Electrical
signals between neurons generate electric fields that radiate out of brain
tissue as electrical waves that can be picked up by electrodes touching a
person's scalp. Measurements of such brainwaves in EEGs provide powerful
insight into brain function and a valuable diagnostic tool for doctors. Indeed,
so fundamental are brainwaves to the internal workings of the mind, they have
become the ultimate, legal definition drawing the line between life and death. Brainwaves
change with a healthy person's conscious and unconscious mental activity and
state of arousal. But scientists can do more with brainwaves than just listen
in on the brain at work-they can selectively control brain function by
transcranial magnetic stimulation (TMS). This technique uses powerful pulses of
electromagnetic radiation beamed into a person's brain to jam or excite
particular brain circuits. Although a cell phone is much less powerful than
TMS, the question still remains: Could the electrical signals coming from a
phone affect certain brainwaves operating in resonance with cell phone
transmission frequencies? After all, the caller's cerebral cortex is just
centimeters away from radiation broadcast from the phone's antenna. Two studies
provide some revealing news. The first, led by researchers of the Brain Science
Institute, Swinburne University of Technology in Melbourne, Australia, tested
whether cell phone transmissions could alter a person's brainwaves. The
researchers monitored the brainwaves of 120 healthy men and women while a Nokia
6110 cell phone—one of the most popular cell phones in the world—was strapped
to their head.
A computer
controlled the phone's transmissions in a double-blind experimental design,
which meant that neither the test subject nor researchers knew whether the cell
phone was transmitting or idle while EEG data were collected. The data showed
that when the cell phone was transmitting, the power of a characteristic
brain-wave pattern called alpha waves in the person's brain was boosted
significantly. The increased alpha wave activity was greatest in brain tissue
directly beneath to the cell phone, strengthening the case that the phone was
responsible for the observed effect. Alpha waves fluctuate at a rate of eight
to 12 cycles per second (Hertz). These brainwaves reflect a person's state of
arousal and attention. Alpha waves are generally regarded as an indicator of
reduced mental effort, "cortical idling" or mind wandering. But this
conventional view is perhaps an oversimplification. Researchers argue that the
alpha wave is really regulating the shift of attention between external and
internal inputs. Alpha waves increase in power when a person shifts his or her
consciousness of the external world to internal thoughts; they also are the key
brainwave signatures of sleep. If cell phone signals boost a person's alpha
waves, does this nudge them subliminally into an altered state of consciousness
or have any effect at all on the workings of their mind that can be observed in
a person's behavior? In the second study, researchers at the Loughborough
University Sleep Research Centre in England devised an experiment to test this
question. The result was surprising. Not only could the cell phone signals
alter a person's behavior during the call, the effects of the disrupted
brain-wave patterns continued long after the phone was switched off.
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