OBJECTIVE: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. METHODS: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 micros were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. RESULTS: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. CONCLUSIONS: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. SIGNIFICANCE: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.
OBJECTIVE: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epilepticpatients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. METHODS: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epilepticpatients. MN stimulations of 100 micros were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. RESULTS: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. CONCLUSIONS: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. SIGNIFICANCE: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.
Authors: Ana Maria Cebolla; Caty De Saedeleer; Ana Bengoetxea; Françoise Leurs; Costantino Balestra; Pablo d'Alcantara; Ernesto Palmero-Soler; Bernard Dan; Guy Cheron Journal: Hum Brain Mapp Date: 2009-05 Impact factor: 5.038
Authors: Carlos Trenado; Saskia Elben; Lena Friggemann; Sonja Gruhn; Stefan Jun Groiss; Jan Vesper; Alfons Schnitzler; Lars Wojtecki Journal: PLoS One Date: 2017-01-12 Impact factor: 3.240
Authors: Guy Cheron; Ana Maria Cebolla; Caty De Saedeleer; Ana Bengoetxea; Françoise Leurs; Axelle Leroy; Bernard Dan Journal: BMC Neurosci Date: 2007-09-18 Impact factor: 3.288