title: Effective spread and timecourse of neural inactivation caused by lidocaine injection in monkey cerebral cortex.
abstract: We studied the effective spread of lidocaine to inactivate neural tissue in the frontal cortex of the rhesus monkey. Injections of 2% lidocaine at 4 microl/min were made while units were recorded 1 or 2 mm away. To inactivate units 1 mm away from the injection site 100% of the time, 7 microl of lidocaine had to be injected. To inactivate units 2 mm away from the injection site 100% of the time, 30 microl of lidocaine were required. Units were maximally inactivated around 8 min after the start of a lidocaine injection, and they gradually recovered, regaining most of their initial activity by around 30 min after the start of an injection. The volume of lidocaine required to inactivate neurons > 90% of the time could be estimated by the spherical volume equation, V = 4/3 pi (r)3. To prolong the inactivation, a slower infusion of lidocaine subsequent to an initial bolus was effective. Saline control injections had no effect. These results allow both a prediction of the timecourse of neural inactivation and an estimate of the spread of neural inactivation following injection of lidocaine into the monkey cerebral cortex.
authors.affiliation: Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA. tehovnik@wccf.mit.edu
authors.forename: E J
authors.initials: EJ
authors.lastname: Tehovnik
authors.forename: M A
authors.initials: MA
authors.lastname: Sommer
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D007263:Infusions, Parenteral / Q000295:instrumentation / Q000379:methods; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008253:Macaca mulatta; D008845:Microinjections / Q000295:instrumentation / Q000379:methods; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011336:Probability; D013997:Time Factors
chemical_list: D008012:Lidocaine