Abstract
Layer 6b (L6b), the deepest neocortical layer, projects to cortical targets and higher-order thalamus and is the only layer responsive to the wake-promoting neuropeptide orexin/hypocretin. These characteristics suggest that L6b can strongly modulate brain state, but projections to L6b and their influence remain unknown. Here, we examine the inputs to L6b exvivo in the mouse primary somatosensory cortex with rabies-based retrograde tracing and channelrhodopsin-assisted circuit mapping in brain slices. We find that L6b receives its strongest excitatory input from intracortical long-range projection neurons, including those in the contralateral hemisphere. In contrast, local intracortical input and thalamocortical input were significantly weaker. Moreover, our data suggest that L6b receives far less thalamocortical input than other cortical layers. L6b was most strongly inhibited by PV and SST interneurons. This study shows that L6b integrates long-range intracortical information and is not part of the traditional thalamocortical loop.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
