title: Cortically evoked responses of human pallidal neurons recorded during stereotactic neurosurgery.
abstract: Responses of neurons in the globus pallidus (GP) to cortical stimulation were recorded for the first time in humans. We performed microelectrode recordings of GP neurons in 10 Parkinson's disease (PD) patients and 1 cervical dystonia (CD) patient during surgeries to implant bilateral deep brain stimulation electrodes in the GP. To identify the motor territories in the external (GPe) and internal (GPi) segments of the GP, unitary responses evoked by stimulation of the primary motor cortex were observed by constructing peristimulus time histograms. Neurons in the motor territories of the GPe and GPi responded to cortical stimulation. Response patterns observed in the PD patients were combinations of an early excitation, an inhibition, and a late excitation. In addition, in the CD patient, a long-lasting inhibition was prominent, suggesting increased activity along the cortico-striato-GPe/GPi pathways. The firing rates of GPe and GPi neurons in the CD patient were lower than those in the PD patients. Many GPe and GPi neurons of the PD and CD patients showed burst or oscillatory burst activity. Effective cathodal contacts tended to be located close to the responding neurons. Such unitary responses induced by cortical stimulation may be of use to target motor territories of the GP for stereotactic functional neurosurgery. Future findings utilizing this method may give us new insights into understanding the pathophysiology of movement disorders.
authors.affiliation: Department of Neurological Surgery, Wakayama Medical University, Wakayama, Japan. hirokin@wakayama-med.ac.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nishibayashi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Ogura
authors.forename: Koji
authors.initials: K
authors.lastname: Kakishita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Tachibana
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nambu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kita
authors.forename: Toru
authors.initials: T
authors.lastname: Itakura
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000368:Aged; D001703:Biophysics; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005917:Globus Pallidus / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D009493:Neurosurgery / Q000379:methods*; D010300:Parkinson Disease / Q000473:pathology* / Q000601:surgery; D011930:Reaction Time / Q000502:physiology; D013223:Statistics as Topic; D013238:Stereotaxic Techniques