Studies, such as MRI and PET, have shwn significant differences between the brain f a mre aggressive persn and anther ne wh has a diminished level f aggressin. Tgether with the prefrntal crtex, the hypthalamus and the amigdala seem t represent extremely imprtant places where t find the anatmic differences which affect the level f aggressiveness. Electric PerformX Testo stimulatin and lesins f these nuclei can increase r reduce the tendency f an individual t be vilent r nt. S, different traumas, lesins, r similar affectins can lead t imprtant changes in the behavir f a persn, which can include a serius frm f aggressiveness. Nevertheless, the ccurrence f these changes als depends n situatinal factrs. Fr example, research made thrughut electrical stimulatin n this crtical zne n animals, shw that the same kind f stimulatin which triggers aggressin against a weak ppnent might nt lead t the same result when it is invlved a strnger ne. Persns presenting a lw level f sertnin, which is a neurtransmitter invlved in the restraining f impulsive reactins, seem t develp a higher risk fr develping aggressive behavir.