From innervation density to tactile acuity

Brown, Paul B.; Koerber, H. Richard; Millecchia, Ronald

doi:10.1016/j.brainres.2004.03.009

Cited by 42 publications

(31 citation statements)

References 50 publications

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“…Nevertheless, mirror-image termination patterns for corresponding skin sites were found in the right and left spinal hemicords in individual neonates, indicating that, for given conditions, the ingrowth of the primary afferents is to a large extent determined by genetic programs. Assuming that competition for space and trophic support are factors of critical importance for the establishment and preservation of synaptic connections (Fitzgerald, 2005), it is conceivable that the initial variation between animals is attributable to factors such as innervation density (Brown et al, 2004), dorsal root ganglion cell death (Oppenheim, 1991), reorganization of dorsal root ganglion cells (Knaut et al, 2005), and relative timing of primary afferent ingrowth from different skin areas (Jackman and Fitzgerald, 2000). Our data, in particular, indicate an important role for central plastic mechanisms, and although minor changes in peripheral projections could also contribute to the floating body representation in young animals, previous studies have shown that the nerves innervating the skin areas studied are in place already at birth (Mirnics and Koerber, 1995a;Jackman and Fitzgerald, 2000).…”

Section: Discussionmentioning

confidence: 99%

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: Discussionmentioning

confidence: 99%

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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“…Lateral inhibition consists of a local network of inhibitory interneurons that connect adjacent cortical neurons. Firing of one cortical neuron tends to lead to inhibition of its neighbours (Brown et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Congruency of body-related information induces somatosensory reorganization

Cardini

Longo

2016

Neuropsychologia

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Chronic pain and impaired tactile sensitivity are frequently associated with "blurred" representations in the somatosensory cortex. The factors that produce such somatosensory blurring, however, remain poorly understood. We manipulated visuotactile congruence to investigate its role in promoting somatosensory reorganization.To this aim we used the mirror box illusion that produced in participants the subjective feeling of looking directly at their left hand, though they were seeing the reflection of their right hand. Simultaneous touches were applied to the middle or ring finger of each hand. In one session, the same fingers were touched (for example both middle fingers), producing a congruent percept; in the other session different fingers were touched, producing an incongruent percept. In the somatosensory system, 3

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“…The overlap or “coverage factor” of the “tiling” that occurs in the ganglion cell mosaics of the retina, for example, has been explored by Balasubramanian and Sterling (2009), and these investigators have demonstrated mathematically that sensory sensitivity and acuity are maximized by overlapping receptive fields. Similarly, Brown and colleagues (2004) have calculated that the same receptive field principles operate in the case of cutaneous mechanoreceptive fields. If such conclusions can be extrapolated from first-order retinal ganglion cells and cutaneous mechanoreceptors to first-order nodose afferents, then the IMAs forming the high-density mechanoreceptor ring in the pylorus should generate a high resolution and sensitive representation of the mechanical dynamics that play in the pyloric canal.…”

Section: Discussionmentioning

confidence: 95%

Organization of vagal afferents in pylorus: Mechanoreceptors arrayed for high sensitivity and fine spatial resolution?

Powley¹,

Hudson²,

McAdams³

et al. 2014

Autonomic Neuroscience

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The pylorus is innervated by vagal mechanoreceptors that project to gastrointestinal smooth muscle, but the distributions and specializations of vagal endings in the sphincter have not been fully characterized. To evaluate their organization, the neural tracer dextran biotin was injected into the nodose ganglia of rats. Following tracer transport, animals were perfused, and their pylori and antra were prepared as whole mounts. Specimens were processed to permanently label the tracer, and subsets were counterstained with Cuprolinic blue or immunostained for c-Kit. Intramuscular arrays (IMAs) in the circular muscle comprised the principal vagal afferent innervation of the sphincter. These pyloric ring IMAs were densely distributed and evidenced a variety of structural specializations. Morphometric comparisons between the arbors innervating the pylorus and a corresponding sample of IMAs in the adjacent antral circular muscle highlighted that sphincter IMAs branched profusely, forming more than twice as many branches as did antral IMAs (means of 405 vs. 165, respectively), and condensed their numerous neurites into compact receptive fields (~48% of the area of antral IMAs) deep in the circular muscle (~6 μm above the submucosa). Separate arbors of IMAs in the sphincter interdigitated and overlapped to form a 360° band of mechanoreceptors encircling the pyloric canal. The annulus of vagal IMA arbors, putative stretch receptors tightly intercalated in the sphincter ring and situated near the lumen of the pyloric canal, creates an architecture with the potential to generate gut reflexes on the basis of pyloric sensory maps of high sensitivity and fine spatial resolution.

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From innervation density to tactile acuity

Cited by 42 publications

References 50 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

Congruency of body-related information induces somatosensory reorganization

Organization of vagal afferents in pylorus: Mechanoreceptors arrayed for high sensitivity and fine spatial resolution?

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