Topography and physiology of ascending streams in the auditory tectothalamic pathway.
Auditory information is relayed from the cochlea along parallel pathways and reaches the inferior colliculus (IC) and the medial geniculate body (MGB) en route to the cortex. Although the ascending tectothalamic pathway to the ventral division of the MGB is regarded as a high-fidelity information-bearing channel, the roles of the pathways to the dorsal and medial divisions are more opaque. Here, we show fundamental differences between these ascending pathways using an in vitro slice preparation. Using photostimulation, we found three main patterns of input (excitatory, inhibitory, and mixed) that differed in each pathway. Furthermore, electrical stimulation of the central nucleus of the IC evoked a depressing response in the MGB with no metabotropic glutamate (mGlu) receptor component, whereas stimulation of the lateral cortex of the IC evoked a facilitating response with an mGlu receptor component. These data suggest that the ascending tectothalamic pathways are functionally distinct from one another.
Lee
Charles C
CC
Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA. clee@bsd.uchicago.edu
Sherman
S Murray
SM
D000818:Animals; D001306:Auditory Pathways / Q000033:anatomy & histology / Q000502:physiology; D018756:GABA Antagonists / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009474:Neurons / Q000166:cytology / Q000502:physiology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D011963:Receptors, GABA-A / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D013477:Superior Colliculi / Q000033:anatomy & histology / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology; D013788:Thalamus / Q000033:anatomy & histology / Q000502:physiology
D018756:GABA Antagonists; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B