title: The free choice whether or not to respond after stimulus presentation.
abstract: The concept of 'willed' actions has attracted attention during the last few years. Free choices have been associated with activations on the medial frontal surface, the dorsolateral prefrontal cortex and the parietal lobe. Self-paced movements and free selection between various motor responses were typically used to investigate voluntary behavior. The aim of the present study was to determine neural correlates of voluntary motor responses and the voluntary inhibition of motor responses in a group of healthy subjects. Hence, a go/nogo/voluntary selection paradigm was used. In the voluntary selection condition subjects decided freely whether or not to respond with a button press after stimulus presentation. Functional MRI data and event-related potentials were acquired simultaneously in order to reliably investigate spatial and temporal characteristics of these responses. The results showed decision-related enhanced neural responses predominantly in the medial frontal gyrus/supplementary motor area, lateral frontal brain regions and the inferior parietal gyrus. Additional activations associated with voluntary movements were detected in the frontal eye field as well as brain regions directly linked to motor responses (e.g. somatosensory cortical areas). Altogether, decision processes were shown to be relatively independent of the kind of response chosen.
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University Munich, Munich, Germany. susanne.karch@med.uni-muenchen.de
authors.forename: Susanne
authors.initials: S
authors.lastname: Karch
authors.forename: Christoph
authors.initials: C
authors.lastname: Mulert
authors.forename: Tobias
authors.initials: T
authors.lastname: Thalmeier
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lutz
authors.forename: Gregor
authors.initials: G
authors.lastname: Leicht
authors.forename: Thomas
authors.initials: T
authors.lastname: Meindl
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Möller
authors.forename: Lorenz
authors.initials: L
authors.lastname: Jäger
authors.forename: Oliver
authors.initials: O
authors.lastname: Pogarell
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology; D002755:Choice Behavior / Q000502:physiology*; D003657:Decision Making / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009068:Movement / Q000502:physiology*; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D014836:Volition / Q000502:physiology*; D055815:Young Adult