests Thirty-two volunteers (mean y) participated in this double blind study.
The total duration of the exposure was 65 min. No effect of MF exposure was observed on
performance.