scholarly journals Semi-intact ex vivo approach to investigate spinal somatosensory circuits

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Junichi Hachisuka ◽  
Kyle M Baumbauer ◽  
Yu Omori ◽  
Lindsey M Snyder ◽  
H Richard Koerber ◽  
...  

The somatosensory input that gives rise to the perceptions of pain, itch, cold and heat are initially integrated in the superficial dorsal horn of the spinal cord. Here, we describe a new approach to investigate these neural circuits in mouse. This semi-intact somatosensory preparation enables recording from spinal output neurons, while precisely controlling somatosensory input, and simultaneously manipulating specific populations of spinal interneurons. Our findings suggest that spinal interneurons show distinct temporal and spatial tuning properties. We also show that modality selectivity — mechanical, heat and cold — can be assessed in both retrogradely labeled spinoparabrachial projection neurons and genetically labeled spinal interneurons. Finally, we demonstrate that interneuron connectivity can be determined via optogenetic activation of specific interneuron subtypes. This new approach may facilitate key conceptual advances in our understanding of the spinal somatosensory circuits in health and disease.

Author(s):  
Hong Lei ◽  
Lynne A. Oland ◽  
Jeffery A. Riffell ◽  
Aaron Beyerlein ◽  
John G. Hildebrand

Olfactory circuits of all animals face a common challenge of extracting meaningful odor cues from background odors. This chapter summarizes what the authors have learned from their ongoing work toward the goal of understanding how the neural circuits in a moth’s antennal lobe (AL) determine diverse physiological responses that ultimately mediate the animal’s natural behavior. The text describes the different types of cellular elements that participate in the glomerular circuitry, focuses on the functional organization of these elements, and attempts to explain observed physiological responses in the context of behavior using the understood operating principles of the AL circuits. For convenience, the connections from the perspective of the main output neurons of the circuitry, uniglomerular projection neurons (uPNs), are described.


2021 ◽  
Vol 72 ◽  
pp. 105099
Author(s):  
Lorena Polloni ◽  
Fernanda Van Petten Vasconcelos Azevedo ◽  
Samuel Cota Teixeira ◽  
Eloá Moura ◽  
Tassia Rafaela Costa ◽  
...  

Author(s):  
Sébastien Baekelandt ◽  
Valérie Cornet ◽  
Syaghalirwa.N.M. Mandiki ◽  
Lambert Jérôme ◽  
Dubois Mickaël ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 132
Author(s):  
Johanna Simon ◽  
Gabor Kuhn ◽  
Michael Fichter ◽  
Stephan Gehring ◽  
Katharina Landfester ◽  
...  

Understanding the behavior of nanoparticles upon contact with a physiological environment is of urgent need in order to improve their properties for a successful therapeutic application. Most commonly, the interaction of nanoparticles with plasma proteins are studied under in vitro conditions. However, this has been shown to not reflect the complex situation after in vivo administration. Therefore, here we focused on the investigation of magnetic nanoparticles with blood proteins under in vivo conditions. Importantly, we observed a radically different proteome in vivo in comparison to the in vitro situation underlining the significance of in vivo protein corona studies. Next to this, we found that the in vivo corona profile does not significantly change over time. To mimic the in vivo situation, we established an approach, which we termed “ex vivo” as it uses whole blood freshly prepared from an animal. Overall, we present a comprehensive analysis focusing on the interaction between nanoparticles and blood proteins under in vivo conditions and how to mimic this situation with our ex vivo approach. This knowledge is needed to characterize the true biological identity of nanoparticles.


2007 ◽  
Vol 05 (01n02) ◽  
pp. 89-95
Author(s):  
J. R. CROCA

Orthodox quantum mechanics has another implicit postulate stating that temporal and spatial frequencies of the Planck–Einstein and de Broglie formulas can only be linked with the infinite, in time and space, harmonic plane waves of Fourier analysis. From this assumption, nonlocality either in space and time follows directly. This is what is called Fourier Ontology. In order to build nonlinear causal and local quantum physics, it is necessary to reject Fourier ontology and accept that in certain cases a finite wave may have a well defined frequency. Now the mathematical tool to describe this new approach is wavelet local analysis. This more general nonlinear local and causal quantum physics, in the limit of the linear approximation, contains formally orthodox quantum mechanics as a particular case.


2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Andrius Serva ◽  
Christoph Claas ◽  
Vytaute Starkuviene

In the last years miRNAs have increasingly been recognised as potent posttranscriptional regulators of gene expression. Possibly, miRNAs exert their action on virtually any biological process by simultaneous regulation of numerous genes. The importance of miRNA-based regulation in health and disease has inspired research to investigate diverse aspects of miRNA origin, biogenesis, and function. Despite the recent rapid accumulation of experimental data, and the emergence of functional models, the complexity of miRNA-based regulation is still far from being well understood. In particular, we lack comprehensive knowledge as to which cellular processes are regulated by which miRNAs, and, furthermore, how temporal and spatial interactions of miRNAs to their targets occur. Results from large-scale functional analyses have immense potential to address these questions. In this review, we discuss the latest progress in application of high-content and high-throughput functional analysis for the systematic elucidation of the biological roles of miRNAs.


2010 ◽  
Vol 196 ◽  
pp. S232-S233
Author(s):  
P. Pinton ◽  
D. Tsybulskyy ◽  
B. Joly ◽  
N. Bourges-Abella ◽  
I.P. Oswald ◽  
...  

2020 ◽  
Author(s):  
Krishnakanth Kondabolu ◽  
Natalie M. Doig ◽  
Olaoluwa Ayeko ◽  
Bakhtawer Khan ◽  
Alexandra Torres ◽  
...  

AbstractThe striatum and subthalamic nucleus (STN) are considered to be the primary input nuclei of the basal ganglia. Projection neurons of both striatum and STN can extensively interact with other basal ganglia nuclei, and there is growing anatomical evidence of direct axonal connections from the STN to striatum. There remains, however, a pressing need to elucidate the organization and impact of these subthalamostriatal projections in the context of the diverse cell types constituting the striatum. To address this, we carried out monosynaptic retrograde tracing from genetically-defined populations of dorsal striatal neurons in adult male and female mice, quantifying the connectivity from STN neurons to spiny projection neurons, GABAergic interneurons, and cholinergic interneurons. In parallel, we used a combination of ex vivo electrophysiology and optogenetics to characterize the responses of a complementary range of dorsal striatal neuron types to activation of STN axons. Our tracing studies showed that the connectivity from STN neurons to striatal parvalbumin-expressing interneurons is significantly higher (~ four-to eight-fold) than that from STN to any of the four other striatal cell types examined. In agreement, our recording experiments showed that parvalbumin-expressing interneurons, but not the other cell types tested, commonly exhibited robust monosynaptic excitatory responses to subthalamostriatal inputs. Taken together, our data collectively demonstrate that the subthalamostriatal projection is highly selective for target cell type. We conclude that glutamatergic STN neurons are positioned to directly and powerfully influence striatal activity dynamics by virtue of their enriched innervation of GABAergic parvalbumin-expressing interneurons.


2022 ◽  
Author(s):  
Bridget A Matikainen-Ankney ◽  
Alex A Legaria ◽  
Yvan M Vachez ◽  
Caitlin A Murphy ◽  
Yiyan A Pan ◽  
...  

Obesity is a chronic relapsing disorder that is caused by an excess of caloric intake relative to energy expenditure. In addition to homeostatic feeding mechanisms, there is growing recognition of the involvement of food reward and motivation in the development of obesity. However, it remains unclear how brain circuits that control food reward and motivation are altered in obese animals. Here, we tested the hypothesis that signaling through pro-motivational circuits in the core of the nucleus accumbens (NAc) is enhanced in the obese state, leading to invigoration of food seeking. Using a novel behavioral assay that quantifies physical work during food seeking, we confirmed that obese mice work harder than lean mice to obtain food, consistent with an increase in the relative reinforcing value of food in the obese state. To explain this behavioral finding, we recorded neural activity in the NAc core with both in vivo electrophysiology and cell-type specific calcium fiber photometry. Here we observed greater activation of D1-receptor expressing NAc spiny projection neurons (NAc D1SPNs) during food seeking in obese mice relative to lean mice. With ex vivo slice physiology we identified both pre- and post-synaptic mechanisms that contribute to this enhancement in NAc D1SPN activity in obese mice. Finally, blocking synaptic transmission from D1SPNs decreased physical work during food seeking and attenuated high-fat diet-induced weight gain. These experiments demonstrate that obesity is associated with a selective increase in the activity of D1SPNs during food seeking, which enhances the vigor of food seeking. This work also establishes the necessity of D1SPNs in the development of diet-induced obesity, identifying a novel potential therapeutic target.


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