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Tauber, J.

Publications and source records attributed to Tauber, J..

4 recordsLinked to original sources

Plant actin networks are rapid mechano-adaptive scaffolds

The actin cytoskeleton is among the most highly conserved eukaryotic structures. In animal cells, actin plays a key role in mechanobiology, serving as a structural scaffold that shapes cellular mechanics and a mechanoresponsive network that reorganizes in response to mechanical cues. In plants, these roles are generally attributed to the cell wall and the microtubule cytoskeleton. This leaves the role of plant actin in mechanical responses largely unclear. Here, we ask whether a key actin feature that is essential for animal mechanobiology may also be conserved in plants. We use quantitative live-cell imaging and quantitative image analysis to show that plant actin networks are rapidly mechano-responsive. We find a quantitative correlation between the cellular distribution of cortical actin networks and cellular deformations induced by laser ablation. This process is rapid and completes within 2-4 minutes. We propose that this is an intrinsic physical property of crosslinked filamentous networks, as these findings can be reproduced in a physical model that lacks biological regulation. Moreover, actin networks also respond to different types of mechanical stresses: both osmotic treatment and squeezing lead to distinct changes in actin organization, distribution, and dynamics. Our findings show that plant actin networks form mechano-adaptive scaffolds that sense mechanical deformations and reorganize in response within just a few minutes. This gives rise to a picture of plants having a two-geared cytoskeletal mechano-response system in which microtubules mediate slow responses to subtle developmental stresses, whereas actin provides a rapid response to large and potentially damaging deformations.

plant biology↗

Reversible superdeformability of hiPSC epithelial cortinoids

Epithelial cortinoids, fluid filled shells formed from induced pluripotent stem cells (iPSCs), must accommodate large deformations during growth and morphogenesis. Using inflation-deflation assays and high-resolution imaging, we find that these fluid-filled shells are weakly-pressurized and achieve extreme deformability through reversible soft modes of deformation accommodated by the cytoskeleton. We show that cytoskeletal elements such as actin localized along lateral cell edges undergo tilt and bend instabilities that buffer mechanical load by decoupling apico-basal stretching from lateral extension. These reversible instabilities act as elastic safety valves, permitting large shape changes without loss of epithelial hydraulic and topological integrity. A minimal theoretical and computational model demonstrates how tilt and bend reduce effective resistance to radial thinning and explains the observed pressure-strain softening. Thus, iPSC shells exploit reversible cytoskeletal instabilities as mechanical buffers, enabling robust tolerance of large deformations in developing epithelia.

biophysics↗

Spike-wave discharges during low-current thalamic deep brain stimulation in mice

BackgroundDeep brain stimulation of central thalamus (CT-DBS) has potential for modulating states of consciousness, but it can also trigger spike-wave discharges (SWDs). ObjectivesTo report the probability of inducing SWDs during CT-DBS in awake mice. MethodsMice were implanted with electrodes to deliver unilateral and bilateral CT-DBS at different frequencies while recording EEG. We titrated stimulation current by gradually increasing it at each frequency until an SWD appeared. Subsequent stimulations to test arousal modulation were performed at the current one step below the current that caused an SWD during titration. ResultsIn 2.21% of the test stimulations (10 out of 12 mice), CT-DBS caused SWDs at currents lower than the titrated current, at currents as low as 20 A. ConclusionOur study found a small but significant probability of inducing SWDs even after titration and at relatively low currents. EEG should be closely monitored for SWDs when performing CT-DBS in both research and clinical settings.

neuroscience↗

Robust Working Memory through Short-Term Synaptic Plasticity

Working memory has long been thought to arise from sustained spiking/attractor dynamics. However, recent work has suggested that short-term synaptic plasticity (STSP) may help maintain attractor states over gaps in time with little or no spiking. To determine if STSP endows additional functional advantages, we trained artificial recurrent neural networks (RNNs) with and without STSP to perform an object working memory task. We found that RNNs with and without STSP were able to maintain memories over distractors presented in the middle of the memory delay. However, RNNs with STSP showed activity that was similar to that seen in the cortex of a non-human primate (NHP) performing the same task. By contrast, RNNs without STSP showed activity that was less brain-like. Further, RNNs with STSP were more robust to noise and network degradation than RNNs without STSP. These results show that STSP can not only help maintain working memories, it also makes neural networks more robust and brain-like.

neuroscience↗