Corticofugal reorganization of the midbrain tonotopic map in mice.
Previous studies have indicated that frequency maps (tonotopies) in mammalian auditory brain centers are plastic. Here, we examined this plasticity in the mouse auditory midbrain through focal stimulation of the primary auditory cortex. Cortical activation shifted midbrain frequency tunings toward the best frequencies of the stimulated cortical neurons if these were either higher or lower than the cortical ones. Such corticofugal adjustments appear to minimize the difference between cortical and collicular frequency tuning within the critical bandwidths of the auditory system. Consequently, the neural representation is enhanced for the frequencies to which the cortical neurons were tuned. Our data suggest that the auditory cortex reorganizes midbrain tonotopy on the basis of which cortical frequencies are stimulated, mostly probably through corticofugal projections.
Yan
J
J
Department of Physiology and Biophysics, Neuroscience Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, N.W., Calgary, Alberta, T2N 4N1, Canada.
Ehret
G
G
D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D004558:Electric Stimulation; D007245:Inferior Colliculi / Q000502:physiology*; D051379:Mice; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology