A novel electrophysiological-behavioral recording system, developed by Experimetria Ltd., Hungary in cooperation with our Department, was used to study the effects of manganese, a neurotoxicant frequently causing human nervous system disease in occupational exposure. Male Wistar rats were equipped with a “crown” enabling the recording of electrocorticogram (ECoG) in awake, freely moving state. One 60-min recording session per week was held for 10 weeks, in which the rats’ movements in an open field (OF) box and their ECoG were simultaneously recorded. After the 2nd week, treated rats had 7.5 mg/1 MnCf in the drinking water (control: normal tapwater) and further 8 recordings were made. From the OF records, ambulation distance and the time spent with ambulation, local activity and immobility was obtained. From the ECoG, power spectrum and total power was calculated. In the first weeks of Mn exposure, the rats’ motility substantially decreased, and these changes showed little further progression. The decay of motility during one 60-min session was also stronger in exposed rats. The total power of ECoG increased in the first 4 weeks but the spectrum was hardly changed. The total power and spectrum of ECoG and the level of motility were apparently correlated, and the functional alterations showed some dependence on treatment time and/or summed dose. Combined, repeated ECoG and motility recording is suitable to follow-up the development of neurotoxicity induced by Mn, and possibly other environmental neurotoxicants
