Modulation of the receptive fields of midbrain neurons elicited by thalamic electrical stimulation through corticofugal feedback.
The ascending and descending projections of the central auditory system form multiple tonotopic loops. This study specifically examines the tonotopic pathway from the auditory thalamus to the auditory cortex and then to the auditory midbrain in mice. We observed the changes of receptive fields in the central nucleus of the inferior colliculus of the midbrain evoked by focal electrical stimulation of the ventral division of the medial geniculate body of the thalamus. The receptive field of an auditory neuron was characterized by five parameters: the best frequency, minimum threshold, bandwidth, size of receptive field, and average spike number. We found that focal thalamic stimulation changed the parametric values characterizing the recorded collicular receptive fields toward those characterizing the stimulated thalamic receptive fields. Cortical inactivation with muscimol prevented the development of the collicular plasticity induced by focal thalamic stimulation. Our data suggest that the intact colliculo-thalamo-cortico-collicular loops are important for the coordination of sound-guided plasticity in the central auditory system.
Wu
Yamin
Y
Department of Physiology and Biophysics, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Yan
Jun
J
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D001303:Auditory Cortex / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D001306:Auditory Pathways / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods*; D005246:Feedback / Q000502:physiology*; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D005829:Geniculate Bodies / Q000502:physiology / Q000528:radiation effects*; D007245:Inferior Colliculi / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009118:Muscimol / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects
D018755:GABA Agonists; D009118:Muscimol