title: Dopamine measurement during prolonged deep brain stimulation: a proof-of-principle study of paired pulse voltammetry.
abstract: OBJECTIVE
  Deep Brain Stimulation (DBS) has been effective in treating various neurological and psychiatric disorders; however, its underlying mechanism hasn't been completely understood. Fast scan cyclic voltammetry (FSCV) is a valuable tool to elucidate underlying neurotransmitter mechanisms of DBS, due to its sub-second temporal resolution and direct identification of analytes. However, since DBS-like high frequency stimulation evokes neurotransmitter release as well as extracellular pH shift, it is hard to isolate the neurotransmitter signal from the complex environment. Here we demonstrate the efficacy of a modified FSCV technique, Paired Pulse Voltammetry (PPV), in detecting dopamine (DA) release in the caudate nucleus during long-term electrical stimulation of the medial forebrain bundle (MFB) in the rat.
  
  
  METHODS
  Unlike traditional FSCV applying a single triangular waveform, PPV employs a binary waveform with a specific time gap (2.2 ms) in between the comprising pulses. DA measurement was performed with a carbon fiber microelectrode placed in the caudate nucleus and a twisted bipolar stimulating electrode in the MFB. PPV data was collected with the Wireless Instantaneous Neurochemical Concentration Sensing System (WINCS).
  
  
  RESULTS
  Using PPV, the detection of DA was evident throughout the long-term stimulation (5 minutes); however, without PPV,in vivoenvironmental changes including pH shift eventually obscured the characteristic oxidation current of DA at 0.6V.
  
  
  CONCLUSIONS
  These results indicate that PPV can be a valuable tool to accurately determine DA dynamics in a complexin vivoenvironment during long-term electrical stimulation.
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: Seungleal Brian
authors.initials: SB
authors.lastname: Paek
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: Emily Jane
authors.initials: EJ
authors.lastname: Knight
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America 55905 ; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: Su-Youne
authors.initials: SY
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: J Luis
authors.initials: JL
authors.lastname: Lujan
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, South Korea.
authors.forename: Dong Pyo
authors.initials: DP
authors.lastname: Jang
authors.affiliation: Division of Engineering, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Bennet
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America 55905 ; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America 55905.
authors.forename: Kendall H
authors.initials: KH
authors.lastname: Lee
keywords: Deep Brain Stimulation (DBS); Dopamine (DA); Fast Scan Cyclic Voltammetry (FSCV); Medial Forebrain Bundle (MFB); Paired Pulse Voltammetry (PPV)