title: Hippocampal negative event-related potential recorded in humans during a simple sensorimotor task occurs independently of motor execution.
abstract: A hippocampal-prominent event-related potential (ERP) with a peak latency at around 450 ms is consistently observed as a correlate of hippocampal activity during various cognitive tasks. Some intracranial EEG studies demonstrated that the amplitude of this hippocampal potential was greater in response to stimuli requiring an overt motor response, in comparison with stimuli for which no motor response is required. These findings could indicate that hippocampal-evoked activity is related to movement execution as well as stimulus evaluation and associated memory processes. The aim of the present study was to investigate the temporal relationship between the hippocampal negative potential latency and motor responses. We analyzed ERPs recorded with 22 depth electrodes implanted into the hippocampi of 11 epileptic patients. Subjects were instructed to press a button after the presentation of a tone. All investigated hippocampi generated a prominent negative ERP peaking at ~420 ms. In 16 from 22 cases, we found that the ERP latency did not correlate with the reaction time; in different subjects, this potential could either precede or follow the motor response. Our results indicate that the hippocampal negative ERP occurs independently of motor execution. We suggest that hippocampal-evoked activity, recorded in a simple sensorimotor task, is related to the evaluation of stimulus meaning within the context of situation.
authors.affiliation: Department of Physiology, Medical Faculty, Masaryk University, Brno, Czech Republic; CEITEC, Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Roman
authors.forename: Milan
authors.initials: M
authors.lastname: Brázdil
authors.forename: Jan
authors.initials: J
authors.lastname: Chládek
authors.forename: Ivan
authors.initials: I
authors.lastname: Rektor
authors.forename: Pavel
authors.initials: P
authors.lastname: Jurák
authors.forename: Miroslav
authors.initials: M
authors.lastname: Světlák
authors.forename: Alena
authors.initials: A
authors.lastname: Damborská
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Shaw
authors.forename: Miloslav
authors.initials: M
authors.lastname: Kukleta
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D018709:Statistics, Nonparametric
keywords: ERP latency; auditory task; hippocampus; intracranial recordings; motor response