Mechanisms of Tactile Information Transmission through Whisker Vibrations

Lottem, Eran; Azouz, Rony

doi:10.1523/jneurosci.0705-09.2009

Cited by 56 publications

(76 citation statements)

References 42 publications

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“…Vibration is an ideal stimulus for two reasons: first, because it can be characterized and precisely controlled in experimental settings by its two elemental parameters, A and f, and second, because it simulates key features of natural stimuli in the environment (23)(24)(25)(26). In earlier studies (22, 23) we applied methods of mutual information to measure the signal carried by barrel cortex neurons about the two elemental features A and f separately and their potential joint encoding.…”

Section: Discussionmentioning

confidence: 99%

Behavioral study of whisker-mediated vibration sensation in rats

Adibi

Diamond

Arabzadeh

2012

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

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Rats use their vibrissal sensory system to collect information about the nearby environment. They can accurately and rapidly identify object location, shape, and surface texture. Which features of whisker motion does the sensory system extract to construct sensations? We addressed this question by training rats to make discriminations between sinusoidal vibrations simultaneously presented to the left and right whiskers. One set of rats learned to reliably identify which of two vibrations had higher frequency (f 1 vs. f 2 ) when amplitudes were equal. Another set of rats learned to reliably identify which of two vibrations had higher amplitude (A 1 vs. A 2 ) when frequencies were equal. Although these results indicate that both elemental features contribute to the rats' sensation, a further test found that the capacity to discriminate A and f was reduced to chance when the difference in one feature was counterbalanced by the difference in the other feature: Rats could not discriminate amplitude or frequency whenever A 1 f 1 = A 2 f 2 . Thus, vibrations were sensed as the product Af rather than as separable elemental features, A and f. The product Af is proportional to a physical entity, the mean speed. Analysis of performance revealed that rats extracted more information about differences in Af than predicted by the sum of the information in elemental differences. These behavioral experiments support the predictions of earlier physiological studies by demonstrating that rats are "blind" to the elemental features present in a sinusoidal whisker vibration; instead, they perceive a composite feature, the speed of whisker motion.barrel cortex | coding R ats use their whiskers to recognize the positions of floors, walls, and objects, particularly in dark surroundings (1-4). Previous studies have characterized the efficacy of whisker-mediated touch in object localization (5, 6), shape recognition (7, 8), gap and aperture width detection (9, 10), texture discrimination (11)(12)(13)(14), and vibration detection/discrimination (15, 16). The accuracy of sensory discriminations, together with the animals' speed in reaching decisions, indicates that the vibrissal sensory system is efficient (17).Several sensorimotor behaviors have been shown to involve the whisker region of the primary somatosensory cortex (17). This region contains anatomically and functionally distinguishable clusters of neurons called "barrels" (18). In rats, each barrel contains an average of 2,500 neurons (19) that respond primarily to their corresponding whisker (20,21). The detailed knowledge of this processing circuitry, combined with the animals' high-level sensory capacities, makes the rat whisker sensory system a good platform for studying the neuronal bases of perception.Because whisker motion is the starting point for most tactile capacities, a critical step is to understand how motion is converted to neuronal firing and how neuronal firing in turn generates sensation. In earlier studies, we analyzed the cortical neuronal activity evoked by sinu...

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Section: Discussionmentioning

confidence: 99%

Behavioral study of whisker-mediated vibration sensation in rats

Adibi

Diamond

Arabzadeh

2012

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

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“…To replay whisker movements associated with texture sensing through head and body movements in anesthetized rats, we placed rotating cylinders covered with textures orthogonal to the whiskers (Lottem and Azouz, 2009). The cylinders were driven by a DC motor (Farnell).…”

Section: Methodsmentioning

confidence: 99%

“…For rodents, arrays of facial whiskers serve as primary tactile organs, which provide the main surface for localization and discrimination of objects in the animal's immediate sensory environment Brecht et al, 1997;Krupa et al, 2002;Szwed et al, 2003;Mehta and Kleinfeld, 2004;Arabzadeh et al, 2005;von Heimendahl et al, 2007;Diamond et al, 2008;Ritt et al, 2008;Wolfe et al, 2008;Lottem and Azouz, 2009). In the whisker somatosensory system, mechanical interactions between each whisker and the environment are sensed by numerous mechanoreceptors located within each follicle-sinus complex (FSC) (Rice et al, 1986;Ebara et al, 2002), which anchors a whisker to the skin.…”

Section: Introductionmentioning

confidence: 99%

“…These studies have yielded abundant insights into mechanoreceptors' structure in the FSC; the studies have also indicated their similarity to mechanoreceptors in other systems and animals. Moreover, they have shown that first-order trigeminal ganglion (TG) neurons can be classified into a variety of functionally distinct subgroups, depending on their threshold sensitivities, their rates of adaptation (Gibson and Welker 1983a,b;Lichtenstein et al, 1990;Shoykhet et al, 2000), and their physiological and behavioral significance (Szwed et al, 2003;Arabzadeh et al, 2005;Lottem and Azouz, 2009). …”

Section: Introductionmentioning

confidence: 99%

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A Unifying Framework Underlying Mechanotransduction in the Somatosensory System

Lottem

Azouz²

2011

Journal of Neuroscience

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Rodents use their whiskers to sense their surroundings. As most of the information available to the somatosensory system originates in whiskers' primary afferents, it is essential to understand the transformation of whisker motion into neuronal activity. Here, we combined in vivo recordings in anesthetized rats with mathematical modeling to ascertain the mechanical and electrical characteristics of mechanotransduction. We found that only two synergistic processes, which reflect the dynamic interactions between (1) receptor and whisker and (2) receptor and surrounding tissue, are needed to describe mechanotransduction during passive whiskers deflection. Interactions between these processes may account for stimulus-dependent changes in the magnitude and temporal pattern of tactile responses on multiple scales. Thus, we are able to explain complex electromechanical processes underlying sensory transduction using a simple model, which captures the responses of a wide range of mechanoreceptor types to diverse sensory stimuli. This compact and precise model allows for a ubiquitous description of how mechanoreceptors encode tactile stimulus.

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“…Their frequency response and other mechanical characteristics have been quantified both in vivo and ex vivo (Hartmann et al, 2003;Neimark et al, 2003), and mechanical response seems to play a key role in signal transduction (Lottem and Azouz, 2009). Each macrovibrissa is mounted in a modified hair follicle, a roughly ellipsoidal capsule around 1mm in diameter and 3mm long (Rice et al, 1986), which is responsible for transducing mechanical signals into neural signals.…”

Section: Morphology Sensory Transduction and Whisker Actuationmentioning

confidence: 99%

Biomimetic robots as scientific models: a view from the whisker tip

Prescott¹,

Mitchinson²,

Pearson³

et al. 2011

Neuromorphic and Brain-Based Robots

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Why build robot models of animals and their nervous systems? One answer is that in building a robot model of a target organism, that mimics sufficiently some aspects of that animal's body, brain and behaviour, we can expect to learn a good deal about the original creature. Synthesis (engineering) is quite different from analysis (reverse-engineering), often easier, and teaches fascinating lessons (Braitenberg, 1986). Another answer is that a robot model should allow us to conduct experiments, that will help us better understand the biological system, and that would be impossible or at least much more difficult to perform in the original animal (Rosenblueth and Wiener, 1945). In this chapter our target organism is the rat and our specific focus is on the sophisticated tactile sensory system provided by that animal's facial whiskers (vibrissae). Neurobiology shows us that the brain nuclei and circuits that process vibrissal touch signals, and that control the positioning and movement of the whiskers, form a neural architecture that is a good model of how the mammalian brain, in general, co-ordinates sensing with action. Thus, by building a robot whisker system, we can take a significant step towards building the first robot 'mammal'. Following a short review of relevant rat biology, this chapter will describe the design and development of two whiskered robot platforms-Whiskerbot and SCRATCHbot-that we have constructed in order to better understand the rat whisker system, and to test hypotheses about whisker control and vibrissal sensing in a physical brain-based device. We provide a description of each platform, including mechanical, electronic and software components, discussing, in relation to each component, the design constraints we sought to meet and the trade-offs made between biomimetic ideals and engineering practicalities. Some results obtained using each platform are described together with a brief outline of future development plans. Finally, we discuss the use of biomimetic robots as scientific models and consider, using the example of whiskered robots, what contribution robotics can make to the brain and behavioural sciences.

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Mechanisms of Tactile Information Transmission through Whisker Vibrations

Cited by 56 publications

References 42 publications

Behavioral study of whisker-mediated vibration sensation in rats

Behavioral study of whisker-mediated vibration sensation in rats

A Unifying Framework Underlying Mechanotransduction in the Somatosensory System

Biomimetic robots as scientific models: a view from the whisker tip

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