title: Reaction Time in a Visual 4-Choice Reaction Time Task: ERP Effects of Motor Preparation and Hemispheric Involvement.
abstract: Reaction time (RT), the most common measure of CNS efficiency, shows intra- and inter-individual variability. This may be accounted for by hemispheric specialization, individual neuroanatomy, and transient functional fluctuations between trials. To explore RT on these three levels, ERPs were measured in a visual 4-choice RT task with lateralized stimuli (left lateral, left middle, right middle, and right lateral) in 28 healthy right-handed subjects. We analyzed behavioral data, ERP microstates (MS), N1 and P3 components, and trial-by-trial variance. Across subjects, the N1 component was contralateral to the stimulation side. N1-MSs were stronger over the left hemisphere, and middle stimulation evoked stronger activation than lateral stimulation in both hemispheres. The P3 was larger for the right visual field stimulation. RTs were shorter for the right visual hemifield stimulation/right hand responses. Within subjects, covariance analysis of single trial ERPs with RTs showed consistent lateralized predictors of RT over the motor cortex (MC) in the 112-248 ms interval. Decreased RTs were related to negativity over the MC contralateral to the stimulation side, an effect that could be interpreted as the lateralized readiness potential (LRP), and which was strongest for right side stimulation. The covariance analysis linking individual mean RTs and individual mean ERPs showed a frontal negativity and an occipital positivity correlating with decreased RTs in the 212-232 ms interval. We concluded that a particular RT is a composite measure that depends on the appropriateness of the motor preparation to a particular response and on stimulus lateralization that selectively involves a particular hemisphere.
authors.affiliation: Department of Neurobiology and Biophysics, Vilnius University, Ciurlionio 21/27, 03101, Vilnius, Lithuania. ingrida.antonova@gmail.com.|Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland. ingrida.antonova@gmail.com.
authors.forename: Ingrida
authors.initials: I
authors.lastname: Antonova
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland.
authors.forename: Claudia
authors.initials: C
authors.lastname: van Swam
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland.
authors.forename: Daniela
authors.initials: D
authors.lastname: Hubl
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.affiliation: Department of Neurobiology and Biophysics, Vilnius University, Ciurlionio 21/27, 03101, Vilnius, Lithuania.
authors.forename: Inga
authors.initials: I
authors.lastname: Griskova-Bulanova
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Koenig
mesh_terms: D000328:Adult; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D010775:Photic Stimulation; D011930:Reaction Time
keywords: Choice reaction time task; Interindividual and intraindividual variance; Lateralization; N1; P3; Visuospatial processing