Assembly of the dorsal horn somatotopic map

Pb, Brown; Koerber, H. Richard; Millecchia, Ronald

doi:10.1080/08990229771097

Cited by 12 publications

(8 citation statements)

References 60 publications

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“…The primary representation of the body in the dorsal horn of the spinal cord has traditionally been described as a simple map of the skin surface (Molander and Grant, 1985;Brown et al, 1997). However, recent data indicate that this view may not be correct.…”

Section: Introductionmentioning

confidence: 87%

Action-Based Body Maps in the Spinal Cord Emerge from a Transitory Floating Organization

Granmo¹,

Petersson²,

Schouenborg³

2008

J. Neurosci.

101

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During development primary afferents grow into and establish neuronal connections in the spinal cord, thereby forming the basis for how we perceive sensory information and control our movements. In the somatosensory system, myriads of primary afferents, conveying information from different body locations and sensory modalities, get organized in the dorsal horn of the spinal cord so that spinal multisensory circuits receive topographically ordered information. How this intricate pathfinding is brought about during development is, however, largely unknown. Here we show that a body representation closely related to motor patterns emerges from a transitory floating and plastic organization through profound activity-dependent rewiring, involving both sprouting and elimination of afferent connections, and provide evidence for cross-modality interactions in the alignment of the multisensory input. Thus, far from being inborn and stereotypic, the dorsal horn of the spinal cord now appears to be a highly adaptive brain-body interface.

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Section: Introductionmentioning

confidence: 87%

Action-Based Body Maps in the Spinal Cord Emerge from a Transitory Floating Organization

Granmo¹,

Petersson²,

Schouenborg³

2008

J. Neurosci.

101

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“…In cases where the sensory receptors exist in a two-dimensional array, such as the retina or the skin, central organizations can be readily analyzed in terms of a topological mapping that conserves nearest neighbor relationships (e.g., Refs. 43,44). It has been tempting, therefore, to extend this concept to proprioception, even though its receptors may not be so simply arrayed.…”

Section: Topological Projections and Localized Receptive Fieldsmentioning

confidence: 99%

Proprioception From a Spinocerebellar Perspective

Bosco

Poppele

2001

Physiological Reviews

270

176

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This review explores how proprioceptive sensory information is organized at spinal cord levels as it relates to a sense of body position and movement. The topic is considered in an historical context and develops a different framework that may be more in tune with current views of sensorimotor processing in other central nervous system structures. The dorsal spinocerebellar tract (DSCT) system is considered in detail as a model system that may be considered as an end point for the processing of proprioceptive sensory information in the spinal cord. An analysis of this system examines sensory processing at the lowest levels of synaptic connectivity with central neurons in the nervous system. The analysis leads to a framework for proprioception that involves a highly flexible network organization based in some way on whole limb kinematics. The functional organization underlying this framework originates with the biomechanical linkages in the limb that establish functional relationships among the limb segments. Afferent information from limb receptors is processed further through a distributed neural network in the spinal cord. The result is a global representation of hindlimb parameters rather than a muscle-by-muscle or joint-by-joint representation.

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“…The degree of representational overlap, for instance, has been reported as being everything from essentially absent to prominent (Light and Durkovic, 1984;Swett and Woolf, 1985;Woolf and Fitzgerald, 1986;Florence et al, 1988;Maslany et al, 1992;Shortland and Woolf, 1993). Most importantly, however, very few studies have explicitly addressed the functional significance or origin of spinal somatotopy (Koerber et al, 1993;Brown et al, 1997). One possible functional principle could be that spinal somatotopy is the result of developmental and phylogenetic processes adapting sensory input to motor output.…”

mentioning

confidence: 99%

Spinal Sensorimotor Transformation: Relation between Cutaneous Somatotopy and a Reflex Network

et al. 2002

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The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems.

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Assembly of the dorsal horn somatotopic map

Cited by 12 publications

References 60 publications

Action-Based Body Maps in the Spinal Cord Emerge from a Transitory Floating Organization

Action-Based Body Maps in the Spinal Cord Emerge from a Transitory Floating Organization

Proprioception From a Spinocerebellar Perspective

Spinal Sensorimotor Transformation: Relation between Cutaneous Somatotopy and a Reflex Network

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