Send to

Choose Destination
See comment in PubMed Commons below
J Comp Neurol. 2009 Jul 10;515(2):231-42. doi: 10.1002/cne.22050.

Development of auditory thalamocortical connections in the pallid bat, Antrozous pallidus.

Author information

Department of Psychology, University of California, Riverside, California 92521, USA.


Auditory thalamocortical connections are organized as parallel pathways originating in various nuclei of the medial geniculate body (MGB). The development of these pathways has not been studied. Therefore it remains unclear whether thalamocortical connections segregate before the onset of hearing or whether refinement of exuberant thalamocortical connections occurs following hearing onset. We studied this issue in the pallid bat. In adult pallid bats, parallel thalamocortical pathways represent two different sounds used in two different behaviors. The suprageniculate (SG) nucleus of the dorsal division of the MGB (MGBd) projects to a high-frequency cortical region selective for the echolocation calls, but not to a low-frequency cortical region sensitive to noise transients used in the localization of prey. Conversely, the ventral division (MGBv) projects to the low-frequency, but not the high-frequency, cortical region. Here we studied the development of these parallel pathways. Based on retrograde tracer injections in electrophysiologically characterized cortical loci, we show that there is an asymmetrical overlap in projection patterns from postnatal (P) day 15-60. The low-frequency region receives extensive input from both the SG and the MGBv. In contrast, the high-frequency region receives the great majority of its input from the SG, as in adults, whereas projections from the MGBv appear to make only a minor contribution, if any. By P150, these pathways are segregated and adult-like. These data suggest that these anatomically segregated pathways arise through postnatal refinement of initially overlapping connections.

[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center