Study on effect and mechanism of magnetic fields simulating EEG rhythm upon memory

Magnetic fields simulating EEG rhythm were used to stimulate Wistar rats to explore the effect of magnetic field on retrieval (recall) ability and its mechanism. The results indicated that most of the weak magnetic fields (>10 minutes) simulating the EEG rhythm of human brain impaired the retrieval of long-term memory significantly (P<0.05), but weak magnetic field with special rhythm may even have the capability of facilitating memory performance. And the effects of TMS on memory can last for at least several hours (5h) after TMS. Compared with control group, the release of NE, DA and 5-HT in hippocampus of stimulated group increased (P<0.05); While the release of ACh decreased (P<0.05). Through electronic microscope, morphological changes of nerve synapses in hippocampus of rats were observed after weak magnetic stimulation. The percentage of alpha and beta rhythm in EEG power spectra changed in cats after induced by weak magnetic fields simulating the EEG rhythm.