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Seizure-related automatic locomotion triggered by intracerebral electrical stimulation Volume 10, numéro 4, December 2008

Figure 1 Stereotaxic schemes of SEEG exploration (upper panels; right lateral and frontal views of the skull) and MRI images illustrating the trajectories of depth cerebral electrodes. For each electrode, the lowest numbers indicate the inner contacts, whereas the highest indicates the outer contacts.Left MRI sagittal slice: the trajectory of electrodes J, K, Z (lines) and the anterio-posterior location of electrodes G (point), O, E, H, F and M (crosses) are shown. Right MRI coronal slice: the trajectory of electrodes G (featuring 15 contacts) and Y (18 contacts) are illustrated; contacts G 6–7 (white square) and Y 7-8 (white cross) take place in the depth of the F2-F3 sulcus (Brodmann area 46).

Figure 2 SEEG recordings of the intracranial activity after electrical stimulation (HFS) of the depths of the F2-F3 sulcus.I) HFS of electrode H, contact 8-9 (3 mA / 5 s). (A) During the stimulation, the SEEG activity in most part of the derivations is covered from an artefact. (B) Follows a rapid, low voltage discharge (for 5 seconds) mainly involving the F2-F3 sulcus and the intermediate part of the medial frontal gyrus, the gyrus cinguli (genus and frontal part) and the orbital gyrus; among external derivations, the orbito-frontal gyrus and the frontal operculum. (C) Spike and wave (SW) sinusoidal discharge (8-9 Hz), diffuses to the former regions (more widely involving, the F2-F3 sulcus) and spreading also to the posterior part of the medial and superior frontal gyri. This activity abruptly stops after six seconds and is followed by an electrical depression or by rhythmic delta activity.II) HFS of electrode G, contact 6-7 (3 mA / 2.5 s). (A) A tonic flattening of the lesional portion of the F2-F3 sulcus and of the adjacent fronto-dorsal regions, also involving the anterior fronto-mesial derivations, appears at the beginning of the HFS. (B) About two seconds after the beginning of HFS, a rapid and recruiting, low-voltage discharge appears, widely involving the dorso-frontal structures (F2 and F3 gyri, frontal operculum and orbital gyrus), the medial portion of middle frontal gyrus and the frontal part of the gyrus cinguli (BA 24) (tonic discharge). (C) About five seconds later, this tonic rhythm is fragmented by a delta activity, producing a SW sinusoidal discharge, which stops abruptly after 11 seconds.The upper figures provide a schematization of the sites of HFS and of the topography of EEG spreading. At the bottom are summarized the concomitant clinical manifestations; in particular, it is noteworthy that forward locomotion coincides with the widespread, frontal recruiting discharge, and stops with its fragmentation into an SW rhythm.F: frontal; post: posterior; interm: intermediate; ant: anterior.