What are the biophysics of the interaction between weak complex magnetic fields and neuronal processes?
Complex weak magnetic fields do not interact with neural processes in the way simple high-amplitude fields do. A technique known as Trans-cranial Magnetic Stimulation (TMS) uses simple magnetic pulses (in the Tesla region) to induce instant and specific effects in neural responses. It does this by employing a pulse, so intense, that it induces immediate responses in neurons (depolarisation resulting in action potentials) which then impacts on cognitive processing (see, Walsh, & Pascual-Leone, 2003). The biophysics of this process are reasonably well known. A magnetic field in the Tesla region is very unlikely to ever be present in the normal environment and so could not be responsible for haunt-type reports and hallucinations. However, this mechanism is totally unlike that which results from exposure to weak complex magnetic fields. This procedure is known as Trans-Cerebral Stimulation (TCS: see Persinger & Koren, 2001) and its effects build up over time (an observer needs to be expose
