A microchannel device tailored to laser axotomy and long-term microelectrode array electrophysiology of functional regeneration

Lab on a Chip ◽  
2015 ◽  
Vol 15 (24) ◽  
pp. 4578-4590 ◽  
Author(s):  
Rouhollah Habibey ◽  
Asiyeh Golabchi ◽  
Shahrzad Latifi ◽  
Francesco Difato ◽  
Axel Blau
Keyword(s):  
Neuronal Network ◽  
Microelectrode Array ◽  
Laser Microdissection ◽  
Axonal Injury ◽  
Multielectrode Array ◽  
Pdms Microchannel ◽  
Functional Regeneration ◽  
Microchannel Device ◽  
Network Morphology

We present a PDMS microchannel device compatible with multielectrode array electrophysiology and laser microdissection for selected axonal injury and long-term access to compartmentalized neuronal network morphology and activity.

scholarly journals Long-term non-invasive interrogation of human dorsal root ganglion neuronal cultures on an integrated microfluidic multielectrode array platform

The Analyst ◽  
2016 ◽  
Vol 141 (18) ◽  
pp. 5346-5357 ◽  
Author(s):  
H. A. Enright ◽  
S. H. Felix ◽  
N. O. Fischer ◽  
E. V. Mukerjee ◽  
D. Soscia ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Microelectrode Array ◽  
Multielectrode Array ◽  
Neuronal Cultures ◽  
Primary Neurons ◽  
Chemical Exposures ◽  
Non Invasive ◽  
Array Platform

Electrophysiology measurements from human primary neurons after repeated chemical exposures are enabled with an integrated microfluidic and microelectrode array device.

scholarly journals Functional regeneration and repair of tendons using biomimetic scaffolds loaded with recombinant periostin

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yu Wang ◽  
Shanshan Jin ◽  
Dan Luo ◽  
Danqing He ◽  
Chunyan Shi ◽  
...  
Keyword(s):  
Progenitor Cell ◽  
Transcriptional Profiling ◽  
Collagen Scaffold ◽  
Defect Model ◽  
Tendon Regeneration ◽  
Biomimetic Scaffolds ◽  
Functional Regeneration

AbstractTendon injuries disrupt the balance between stability and mobility, causing compromised functions and disabilities. The regeneration of mature, functional tendons remains a clinical challenge. Here, we perform transcriptional profiling of tendon developmental processes to show that the extracellular matrix-associated protein periostin (Postn) contributes to the maintenance of tendon stem/progenitor cell (TSPC) functions and promotes tendon regeneration. We show that recombinant periostin (rPOSTN) promotes the proliferation and stemness of TSPCs, and maintains the tenogenic potentials of TSPCs in vitro. We also find that rPOSTN protects TSPCs against functional impairment during long-term passage in vitro. For in vivo tendon formation, we construct a biomimetic parallel-aligned collagen scaffold to facilitate TSPC tenogenesis. Using a rat full-cut Achilles tendon defect model, we demonstrate that scaffolds loaded with rPOSTN promote endogenous TSPC recruitment, tendon regeneration and repair with native-like hierarchically organized collagen fibers. Moreover, newly regenerated tendons show recovery of mechanical properties and locomotion functions.

scholarly journals Soft-wired long-term memory in a natural recurrent neuronal network

2020 ◽  
Author(s):  
Miguel A. Casal ◽  
Santiago Galella ◽  
Oscar Vilarroya ◽  
Jordi Garcia-Ojalvo
Keyword(s):  
Neuronal Network ◽  
Neuronal Networks ◽  
Initial Conditions ◽  
Permutation Entropy ◽  
Long Term Memory ◽  
Term Memory ◽  
C Elegans ◽  
Living Organisms ◽  
Recurrent Connections

Neuronal networks provide living organisms with the ability to process information. They are also characterized by abundant recurrent connections, which give rise to strong feed-back that dictates their dynamics and endows them with fading (short-term) memory. The role of recurrence in long-term memory, on the other hand, is still unclear. Here we use the neuronal network of the roundworm C. elegans to show that recurrent architectures in living organisms can exhibit long-term memory without relying on specific hard-wired modules. A genetic algorithm reveals that the experimentally observed dynamics of the worm’s neuronal network exhibits maximal complexity (as measured by permutation entropy). In that complex regime, the response of the system to repeated presentations of a time-varying stimulus reveals a consistent behavior that can be interpreted as soft-wired long-term memory.A common manifestation of our ability to remember the past is the consistence of our responses to repeated presentations of stimuli across time. Complex chaotic dynamics is known to produce such reliable responses in spite of its characteristic sensitive dependence on initial conditions. In neuronal networks, complex behavior is known to result from a combination of (i) recurrent connections and (ii) a balance between excitation and inhibition. Here we show that those features concur in the neuronal network of a living organism, namely C. elegans. This enables long-term memory to arise in an on-line manner, without having to be hard-wired in the brain.

scholarly journals Accuracy in prediction of long-term functional outcome in patients with traumatic axonal injury: a comparison of MRI scales

Brain Injury ◽  
2020 ◽  
Vol 34 (5) ◽  
pp. 595-601 ◽  
Author(s):  
Marleen Maria van Eijck ◽  
Martin Willy Herklots ◽  
Jo Peluso ◽  
Guus Geurt Schoonman ◽  
Annemarie Wilhelma Oldenbeuving ◽  
...  
Keyword(s):  
Functional Outcome ◽  
Axonal Injury ◽  
Traumatic Axonal Injury

scholarly journals Dynamic Transitions in Neuronal Network Firing Sustained by Abnormal Astrocyte Feedback

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yangyang Yu ◽  
Zhixuan Yuan ◽  
Yongchen Fan ◽  
Jiajia Li ◽  
Ying Wu
Keyword(s):  
Neuronal Network ◽  
Epileptic Seizures ◽  
Neuronal Firing ◽  
Intensity Increase ◽  
Abnormal State ◽  
Synchronous Firing ◽  
Connection Probability ◽  
Neuronal Network Model ◽  
Hippocampal Ca3

Astrocytes play a crucial role in neuronal firing activity. Their abnormal state may lead to the pathological transition of neuronal firing patterns and even induce seizures. However, there is still little evidence explaining how the astrocyte network modulates seizures caused by structural abnormalities, such as gliosis. To explore the role of gliosis of the astrocyte network in epileptic seizures, we first established a direct astrocyte feedback neuronal network model on the basis of the hippocampal CA3 neuron-astrocyte model to simulate the condition of gliosis when astrocyte processes swell and the feedback to neurons increases in an abnormal state. We analyzed the firing pattern transitions of the neuronal network when astrocyte feedback starts to change via increases in both astrocyte feedback intensity and the connection probability of astrocytes to neurons in the network. The results show that as the connection probability and astrocyte feedback intensity increase, neuronal firing transforms from a nonepileptic synchronous firing state to an asynchronous firing state, and when astrocyte feedback starts to become abnormal, seizure-like firing becomes more severe and synchronized; meanwhile, the synchronization area continues to expand and eventually transforms into long-term seizure-like synchronous firing. Therefore, our results prove that astrocyte feedback can regulate the firing of the neuronal network, and when the astrocyte network develops gliosis, there will be an increase in the induction rate of epileptic seizures.

scholarly journals Hockey Concussion Education Project, Part 2. Microstructural white matter alterations in acutely concussed ice hockey players: a longitudinal free-water MRI study

2014 ◽  
Vol 120 (4) ◽  
pp. 873-881 ◽  
Author(s):  
Ofer Pasternak ◽  
Inga K. Koerte ◽  
Sylvain Bouix ◽  
Eli Fredman ◽  
Takeshi Sasaki ◽  
...  
Keyword(s):  
White Matter ◽  
Extracellular Space ◽  
Axonal Injury ◽  
Free Water ◽  
Ice Hockey ◽  
Microstructural Alterations ◽  
Hockey Players ◽  
Before And After ◽  
The Brain

Object Concussion is a common injury in ice hockey and a health problem for the general population. Traumatic axonal injury has been associated with concussions (also referred to as mild traumatic brain injuries), yet the pathological course that leads from injury to recovery or to long-term sequelae is still not known. This study investigated the longitudinal course of concussion by comparing diffusion MRI (dMRI) scans of the brains of ice hockey players before and after a concussion. Methods The 2011–2012 Hockey Concussion Education Project followed 45 university-level ice hockey players (both male and female) during a single Canadian Interuniversity Sports season. Of these, 38 players had usable dMRI scans obtained in the preseason. During the season, 11 players suffered a concussion, and 7 of these 11 players had usable dMRI scans that were taken within 72 hours of injury. To analyze the data, the authors performed free-water imaging, which reflects an increase in specificity over other dMRI analysis methods by identifying alterations that occur in the extracellular space compared with those that occur in proximity to cellular tissue in the white matter. They used an individualized approach to identify alterations that are spatially heterogeneous, as is expected in concussions. Results Paired comparison of the concussed players before and after injury revealed a statistically significant (p < 0.05) common pattern of reduced free-water volume and reduced axial diffusivity and fractional anisotropy following elimination of freewater. These free-water–corrected measures are less affected by partial volumes containing extracellular water and are therefore more specific to processes that occur within the brain tissue. Fractional anisotropy was significantly increased, but this change was no longer significant following the free-water elimination. Conclusions Concussion during ice hockey games results in microstructural alterations that are detectable using dMRI. The alterations that the authors found suggest decreased extracellular space and decreased diffusivities in white matter tissue. This finding might be explained by axonal injury and/or by increased cellularity of glia cells. Even though these findings in and of themselves cannot determine whether the observed microstructural alterations are related to long-term pathology or persistent symptoms, they are important nonetheless because they establish a clearer picture of how the brain responds to concussion.

A new type of recording chamber with an easy-to-exchange microdrive array for chronic recordings in macaque monkeys

2011 ◽  
Vol 105 (6) ◽  
pp. 3092-3105 ◽  
Author(s):  
F. Orlando Galashan ◽  
Hanna C. Rempel ◽  
Anneke Meyer ◽  
Eva Gruber-Dujardin ◽  
Andreas K. Kreiter ◽  
...  
Keyword(s):  
Multielectrode Array ◽  
Histopathological Analysis ◽  
Recording Site ◽  
Macaque Monkeys ◽  
High Incidence ◽  
New Type ◽  
Bidirectional Movement ◽  
Aseptic Conditions ◽  
Awake Animal

In monkeys, long-term recordings with chronically implanted microelectrodes frequently suffer from a continuously decreasing probability to record single units or even small multiunit clusters. This problem is associated with two technical limitations of the available devices: first, restrictions for electrode movement, and second, absent possibility to exchange electrodes easily on a regular basis. Permitting to adjust the recording site and to use new recording tracks with proper electrodes may avoid these problems and make chronic more similar to acute recordings. Here, we describe a novel type of implant tackling this issue. It consists of a new type of recording chamber combined with an exchangeable multielectrode array that precisely fits into it. The multielectrode array is reversibly fixed to the chamber, and within a minute it can be exchanged against another array equipped with new electrodes at the awake animal. The array allows for bidirectional movement of six electrodes for a distance of up to 12 mm. The recording chamber enables hermetical isolation of the intracranial space, resulting in long-lasting aseptic conditions and reducing dural thickening to a minimum, as confirmed by microbiological and histopathological analysis. The device has a simple design and is both easy to produce and low in cost. Functionality has been tested in primary and secondary visual cortex of three macaque monkeys over a period of up to 15 mo. The results show that even after more than a year, single and multiunit responses can be obtained with high incidence.

Poly(dimethylsiloxane)-based microdevices for studying plant reproduction

2014 ◽  
Vol 42 (2) ◽  
pp. 320-324 ◽  
Author(s):  
Hideyuki Arata ◽  
Tetsuya Higashiyama
Keyword(s):  
Pollen Tube ◽  
Experimental Studies ◽  
Plant Reproduction ◽  
Plant Tissues ◽  
In Vitro Cultivation ◽  
Future Prospects ◽  
Experimental Approaches ◽  
Microchannel Device

Long-term holding and precise handling of growing plant tissues during in vitro cultivation has been a major hurdle for experimental studies related to plant development and reproduction. In the present review, we introduce two of our newly developed poly(dimethylsiloxane)-based microdevices: a T-shaped microchannel device for pollen tube chemoattraction and a microcage array for long-term live imaging of ovules. Their design, usage and advantages are described, and future prospects of experimental approaches to plant reproduction using such microdevices are discussed.

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