TY - JOUR
T1 - Short latency somatosensory evoked potentials recorded around the human upper brain-stem
AU - Urasaki, Eiichirou
AU - Uematsu, Sumio
AU - Lesser, Ronald P.
PY - 1993
Y1 - 1993
N2 - We analyzed the intracranial spatiotermporal distributions of the N18 component of short median nerve somatosensosry evoked potentials (SSEPs) in 3 patients with epilepsy. In these patients, depth electrodes were implanted bilaterally into the frontal and temporal lobes, with targets including the amygdala and hippocampus; the latter two targets are close to the upper pons and midbrain. In this study N18 was divided into the initial negative peak (N18a) and the following prolonged negativity (N18b). Mapping around the upper pons and midbrain showed that: (1) the amplitude of the first negativity, which coincided with scalp N18a, was larger contralateral to the side of stimulation, but showed no polarity change around the upper brain-stem; and (2) the second negativity, which was similar to scalp N18b, did show an amplitude difference or a polarity change. This wave appeared to reflect a positive-negative dipole directed in a dorso-ventral as well as dorso-lateral direction from the midbrain, where positivity arises from the dorsum of the midbrain, contralateral to the side of the stimulation. Recordings from depth electrode derivations oriented in a caudo-rostral direction suggest that N18a and N18b may in part reflect neural activity originating from the upper pons to midbrain region which projects to the rostral subcortical white matter of the frontal lobe as stationary peaks.
AB - We analyzed the intracranial spatiotermporal distributions of the N18 component of short median nerve somatosensosry evoked potentials (SSEPs) in 3 patients with epilepsy. In these patients, depth electrodes were implanted bilaterally into the frontal and temporal lobes, with targets including the amygdala and hippocampus; the latter two targets are close to the upper pons and midbrain. In this study N18 was divided into the initial negative peak (N18a) and the following prolonged negativity (N18b). Mapping around the upper pons and midbrain showed that: (1) the amplitude of the first negativity, which coincided with scalp N18a, was larger contralateral to the side of stimulation, but showed no polarity change around the upper brain-stem; and (2) the second negativity, which was similar to scalp N18b, did show an amplitude difference or a polarity change. This wave appeared to reflect a positive-negative dipole directed in a dorso-ventral as well as dorso-lateral direction from the midbrain, where positivity arises from the dorsum of the midbrain, contralateral to the side of the stimulation. Recordings from depth electrode derivations oriented in a caudo-rostral direction suggest that N18a and N18b may in part reflect neural activity originating from the upper pons to midbrain region which projects to the rostral subcortical white matter of the frontal lobe as stationary peaks.
KW - Depth recordings
KW - Median nerve stimulation
KW - N18 component
KW - Somatosensory evoked potentials
UR - http://www.scopus.com/inward/record.url?scp=0027418472&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027418472&partnerID=8YFLogxK
U2 - 10.1016/0168-5597(93)90060-3
DO - 10.1016/0168-5597(93)90060-3
M3 - Article
C2 - 7681759
AN - SCOPUS:0027418472
SN - 0168-5597
VL - 88
SP - 92
EP - 104
JO - Electroencephalography and Clinical Neurophysiology/ Evoked Potentials
JF - Electroencephalography and Clinical Neurophysiology/ Evoked Potentials
IS - 2
ER -