Failure of single-unit neuronal activity to differentiate globus pallidus internus and externus in Parkinson disease.
OBJECTIVE
The authors examine the validity of single-unit neuronal recordings as a method of differentiating the globus pallidus internus (GPi) from the GP externus (GPe) in Parkinson Disease.


METHODS
One hundred twenty-eight recordings of apparent single-unit activity used to help guide final electrode placement in eight patients who underwent pallidotomy were analyzed using sophisticated spike sorting methods, and 185 neurons were characterized for mean firing frequency and percent of firing within bursts. In addition, the total spectral power was calculated on the full measured waveform for each of 128 samples without spike sorting. No correlation was identified between these measures of neuronal activity and depth within the GP.


CONCLUSIONS
These results call into question the validity of relying on single-unit activity and microelectrode recordings in the operating room to localize lesion or electrode placement within the GPi during stereotactic pallidal surgery.
Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA. sschiff@gmu.edu
Steven J
SJ
Schiff
Brian K
BK
Dunagan
Robert M
RM
Worth
D000200:Action Potentials; D000368:Aged; D001931:Brain Mapping / Q000379:methods; D004594:Electrophysiology / Q000379:methods / Q000592:standards; D005917:Globus Pallidus / Q000166:cytology* / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008839:Microelectrodes; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D010300:Parkinson Disease / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*