Event-related potential which represents a large positive wave which varies in amplitude and depends on subject's capability as well as on stimulus modality on which subject needs to react and appears around 300 ms after stimulation is called event related potential P300. In 1965. Sutton and the assistants were the first to suggest division of evocated potentials, according to the stimulus that provoke them, on "exogenous" (under the influence of exogenous stimulus) and "endogenous" or "cognitive" provoked by endogenous stimulus, which depends on the state of consciousness (vigilance), attention, concentration and especially, the type of the task a subject needs to perform during the recording. One of the most studied responses of the event-related potentials is so called "P300", the late positive wave complex which appears around 300 500ms after the stimulus. It is gained when the subjects' attention is focused on the signal which rarely appears, especially if the signal has some emotional or motivational meaning. The aim of this work was to determine whether there was a difference in latency and amplitude of the event related potential P300 when the button is pushed with dominant hand compared with nondominant hand in both males and females. The experiment included 30 subjects (15 males and 15 females). P300 potential was provoked with the auditive "oddball" paradigm. Event-related potencial P300 is recorded with 10-20 system. Cz electrode is set in the middle of nazion-inion line, while Fz electrode is set on the third of nazion-inion line above frontal lobe. In classical "oddball" paradigm, when a subject reacted on the signal by pushing the button with dominant hand, the value of Fz end Cz latency was significantly shorter in comparison to the values of Fz end Cz latency gained by pushing the button with non-dominant hand (left hand) in males, while such differences were not found in females. 

Cardiovascular diseases are one of the most significant social-medical problems. Having on mind their importance, the risk factors have been defined. Numerous clinical and epidemiological studies showed that deficit of magnesium in the human organism has a certain contribution in etiology, pathogenesis and evolution of cardiovascular diseases. RASKO, Rakovica's study of cardiovascular diseases, found out that these diseases are more frequent at the locations where
soft water with decreased content of magnesium is being used as drinking water. Magnesium is an integral part of about 300 enzyme systems in which catalyst's role have adenositriphospathase as Mg-ATP, a part of NaKATP-ase, exogenous and endogenous pumps for calcium, etc. A normal plasmatic concentration of magnesium is 0,8-1 mmol/l. Plasmatic level of magnesium is not directly correlated with actually content in an organism since 33% of plasmatic magnesium is connected with plasma's proteins and that's why hypoproteinemia can cause a false hypomagnesemia. The normal values of magnesemia don't exclude deficit of magnesium in an organism since PTH and calcitonin mobilize magnesium from the bones. Hypomegnesemia is caused by improper and irrational nutrition, hormone disturbances, and different conditions and diseases of an organism. Magnesium has vasodiletatoric, antianginosic, hypolipemic, antiagregatic effects. Mechanism of magnesium's effect is based on its physiological role in an organism, i.e. on correction of hypomagnesemia. In preventive and therapeutic purposes magnesium's compounds are used peroraly and parenteraly. With parenteral use the plasmatic concentrations of more than physiological 2,5-7,5 mEq/l can be attained in which case somnolentia can be appeared but not a coma nor depression of breathing. In prevention and therapy of cardiovascular diseases magnesium has a significant place in the largest number of cases as an adjuvant drug