Intracerebral dynamics of saccade generation in the human frontal eye field and supplementary eye field.
Recent functional imaging and electrical stimulation studies have localized in humans two frontal regions critical for the production of saccadic and anti-saccadic eye movements: the frontal and supplementary eye fields (FEF and SEF, respectively). We investigated the time course of their activations during the generation of pro- and anti-saccades from direct intracranial EEG recordings of three human epileptic patients. We found the preparation and the production of the saccades to be coincident with focal and transient increases of EEG power above 60 Hz. Those were produced in very specific brain sites distributed in the FEF and the SEF (as identified by previous human studies at a coarser time resolution). Furthermore, the spatio-temporal resolution of those recordings turned out to be sufficient to discriminate anatomically between several types of neural responses, determined either by the visual or by the motor components of the saccade tasks, and within this second category of responses, between some associated with the preparation of the saccades and others associated with their execution. Altogether, this study provides the first evidence of high-frequency neural responses in the generation of saccades in humans, and provides a firm basis for other studies detailing further the functional organization of the human oculomotor system at this level of spatial and temporal resolution.
Lachaux
Jean-Philippe
JP
Mental Processes and Brain Activation, Unite 280, INSERM 151, cours Albert Thomas, 69424 Lyon cedex 03, France. lachaux@lyon.inserm.fr
Hoffmann
Dominique
D
Minotti
Lorella
L
Berthoz
Alain
A
Kahane
Philippe
P
D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000601:surgery; D005071:Evoked Potentials / Q000502:physiology; D005583:Fourier Analysis; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D009434:Neural Pathways / Q000503:physiopathology; D009802:Oculomotor Nerve / Q000503:physiopathology; D009949:Orientation / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D014796:Visual Perception / Q000502:physiology