Transient shape morphing of active gel plates: geometry and physics.

The control of shape in active structures is a key problem for the realization of smart sensors and actuators, which often draw inspiration from natural systems. In this context, slender structures, such as thin plates, have been studied as a relevant example of shape morphing systems where curvature is generated by in-plane incompatibilities. In particular, in hydrogel plates these incompatibilities can be programmed at fabrication time, such that a target configuration is attained at equilibrium upon swelling or shrinking.

A Fluorescent Dye Method Suitable for Visualization of One or More Rat Whiskers.

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 , 2017 ), and this protocol provides additional details on the technique.

Dye-enhanced visualization of rat whiskers for behavioral studies.

Visualization and tracking of the facial whiskers is required in an increasing number of rodent studies. Although 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.

Neuronal encoding of natural stimuli: the rat tactile system.

A major challenge of sensory systems neuroscience is to quantify the brain activity underlying perceptual experiences and to explain this activity as the outcome of elemental neuronal response properties. One strategy is to measure variations in neuronal response in relation to controlled variations in an artificial stimulus. The limitation is that the stimuli scarcely resemble those which the sensory system has evolved to process-natural, behaviourally relevant stimuli.

Texture signals in whisker vibrations.

Rodents excel in making texture judgments by sweeping their whiskers across a surface. Here we aimed to identify the signals present in whisker vibrations that give rise to such fine sensory discriminations. First, we used sensors to capture vibration signals in metal whiskers during active whisking of an artificial system and in natural whiskers during whisking of rats in vivo.

Neuronal encoding of texture in the whisker sensory pathway.

A major challenge of sensory systems neuroscience is to quantify brain activity underlying perceptual experiences and to explain this activity as the outcome of elemental neuronal response properties. Rats make extremely fine discriminations of texture by "whisking" their vibrissae across an object's surface, yet the neuronal coding underlying texture sensations remains unknown. Measuring whisker vibrations during active whisking across surfaces, we found that each texture results in a unique "kinetic signature" defined by the temporal profile of whisker velocity.