Rapporteur report: weak field interactions in the central nervous system.
Experimental evidence was presented of the interaction of extremely low frequency (ELF) physiologically weak electric fields (that is, internal fields of around 1-1000 mV m(-1)) with tissues of the central nervous system and the consequences of this for visual and cognitive function. These internal fields are higher than those induced in the body by exposure to environmental EMFs, but are small compared to nerve excitation thresholds. Two papers considered the effect of weak electric fields directly applied to hippocampal tissue in vitro on neuronal excitability assessed from evoked responses and on the modulation of neural network activity involving large numbers of individual neurons. A review was presented of the effects on electrical measures of perceptual and cognitive processes and on the performance of various behavioural tasks in volunteers exposed to electromagnetic fields. Finally, two papers addressed the visual perception of flickering light--phosphenes--in volunteers exposed to ELF magnetic fields. The first examined possible physiological origins of this phenomenon and the second assessed the induced electric fields and currents in the retina, using complex dosimetric modelling. These papers were discussed in several plenary sessions and in one breakout group, all of which are briefly summarised in this report.
Saunders
R D
RD
National Radiological Protection Board, Chilton, Didcot, Oxfordshire, UK. richard.saunders@nrpb.org
D000818:Animals; D002490:Central Nervous System / Q000502:physiology / Q000528:radiation effects; D004560:Electricity; D004574:Electromagnetic Fields; D006801:Humans; D009415:Nerve Net / Q000502:physiology* / Q000528:radiation effects*; D009474:Neurons / Q000502:physiology* / Q000528:radiation effects*; D010719:Phosphenes / Q000502:physiology; D012160:Retina / Q000502:physiology* / Q000528:radiation effects*