Organization of the spinal trigeminal nucleus in star‐nosed moles

Sawyer, Eva K.; Leitch, Duncan B.; Catania, Kenneth C.

doi:10.1002/cne.23605

Cited by 19 publications

(17 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lima-bean shape probably comes from devoting a similarsized volume of tissue to the representation of both the upper and the lower jaws, instead of the nucleus being dominated by the representation of the upper jaw. The inverted representation is consistent with that found in other animals, including rodents (25,26), cats (27), moles (28), and pigeons (29).…”

Section: Discussionsupporting

confidence: 88%

Subcortical barrelette-like and barreloid-like structures in the prosimian galago ( Otolemur garnetti )

Sawyer

Liao

et al. 2015

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

View full text Add to dashboard Cite

Galagos are prosimian primates that resemble ancestral primates more than most other extant primates. As in many other mammals, the facial vibrissae of galagos are distributed across the upper and lower jaws and above the eye. In rats and mice, the mystacial macrovibrissae are represented throughout the ascending trigeminal pathways as arrays of cytoarchitecturally distinct modules, with each module having a nearly one-to-one relationship with a specific facial whisker. The macrovibrissal representations are termed barrelettes in the trigeminal somatosensory brainstem, barreloids in the ventroposterior medial subnucleus of the thalamus, and barrels in primary somatosensory cortex. Despite the presence of facial whiskers in all nonhuman primates, barrel-like structures have not been reported in primates. By staining for cytochrome oxidase, Nissl, and vesicular glutamate transporter proteins, we show a distinct array of barrelette-like and barreloid-like modules in the principal sensory nucleus, the spinal trigeminal nucleus, and the ventroposterior medial subnucleus of the galago, Otolemur garnetti. Labeled terminals of primary sensory neurons in the brainstem and cell bodies of thalamocortically projecting neurons demonstrate that barrelette-like and barreloid-like modules are located in areas of these somatosensory nuclei that are topographically consistent with their role in facial touch. Serendipitously, the plane of section that best displays the barreloid-like modules reveals a remarkably distinct homunculus-like patterning which, we believe, is one of the clearest somatotopic maps of an entire body surface yet found.vibrissa | barrel cortex | trigeminal | somatosensory maps | primate N early all mammals use facial vibrissae as a sensory organ to transduce distant touch. In some species, but most famously in rats and mice, individual whiskers have been shown to be represented as distinct modules in the ascending lemniscal and paralemniscal somatosensory pathways (1). These modules have been termed barrelettes, barreloids, and barrels in the brainstem, thalamus, and cortex, respectively (2-5). The discovery of the barrel pathway has allowed researchers to visualize how somatosensory inputs are anatomically organized in the brain. The barrel pattern provides clear anatomical landmarks that enable further research on the development, connection, functional organization, and plasticity of the somatosensory system. Many investigators have embraced this system in their research programs (for review, see refs. 6 and 7). Beyond the experimental convenience of the system, the nearly perfect correspondence of one whisker to one barrel invokes questions about the development and evolution of nervous systems in general, such as whether development of the organization of sensory systems is largely controlled by properties intrinsic to the central nervous system or largely dictated by the arrangement of peripheral receptors (8, 9). In addition, do whisker modules have a function, or are they just a spandrel (10, 11) that...

show abstract

Section: Discussionsupporting

confidence: 88%

Subcortical barrelette-like and barreloid-like structures in the prosimian galago ( Otolemur garnetti )

Sawyer

Liao

et al. 2015

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

View full text Add to dashboard Cite

show abstract

“…Each Eimer's organ is innervated by myelinated trigeminal LTMRs terminating in Merkel cell-neurite complexes, in Pacinian-like corpuscles, or as free nerve endings (FIGURE 1), with an average of 6,110 fibers/ray, which together constitute the densest population of mechanoreceptive end-organs found in mammals (9,68). This diversity of mechanoreceptors enables the Eimer's organ to recognize both static and dynamic stimuli with high precision and accuracy (52).…”

Section: Star-nosed Mole (Condylura Cristata)mentioning

confidence: 97%

Evolutionary Specialization of Tactile Perception in Vertebrates

2016

View full text Add to dashboard Cite

Evolution has endowed vertebrates with the remarkable tactile ability to explore the world through the perception of physical force. Yet the sense of touch remains one of the least well understood senses at the cellular and molecular level. Vertebrates specializing in tactile perception can highlight general principles of mechanotransduction. Here, we review cellular and molecular adaptations that underlie the sense of touch in typical and acutely mechanosensitive vertebrates.

show abstract

“…A nimals with acute sense of touch provide an opportunity to study cellular and molecular principles of mechanoreception from an unconventional perspective (1,2). Tactile-foraging waterfowl of the Anatidae family rely on their acute sense of touch rather than vision to find food.…”

mentioning

confidence: 99%

Neuronal mechanism for acute mechanosensitivity in tactile-foraging waterfowl

Schneider

Mastrotto

Laursen

et al. 2014

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

View full text Add to dashboard Cite

Relying almost exclusively on their acute sense of touch, tactileforaging birds can feed in murky water, but the cellular mechanism is unknown. Mechanical stimuli activate specialized cutaneous end organs in the bill, innervated by trigeminal afferents. We report that trigeminal ganglia (TG) of domestic and wild tactileforaging ducks exhibit numerical expansion of large-diameter mechanoreceptive neurons expressing the mechano-gated ion channel Piezo2. These features are not found in visually foraging birds. Moreover, in the duck, the expansion of mechanoreceptors occurs at the expense of thermosensors. Direct mechanical stimulation of duck TG neurons evokes high-amplitude depolarizing current with a low threshold of activation, high signal amplification gain, and slow kinetics of inactivation. Together, these factors contribute to efficient conversion of light mechanical stimuli into neuronal excitation. Our results reveal an evolutionary strategy to hone tactile perception in vertebrates at the level of primary afferents.A nimals with acute sense of touch provide an opportunity to study cellular and molecular principles of mechanoreception from an unconventional perspective (1, 2). Tactile-foraging waterfowl of the Anatidae family rely on their acute sense of touch rather than vision to find food. Using a complex array of highly coordinated feeding techniques-straining, pecking, and dabbling-they can selectively collect gastropods, worms, crustaceans, and plant matter even in murky water with high precision and efficiency. This highly discriminatory feeding behavior relies on the acquisition and rapid processing of sensory information coming from numerous mechanoreceptors in the bill (3).Mechanoreceptors are cell-neurite complexes that specialize in the detection of diverse mechanical stimuli. The most numerous mechanoreceptors in the bill skin of Anatidae birds are Herbst and Grandry corpuscles, which are present at high density (up to 150 receptors per square millimeter) 50-100 μm below the epidermis of dorsal and ventral surfaces of the upper and lower bill (4, 5). The mechanoreceptors are innervated by rapidly adapting primary afferents projecting from the trigeminal ganglia (TG) (Fig. 1A) and are best tuned to detect vibration and velocity (6-10). In this sense, Herbst and Grandry organs appear functionally homologous to the mammalian Pacinian and Meissner corpuscles, respectively. Following stimulus detection, mechanosensory information is processed in the trigeminal nucleus (PrV) of the brainstem. In tactile foragers, such as ducks, PrV accounts for a significantly larger fraction of total brain volume compared with visual foragers, such as chicken (11). This augmented neural representation reflects the need to process the complex and abundant tactile information from the primary afferents of the trigeminal nerve. However, even though the general layout of the mechanosensory system is well established, the contribution of primary afferents in stimulus detection is unclear.In rodents, over 80% of somatose...

show abstract

Organization of the spinal trigeminal nucleus in star‐nosed moles

Cited by 19 publications

References 59 publications

Subcortical barrelette-like and barreloid-like structures in the prosimian galago ( Otolemur garnetti )

Subcortical barrelette-like and barreloid-like structures in the prosimian galago ( Otolemur garnetti )

Evolutionary Specialization of Tactile Perception in Vertebrates

Neuronal mechanism for acute mechanosensitivity in tactile-foraging waterfowl

Contact Info

Product

Resources

About