ORIGIN OF LARYNGEAL SENSORY-EVOKED POTENTIALS (LSEPS) IN THE CAT

Sensory-evoked potentials elicited by electrical stimulation of the superior laryngeal nerve were recorded at the dural surface on the cortex and the caudal medulla in anesthetized cats as a reflection of activities in the central afferent systems. These evoked potentials were named laryngeal sensory evoked potentials (LSEPs). LSEP was mainly composed of five components, N1BAR, N2BAR, N4BAR, N12BAR, and large biphasic potential (LBP). The peak latencies of these components were as follows: N1BAR, 1.09 +/- 0.18 ms: N2BAR, 1.93 +/- 0.19 ms; N4BAR, 3.97 +/- 0.19 ms; and N12BAR, 12.48 +/- 1.01 ms. LBP was a large component lasting from approximately 6 ms to 18 ms. The generator sources of these components were identified as follows: N1BAR, nodose ganglion; N2BAR, presynaptic potentials of the nucleus tractus of solitarius (NTS); N4BAR, NTS complex including the postsynaptic potentials; and N12BAR, activities of the frontal part of the orbital gyrus. The LBP was speculated to be generated from certain subcortical structures, such as the amygdala. the thalamus. the hypothalamus, and the basal ganglia.