Mobile phone emissions excite the part of the brain cortex nearest to the phone, but it is not clear if these effects are harmful, Italian researchers, quoted in a Reuters report said.
The Reuters report said the study, published in the Annals of Neurology, added to a growing body of research about mobile phones, their possible effects on the brain, and whether or not there was any link to cancer.
An estimated 730 million mobile phones are expected to be sold this year, according to industry forecasts, and nearly 2 billion people around the world already use them.
Of these, more than 500 million use a type that emits electromagnetic fields such as GSM radio phones.
The Reuters report said researchers used transcranial magnetic stimulation or TMS to check brain function while people used these phones.
They had 15 young male volunteers use a GSM 900 cellphone for 45 minutes. In 12 of the 15, the cells in the motor cortex adjacent to the cellphone showed excitability during phone use but returned to normal within an hour, the report said.
The researchers stressed that they had not shown that using a mobile phone was bad for the brain in any way, but people with conditions such as epilepsy, linked with brain cell excitability, could potentially be affected.