Quantification of vibrissal mechanical properties across the rat mystacial pad

Yang, Anne; Belli, Hayley M.; Hartmann, Mitra J. Z.

doi:10.1152/jn.00869.2016

Cited by 9 publications

(14 citation statements)

References 59 publications

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“…Although high speed 3D imaging in animals freely whisking at natural objects would be needed to better answer this question (Hobbs et al, 2015), the complex 3D structure of natural surfaces could lead to moments when select sets of non-adjacent whiskers could come into contact with objects. Additionally, whiskers are of variable length and physical properties (Yang et al, 2019) which could also lead to non-intuitive spatio-temporal sequences of whisker-object contacts.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of a comprehensive population code for contextual features in the awake sensory cortex

Lyall

Mossing

Pluta³

et al. 2021

eLife

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How cortical circuits build representations of complex objects is poorly understood. Individual neurons must integrate broadly over space, yet simultaneously obtain sharp tuning to specific global stimulus features. Groups of neurons identifying different global features must then assemble into a population that forms a comprehensive code for these global stimulus properties. Although the logic for how single neurons summate over their spatial inputs has been well explored in anesthetized animals, how large groups of neurons compose a flexible population code of higher-order features in awake animals is not known. To address this question, we probed the integration and population coding of higher-order stimuli in the somatosensory and visual cortices of awake mice using two-photon calcium imaging across cortical layers. We developed a novel tactile stimulator that allowed the precise measurement of spatial summation even in actively whisking mice. Using this system, we found a sparse but comprehensive population code for higher-order tactile features that depends on a heterogeneous and neuron-specific logic of spatial summation beyond the receptive field. Different somatosensory cortical neurons summed specific combinations of sensory inputs supra-linearly, but integrated other inputs sub-linearly, leading to selective responses to higher-order features. Visual cortical populations employed a nearly identical scheme to generate a comprehensive population code for contextual stimuli. These results suggest that a heterogeneous logic of input-specific supra-linear summation may represent a widespread cortical mechanism for the synthesis of sparse higher-order feature codes in neural populations. This may explain how the brain exploits the thalamocortical expansion of dimensionality to encode arbitrary complex features of sensory stimuli.

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Section: Discussionmentioning

confidence: 99%

Synthesis of a comprehensive population code for contextual features in the awake sensory cortex

Lyall

Mossing

Pluta³

et al. 2021

eLife

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“…It allows for the investigation of the facial skin and whisker pad completely deprived of afferent input. The whisker pad represents a sensory apparatus of huge interest in the fields of behavioral studies, cognitive plasticity and biomechanics (Guntinas-Lichius et al, 2002 ; Tomov et al, 2002 ; Seitz et al, 2011 ; Mameli et al, 2017 ; Yang et al, 2019 ). Furthermore, our denervation model prevents any aberrant reinnervation of the whisker pad from other afferent branches of the trigeminal nerve.…”

Section: Discussionmentioning

confidence: 99%

Selective Denervation of the Facial Dermato-Muscular Complex in the Rat: Experimental Model and Anatomical Basis

et al. 2021

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The facial dermato-muscular system consists of highly specialized muscles tightly adhering to the overlaying skin and thus form a complex morphological conglomerate. This is the anatomical and functional basis for versatile facial expressions, which are essential for human social interaction. The neural innervation of the facial skin and muscles occurs via branches of the trigeminal and facial nerves. These are also the most commonly pathologically affected cranial nerves, often requiring surgical treatment. Hence, experimental models for researching these nerves and their pathologies are highly relevant to study pathophysiology and nerve regeneration. Experimental models for the distinctive investigation of the complex afferent and efferent interplay within facial structures are scarce. In this study, we established a robust surgical model for distinctive exploration of facial structures after complete elimination of afferent or efferent innervation in the rat. Animals were allocated into two groups according to the surgical procedure. In the first group, the facial nerve and in the second all distal cutaneous branches of the trigeminal nerve were transected unilaterally. All animals survived and no higher burden was caused by the procedures. Whisker pad movements were documented with video recordings 4 weeks after surgery and showed successful denervation. Whole-mount immunofluorescent staining of facial muscles was performed to visualize the innervation pattern of the neuromuscular junctions. Comprehensive quantitative analysis revealed large differences in afferent axon counts in the cutaneous branches of the trigeminal nerve. Axon number was the highest in the infraorbital nerve (28,625 ± 2,519), followed by the supraorbital nerve (2,131 ± 413), the mental nerve (3,062 ± 341), and the cutaneous branch of the mylohyoid nerve (343 ± 78). Overall, this surgical model is robust and reliable for distinctive surgical deafferentation or deefferentation of the face. It may be used for investigating cortical plasticity, the neurobiological mechanisms behind various clinically relevant conditions like facial paralysis or trigeminal neuralgia as well as local anesthesia in the face and oral cavity.

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“…The relationship between kinematics and dynamics is primarily determined by material properties (density, Young's modulus, damping) of the whisker and is therefore dependent on the model assumptions for these parameter values. Previous work has found that density as well as Young's modulus vary between proximal and distal whisker regions (22,38,39). In WHISKiT Physics, parameters were chosen to be within the range of biological variation: density was approximated to increase linearly from base to tip, while Young's modulus and damping properties were assumed to be homogeneous within and across whiskers.…”

Section: Discussionmentioning

confidence: 99%

A dynamical model for generating synthetic data to quantify active tactile sensing behavior in the rat

Zweifel

Bush

Abraham

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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As it becomes possible to simulate increasingly complex neural networks, it becomes correspondingly important to model the sensory information that animals actively acquire: the biomechanics of sensory acquisition directly determines the sensory input and therefore neural processing. Here, we exploit the tractable mechanics of the well-studied rodent vibrissal (“whisker”) system to present a model that can simulate the signals acquired by a full sensor array actively sampling the environment. Rodents actively “whisk” ∼60 vibrissae (whiskers) to obtain tactile information, and this system is therefore ideal to study closed-loop sensorimotor processing. The simulation framework presented here, WHISKiT Physics, incorporates realistic morphology of the rat whisker array to predict the time-varying mechanical signals generated at each whisker base during sensory acquisition. Single-whisker dynamics were optimized based on experimental data and then validated against free tip oscillations and dynamic responses to collisions. The model is then extrapolated to include all whiskers in the array, incorporating each whisker’s individual geometry. Simulation examples in laboratory and natural environments demonstrate that WHISKiT Physics can predict input signals during various behaviors, currently impossible in the biological animal. In one exemplary use of the model, the results suggest that active whisking increases in-plane whisker bending compared to passive stimulation and that principal component analysis can reveal the relative contributions of whisker identity and mechanics at each whisker base to the vibrissotactile response. These results highlight how interactions between array morphology and individual whisker geometry and dynamics shape the signals that the brain must process.

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Quantification of vibrissal mechanical properties across the rat mystacial pad

Cited by 9 publications

References 59 publications

Synthesis of a comprehensive population code for contextual features in the awake sensory cortex

Synthesis of a comprehensive population code for contextual features in the awake sensory cortex

Selective Denervation of the Facial Dermato-Muscular Complex in the Rat: Experimental Model and Anatomical Basis

A dynamical model for generating synthetic data to quantify active tactile sensing behavior in the rat

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