title: Spectral Signatures of Saccade Target Selection.
abstract: Action generation relies on a widely distributed network of brain areas. However, little is known about the spatiotemporal dynamics of neuronal activity in the network that gives rise to voluntary action in humans. Here, we used magnetoencephalography (MEG) and source analysis (n = 15, 7 female subjects) to investigate the spectral signatures of human cortical networks engaged in active and intrinsically motivated viewing behavior. We compared neuronal activity of externally cued saccades with saccades to freely chosen targets. For planning and execution of both saccade types, we found an increase in gamma band (~64-128 Hz) activity and a concurrent decrease in beta band (~12-32 Hz) activity in saccadic control areas, including the intraparietal sulcus and the frontal eye fields. Guided compared to voluntary actions were accompanied by stronger transient increases in the gamma and low frequency (<16 Hz) range immediately following the instructional cue. In contrast, action selection between competing alternatives was reflected by stronger sustained fronto-parietal gamma increases that occurred later in time and persisted until movement execution. This sustained enhancement for free target selection was accompanied by a spatially widespread reduction of lower frequency power (~8-45 Hz) in parietal and extrastriate areas. Our results suggest that neuronal population activity in the gamma frequency band in a distributed network of fronto-parietal areas reflects the intrinsically driven process of selection among competing behavioral alternatives.
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.|Institute of Cognitive Science, University of Osnabrück, Albrechtstraße 28, 49069, Osnabrück, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Carl
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.|Centre for Integrative Neuroscience, University of Tübingen, Paul-Ehrlich-Str. 17, 72076, Tübingen, Germany.|MEG-Center, University of Tübingen, 72076, Tübingen, Germany.
authors.forename: Joerg F
authors.initials: JF
authors.lastname: Hipp
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.|Institute of Cognitive Science, University of Osnabrück, Albrechtstraße 28, 49069, Osnabrück, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: König
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany. ak.engel@uke.de.
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Engel
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology*; D004585:Electrooculography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D013058:Mass Spectrometry; D009068:Movement; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Action selection; Cortical saccade generation; Frontal eye fields; Gamma band activity; Intraparietal sulcus; MEG