Topographic representation of the receptor surface is a fundamental feature of sensory cortical organization. This is imparted by the thalamus, which relays information from the periphery to the cortex. To better understand the rules governing thalamocortical connectivity and the origin of cortical maps, we used in vivo two-photon calcium imaging to characterize the properties of thalamic axons innervating different layers of mouse auditory cortex. Although tonotopically organized at a global level, we found that the frequency selectivity of individual thalamocortical axons is surprisingly heterogeneous, even in layers 3b/4 of the primary cortical areas, where the thalamic input is dominated by the lemniscal projection. We also show that thalamocortical input to layer 1 includes collaterals from axons innervating layers 3b/4 and is largely in register with the main input targeting those layers. Such locally varied thalamocortical projections may be useful in enabling rapid contextual modulation of cortical frequency representations.
- Andrew J King
- Yves Weissenberger
- Sebastian A Vasquez-Lopez
- Michael Lohse
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Christine Petit, Reviewing Editor, Institut Pasteur, France
- Received: February 11, 2017
- Accepted: September 8, 2017
- Accepted Manuscript published: September 11, 2017 (version 1)
© 2017, Vasquez-Lopez et al.
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