Systematic variation of potassium current amplitudes across the tonotopic axis of the rat medial nucleus of the trapezoid body

摘要: Many central auditory nuclei preserve the tonotopic organization of their afferent inputs, generating a frequency "map" across nucleus. In medial nucleus trapezoid body (MNTB) most neurons receive inputs corresponding to highest sounds and lateral have lowest characteristic frequencies. Whole-cell patch recording from MNTB principal in rat brainstem slices demonstrates voltage-gated outward potassium currents. Medial had larger total K+ current amplitudes than similar to-lateral gradients were observed for two subtypes distinguished by low high voltage activation thresholds. contrast, third conductance with an intermediate threshold slower kinetics showed inverse gradient (being smallest MNTB). The orthogonal axes did not exhibit (dorsal-to-ventral, or rostral-to-caudal). input resistance was unchanged MNTB, but slow capacitative component enhanced neurons. These data demonstrate that intrinsic properties are tuned axis so as promote shorter action potentials, faster firing therefore greater accuracy transmission information regions.