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 ex vivo 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.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.celrep.2020.02.044 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A psychophysically-tuned computational model of human primary visual cortex produces geometric optical illusions.
Curr Res Neurobiol
November 2024
The Sense Innovation and Research Center, Lausanne and Sion, Switzerland.
Article Synopsis
- Geometric optical illusions (GOIs) highlight mismatches between what we see and the actual physical stimuli, allowing researchers to explore how sensation and perception interact.
- A study conducted with 30 adults revealed that different physical properties of GOIs have varying effects on perceptual biases, and these effects can interact in complex ways.
- By combining psychophysics with computational modeling of the primary visual cortex, the researchers found that certain adjustments in neural parameters could replicate human perceptual biases, suggesting that different physical attributes work together to create a GOI and offering insights into the mechanisms behind perception.
Noninvasive focal transgene delivery with viral neuronal tracers in the marmoset monkey.
Cell Rep Methods
February 2024
Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address:
We establish a reliable method for selectively delivering adeno-associated viral vectors (AAVs) across the blood-brain barrier (BBB) in the marmoset without the need for neurosurgical injection. We focally perturbed the BBB (∼1 × 2 mm) in area 8aD of the frontal cortex in four adult marmoset monkeys using low-intensity transcranial focused ultrasound aided by microbubbles. Within an hour of opening the BBB, either AAV2 or AAV9 was delivered systemically via tail-vein injection.
View Article and Find Full Text PDFDiverse axonal morphologies of individual callosal projection neurons reveal new insights into brain connectivity.
Curr Opin Neurobiol
February 2024
Department of Neuroscience, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA. Electronic address:
In the mature brain, functionally distinct areas connect to specific targets, mediating network activity required for function. New insights are still occurring regarding how specific connectivity occurs in the developing brain. Decades of work have revealed important insights into the molecular and genetic mechanisms regulating cell type specification in the brain.
View Article and Find Full Text PDFNormal connectivity of thalamorecipient networks in barrel equivalents of the reeler cortex.
Cereb Cortex
June 2023
Institute for Neuroanatomy, University Medical Center, Georg-August-University Göttingen, Göttingen 37075, Germany.
The reeler mouse mutant has long served as a primary model to study the development of cortical layers, which is governed by the extracellular glycoprotein reelin secreted by Cajal-Retzius cells. Because layers organize local and long-range circuits for sensory processing, we investigated whether intracortical connectivity is compromised by reelin deficiency in this model. We generated a transgenic reeler mutant (we used both sexes), in which layer 4-fated spiny stellate neurons are labeled with tdTomato and applied slice electrophysiology and immunohistochemistry with synaptotagmin-2 to study the circuitry between the major thalamorecipient cell types, namely excitatory spiny stellate and inhibitory fast-spiking (putative basket) cells.
View Article and Find Full Text PDFCDKL5 sculpts functional callosal connectivity to promote cognitive flexibility.
Mol Psychiatry
June 2024
F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
Functional and structural connectivity alterations in short- and long-range projections have been reported across neurodevelopmental disorders (NDD). Interhemispheric callosal projection neurons (CPN) represent one of the major long-range projections in the brain, which are particularly important for higher-order cognitive function and flexibility. However, whether a causal relationship exists between interhemispheric connectivity alterations and cognitive deficits in NDD remains elusive.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!