A system for measuring electrophysiological multiple unit activity and extracellular dopamine concentration at single...

A technique is described for measuring electrophysiological multiple-unit activity and extracellular dopamine concentration with in vivo voltammetry at an array of 8 electrodes. In addition, new procedures in the construction of the voltammetric electrode that reduce the effects of capacitance and improve sensitivity are outlined. A system of relays controlling the connections of the electrode and associated systems is also detailed. Both in vitro and in vivo voltammetric selectivity tests indicate an almost exclusive response to dopamine. A large increase in extracellular dopamine concentration was detected in response to 2.5 mg/kg D-amphetamine. Both prestimulus and cortical stimulation evoked increases in striatal multiple-unit activity were measured.