A new MRI approach for accurately implanting microelectrodes into deep brain structures of the rhesus monkey (Macaca mulatta)

The accurate implantation of microelectrodes is a significant difficulty facing many neurophysiologists. This paper reports on a new method used to promote the precise positioning of electrode implantation through magnetic resonance imaging (MRI), allowing both the relevant brain structure and the MRI-visible external markers anchored on the skull (in this case rigid glass tubes with a 0.5 mm internal diameter) to be displayed. By referencing these markers, the coordinates of the brain target were calculated. Using this novel approach, recording electrodes were successfully implanted into the superior colliculus (SC) of rhesus monkeys, with an error <1 mm, and its neuronal discharge signals were obtained. This new method allows neurophysiologists to precisely target the small deep brain structures of monkeys and study their electrophysiological characteristics in detail.

Research highlights▶ The accuracy of electrode implantation through MRI has been promoted. ▶ Slender rigid glass tubes were used as external markers. ▶ Tetrodes have been implanted in monkey's SC with the error <1 mm. ▶ The new method is convenient, economical and universally available.