EFFECTS OF DIETARY BORON AND MAGNESIUM ON BRAIN-FUNCTION OF MATURE MALE AND FEMALE LONG-EVANS RATS

The electrocorticogram (ECoG) was recorded from 74 mature (175-day-old ) male and female Long-Evans rats following 75 days consumption of one of four diets resulting from the factorial combination of approximate ly 0 and 3 mug boron (B)/g diet crossed with 100 and 300 mug magnesium (Mg)/g diet. Effectiveness of the dietary manipulation was verified b y the determination of femur mineral concentrations. Spectral analysis (with 1 Hz resolution) of the ECoG showed decreased amplitude in the higher (7-12 Hz) frequencies and increased proportion of total amplitu de in the lower (4 and 5 Hz) frequencies in both the left and right he mispheres of rats fed the low B diets. Mg was not significantly relate d to brain electrical activity, and there were no significant interact ions between B and Mg with respect to the ECoG measures. Results indic ate that dietary B systematically influences brain electrical activity in mature rats and suggest that the principal effect of manipulating B intake is on the relative distribution of activity among frequencies . Thus, B may play an important role in the maintenance of brain activ ation. (C) 1993 Wiley-Liss, Inc.