Individual cortical neurons can selectively respond to specific environmental features, such as visual motion or faces. How this relates to the selectivity of the presynaptic network across cortical layers remains unclear. We used single-cell-initiated, monosynaptically restricted retrograde transsynaptic tracing with rabies viruses expressing GCaMP6s to image, in vivo, the visual motion-evoked activity of individual layer 2/3 pyramidal neurons and their presynaptic networks across layers in mouse primary visual cortex. Neurons within each layer exhibited similar motion direction preferences, forming layer-specific functional modules. In one-third of the networks, the layer modules were locked to the direction preference of the postsynaptic neuron, whereas for other networks the direction preference varied by layer. Thus, there exist feature-locked and feature-variant cortical networks.
The dentate gyrus is the main entry gate for cortical input to the hippocampus and one of the few brain areas where adult neurogenesis occurs. Several studies have shown that it is relatively difficult to induce synaptic plasticity in mature but not in newborn dentate granule cells. In the present work we have systematically addressed how classical protocols to induce synaptic plasticity affect action potential firing and intrinsic excitability in mature granule cells. We found that stimulation paradigms considered to be relevant for learning processes consistently modified the probability to generate action potentials in response to a given synaptic input in mature cells, in some paradigms even without any modification of synaptic strength. Collectively the results suggest that plasticity of intrinsic dendritic excitability has a lower induction-threshold than synaptic plasticity in mature granule cells and that this form of plasticity might be an important mechanism by which mature granule cells contribute to hippocampal function.
Technological resources for sustained local control of molecular effects within organs, cells, or subcellular regions are currently unavailable, even though such technologies would be pivotal for unveiling the molecular actions underlying collective mechanisms of neuronal networks, signaling systems, complex machineries, and organism development. We present a novel optopharmacological technology named molecular tattooing, which combines photoaffinity labeling with two-photon microscopy. Molecular tattooing covalently attaches a photoreactive bioactive compound to its target by two-photon irradiation without any systemic effects outside the targeted area, thereby achieving subfemtoliter, long-term confinement of target-specific effects in vivo. As we demonstrated in melanoma cells and zebrafish embryos, molecular tattooing is suitable for dissecting collective activities by the separation of autonomous and non-autonomous molecular processes in vivo ranging from subcellular to organism level. Since a series of drugs are available for molecular tattoo, the technology can be implemented by a wide range of fields in the life sciences.
2018 Neuroscience and Biological Optical imaging seminar will hold in Peking University Health Science Center from Nov 17-18。
Winter will give report in this seminar.
Title： Lightsheet ——from function to structure
Speaker：Winter Qi ( CEO of Twinter)
Time :PM 16:30 Nov 17th.
On 13 Nov, the first unit of Femto3D-AcoustoOptic microscope (AOD) from Femtoncis was successfully installed in Xinxiang Medical University.
On 26 Oct, the first unit of Inverted Lightsheet microscope (InVi-SPIM) from Luxendo was successfully installed in National Institute of Biological Sciences (NIBS), Beijing
2018 Xiamen International Brain Science& Symposium on Neurodegenerative Diseases from Dec 7-9 in Xia men, Fujian, China
We will like to invite you to find Two-photon and Lightsheet microscopy systems & new developments!
Recently,Tim Winter for national high-tech enterprise certification was approved, that is to say, since Dec 22, 2016, Tim Winter has become a national high-tech enterprise which was certificated by relevant departments of China.
Tim Winter’s certification as a national high-tech enterprise can not only further promotes company’s work of technology innovation up to a new level, but also plays an important role in bring powerful energy into the company. Our company will make persistent efforts and create brilliant future.
Tim Winter through ISO9001 quality system certification.
On May 16 2017, our company successfully passed the ISO9001 quality system certification.