▁that ▁are ▁bound ▁to ▁a ▁bi olog ically ▁relevant ▁marker ▁such ▁as ▁gl uc ose . ▁The ▁more ▁activation ▁in ▁the ▁brain ▁the ▁more ▁that ▁region ▁requires ▁nut ri ents , ▁so ▁higher ▁activation ▁appears ▁more ▁bright ly ▁on ▁an ▁image ▁of ▁the ▁brain . ▁P ET ▁sc ans ▁are ▁becoming ▁more ▁frequently ▁used ▁by ▁research ers ▁because ▁P ET ▁sc ans ▁are ▁activ ated ▁due ▁to ▁met abol ism ▁whereas ▁M RI ▁is ▁activ ated ▁on ▁a ▁more ▁phys i ological ▁basis ▁( s ug ar ▁activation ▁versus ▁o xygen ▁activation ). ▁ ▁Trans c ran ial ▁magnetic ▁stim ulation ▁Trans c ran ial ▁magnetic ▁stim ulation ▁( T MS ) ▁is ▁essentially ▁direct ▁magnetic ▁stim ulation ▁to ▁the ▁brain . ▁Because ▁electric ▁curr ents ▁and ▁magnetic ▁fields ▁are ▁intr ins ically ▁related , ▁by ▁stim ulating ▁the ▁brain ▁with ▁magnetic ▁p uls es ▁it ▁is ▁possible ▁to ▁inter f ere ▁with ▁specific ▁lo ci ▁in ▁the ▁brain ▁to ▁produce ▁a ▁predict able ▁effect . ▁This ▁field ▁of ▁study ▁is ▁currently ▁receiving ▁a ▁large ▁amount ▁of ▁attention ▁due ▁to ▁the ▁potential ▁benefits ▁that ▁could ▁come ▁out ▁of ▁better ▁understanding ▁this ▁technology . ▁Trans c ran ial ▁magnetic ▁movement ▁of ▁particles ▁in ▁the ▁brain ▁shows ▁promise ▁for ▁drug ▁target ing ▁and ▁delivery ▁as ▁studies ▁have ▁demonstrated ▁this ▁to ▁be ▁non in vas ive ▁on ▁brain ▁phys i ology . ▁ ▁Trans c ran ial ▁direct ▁current ▁stim ulation ▁Trans c ran ial ▁direct ▁current ▁stim ulation ▁( t D CS ) ▁is ▁a