Brain Temperature Changes By Visual Stimuli In Drug Addicts: A Pilot Study

Objective: Bold-fMRI studies have shown that different brain regions ofdrug-dependent persons in addiction-related environmental cues are activated, whichcan produce craving and relapse.This study is to explore brain temperature changes indifferent brain addicted regions of short-term abstinent heroin and methamphetamineaddicts using magnetic resonance spectroscopy(MRS),and to investigate whetherbrain temperature changes can be used as quantitative indicators determining theextent of drug craving.Methods: Fourteen heroin addicts at short-term abstinent time and sixteen randomlyassigned healthy volunteers (age, years of education matched), twelvemethamphetamine addicts at short-term abstinent time and nine randomly assignedhealthy volunteers (age, years of education matched) underwent MRS scanning.Thevolumes of interest (ROI) were located in the prefrontal cortex (PFC) and bilateralhippocampus.First resting-state MRS scanning was performed on subjects,and thendid MRS scanning again under visual stimulation while subjects were asked tocarefully watch the heroin/methamphetamine-related cue images.Subjects’ braintemperatures before and after visual stimulation were obtained from the formulaT=37+100(CSNAA一CSNAAref) via measured NAA chemical shift.In addition,subjects’state of anxiety and depression were assessed.Results:1.Before and after visual stimulation,the PFC brain temperature of heroinand methamphetamine addicts did not show statistical significance.Compared with thenormal group,there were no statistically significant changes in PFC brain temperatureof heroin and methamphetamine addicts before and after visual stimulation.2. Beforeand after visual stimulation,bilateral hippocampal temperature changes ofmethamphetamine addicts had no significant differences and no statisticalsignificance.Compared with the normal group,no statistical significance was found inthe right hippocampus temperature changes of methamphetamine addicts before andafter visual stimulation.3. Compared with the normal group,no statistical significancewas found in the left hippocampus temperature changes of methamphetamine addicts before visual stimulation,however,there was statistical significance in the lefthippocampus temperature changes of methamphetamine addicts after visualstimulation (P<0.05).Conclusion:1.This preliminary study shows that heroin andmethamphetamine-related visual cues are not enough to cause significant changes inthe PFC brain temperature of subjects.2.When exposing to visual stimulation the lefthippocampus temperature of methamphetamine addicts is lower than the normalgroup,which indicates that drug memories are awakened by methamphetamine-relatedvisual cues,thereby affecting their brain temperature change by affecting the cerebralblood flow of the left hippocampus,while visual stimulation on the changes of righthippocampus brain temperature is weak.3.This exploratory study also shows thatMRS can be possibly used as a quantitative indicator to monitor temperature changesin different brain regions of drug addicts,and thus can determine the extent of drugcraving and dependence of drug addicts.