The Dynamics Of EEG Activity Associated To Morphine Dependence Development In The Prefrontal Cortex In Rhesus Monkey

The dynam i cs of EEG act i v i ty assoc i ated to morph i ne dependence development in the pref rental cortex in rhesus monkeyAbstractObjective: In order to understand their eventual role in the morphine dependence mechanism, the present study analyzed the relationship of EEG oscillation activities with morphine dependence development between in the ventral prefrontal cortex and in the dorsal prefrontal cortex in rhesus monkey. Methods: Electrodes were located in the ventral prefrontal cortex and in the dorsal prefrontal cortex of rhesus monkey. Raw electroencephalogram (EEG) signals were recorded with the digital data acquisition system. All electrophysiology data were stored on hard disk for subsequent off-line analysis.Result: Morphine effect period: there was a decline steadily in beta oscillation power from the first day in dorsal prefrontal cortex (vpfc). The decrease became to the marked level of variety from the 4 day to the 5 day. From then on beta oscillation power continues to climb both in vpfc and in dorsal prefrontal cortex (dpfc). But only the beta oscillation power in dpfc reached the marked level at the 7 day. Delta oscillation power was on the rise from the first day, adding up to marked level at the 4 day and the 5 day. Delta oscillation power in dpfc declined steadily until reaching the marked level at the 9 day. Theta oscillation power was on the rise from the beginning and made up the marked level, then dropping to the marked level at the 8 day in vpfc and at the 7 day in dpfc. Gamma oscillation power declined from the 2 day, reaching the marked level at the 3 day and the 5 day in vpfc and then continues to rise to the marked level at the 10 day in vpfc or at the 8 day in dpfc. After effect period: gamma oscillation power declined steadily, reaching the marked level at the 4, 6-10 day in vpfc. Other oscillation power had no marked variety.Conclusion: (1) Different areas of the prefrontal cortex play a different role in the processing of morphine dependence. (2) Every bands of oscillation in vpfc and in dpfc are possibly influenced by morphine addiction and all of these varieties reflect the dynamics of morphine addiction. (3) There is a very important period of morphine dependence from the 4 day to the 6 day after administering morphine. The turning points of the values of several oscillation powers located in the period. (4)Gamma bands oscillation power (related with recognition) had a steady marked decline in the procession of morphine dependence, which indicated a permanent impairment in cognitive ability. (5) To evaluate the function of the brain or conduct abstinence, there is a perspective to apply the variety of oscillation powers to estimate the impairment of the brain function.