@article {70, title = {Flutter instability in solids and structures, with a view on biomechanics and metamaterials}, journal = {Proceedings of the Royal Society A}, volume = {479}, year = {2023}, pages = {20230523}, abstract = {

The phenomenon of oscillatory instability called "flutter" was observed in aeroelasticity and rotor dynamics about a century ago. Driven by a series of applications involving non-conservative elasticity theory at different physical scales, ranging from nanomechanics to the mechanics of large space structures and including biomechanical problems of motility and growth, research on flutter is experiencing a new renaissance. A review is presented of the most notable applications and recent advances in fundamentals, both theoretical and experimental aspects, of flutter instability and Hopf bifurcation. Open problems, research gaps and new perspectives for investigations are indicated.

}, keywords = {elasticity, Hopf bifurcation, non-conservative systems, non-Hermitian mechanics, non-holonomic constraints}, doi = {10.1098/rspa.2023.0523}, author = {Davide Bigoni and Francesco Dal Corso and Oleg N. Kirillov and Diego Misseroni and Giovanni Noselli and Andrea Piccolroaz} } @article {53, title = {A fluorescent dye method suitable for visualization of one or more rat whiskers}, journal = {Bio-protocol}, volume = {8}, year = {2018}, chapter = {e2749}, abstract = {

Visualization and tracking of the facial whiskers is critical to many studies of rodent behavior. High-speed videography is the most robust methodology for characterizing whisker kinematics, but whisker visualization is challenging due to the low contrast of the whisker against its background. Recently, we showed that fluorescent dye(s) can be applied to enhance visualization and tracking of whisker(s) (Rigosa et al., 2017), and this protocol provides additional details on the technique.\ 

}, keywords = {barrel cortex, Dye, Fluorescence, Tactile perception, Tracking, Whisker}, doi = {10.21769/BioProtoc.2749}, author = {Jacopo Rigosa and Alessandro Lucantonio and Giovanni Noselli and Arash Fassihi and Fabrizio Manzino and Francesca Pulecchi and Mathew E Diamond} } @article {44, title = {Dye-enhanced visualization of rat whiskers for behavioral studies}, journal = {eLife}, volume = {6:e25290}, year = {2017}, abstract = {

Visualization and tracking of the facial whiskers is required in an increasing number of rodent studies. Though many approaches have been employed, only high-speed videography has proven adequate for measuring whisker motion and deformation during interaction with an object. However, whisker visualization and tracking is challenging for multiple reasons, primary among them the low contrast of the whisker against its background. Here we demonstrate a fluorescent dye method suitable for visualization of one or more rat whiskers. The process makes the dyed whisker(s) easily visible against a dark background. The coloring does not influence the behavioral performance of rats trained on a vibrissal vibrotactile discrimination task, nor does it affect the whiskers{\textquoteright} mechanical properties.

}, keywords = {behavioral studies, dye-enhanced visualization, rat whiskers}, doi = {10.7554/eLife.25290}, author = {Jacopo Rigosa and Alessandro Lucantonio and Giovanni Noselli and Arash Fassihi and Erik Zorzin and Fabrizio Manzino and Francesca Pulecchi and Mathew E Diamond} } @article {34, title = {Unsupervised quantification of whisking and head movement in freely moving rodents}, journal = {Journal of Neurophysiology}, volume = {105}, year = {2011}, pages = {1950-1962}, abstract = {

The rodent whisker system has become the leading experimental paradigm for the study of active sensing. Thanks to more sophisticated behavioral paradigms, progressively better neurophysiological methods, and improved video hardware/software, there is now the prospect of defining the precise connection between the sensory apparatus and brain activity in awake, exploring animals. Achieving this ambitious goal requires quantitative, objective characterization of head and whisker kinematics. This study presents the methodology and potential uses of a new automated motion analysis routine. The program provides full quantification of head orientation and translation, as well as the angle, frequency, amplitude, and bilateral symmetry of whisking. The system operates without any need for manual tracing by the user. Quantitative comparison to whisker detection by expert humans indicates that the program{\textquoteright}s correct detection rate is at \>95\% even on animals with all whiskers intact. Particular attention has been paid to obtaining reliable performance under nonoptimal lighting or video conditions and at frame rates as low as 100. Variation of the zoom across time is compensated for without user intervention. The program adapts automatically to the size and shape of different species. The outcome of our testing indicates that the program can be a valuable tool in quantifying rodent sensorimotor behavior.

}, keywords = {head tracking, snout tracking, whisker tracking}, doi = {10.1152/jn.00764.2010}, author = {Igor Perkon and Andrej Kosir and Pavel M Itskov and Jurij Tasic and Mathew E. Diamond} } @article {33, title = {Whisking and whisker kinematics during a texture classification task}, journal = {Philosophical Transactions of the Royal Society B}, volume = {366}, year = {2011}, pages = {3058-3069}, abstract = {

Rats explore objects by rhythmically whisking with their vibrissae. The goal of the present study is to learn more about the motor output used by rats to acquire texture information as well as the whisker motion evoked by texture contact. We trained four rats to discriminate between different grooved textures and used high-speed video to characterize whisker motion during the task. The variance in whisking parameters among subjects was notable. After whisker trimming, the animals changed their behaviour in ways that appear consistent with an optimization of whisker movement to compensate for lost information. These results lead to the intriguing notion that the rats use an information-seeking {\textquoteleft}cognitive{\textquoteright} motor strategy, instead of a rigid motor programme. Distinct stick/slip events occurred during texture palpation and their frequency increased in relation to the spatial frequency of the grooves. The results allow a preliminary assessment of three candidate texture-coding mechanisms{\textemdash}the number of grooves encountered during each touch, the temporal difference between groove contacts and the spatial pattern of groove contacts across the whiskers.

}, keywords = {stick/slip, texture classification task, touch, vibrissae, whisking}, doi = {10.1098/rstb.2011.0161}, author = {Yanfang Zuo and Igor Perkon and Mathew E. Diamond} }