Multisensory Control of Spinal Reflex Pathways

Lundberg, A.

doi:10.1016/s0079-6123(08)60803-1

Cited by 318 publications

(186 citation statements)

References 41 publications

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“…For several flexion cells, the membrane potential was most hyperpolarized during the ipsilateral hip flexor nerve bursts of fictive scratching and fictive swimming, despite the fact that all flexion cells were activated during the ipsilateral hip flexor nerve burst of fictive flexion reflex. This hip flexor phase hyperpolarization during scratching and swimming emphasizes that these cells are specialized for the limb withdrawal behavior, or the sen- sory stimulus that evokes this behavior, rather than contributing generally to the hip flexor phase of a wide variety of behaviors (Jankowska et al, 1967;Lundberg, 1979;Ostry et al, 1991;Sandrini et al, 2005). Finally, there is evidence from kinematic and motor pattern analyses that limb withdrawal involves separate spinal circuitry from that used in the flexion phases of turtle scratching and frog wiping (Stein et al, 1982;Schotland and Rymer, 1993a,b).…”

Section: Flexion Cells Are Rhythmically Hyperpolarized During Fictivementioning

confidence: 99%

“…Sherrington recognized similarities between flexion reflex and the flexion phases of scratching and stepping but noted that flexion reflex can interrupt scratching or stepping, and vice versa; he thus suggested that flexion reflex stimuli compete with scratch and step stimuli to control muscles (Sherrington, 1906(Sherrington, , 1910. It was later suggested, however, that a common "flexor reflex afferents" network contributes to limb withdrawal, locomotion, and scratching (Jankowska et al, 1967;Lundberg, 1979). Moreover, flexion reflex can reset an ongoing scratch or locomotor rhythm, indicating that some flexion reflex circuitry may be shared with rhythmgenerating circuitry (Currie and Stein, 1989;Schomburg et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

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Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Berkowitz¹

2007

J. Neurosci.

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Behavioral choices in invertebrates are mediated by a combination of shared and specialized circuitry, including neurons that are inhibited during competing behaviors. Less is known, however, about the neural mechanisms of behavioral choice in vertebrates. The spinal cord can appropriately select among several types of limb movements, including limb withdrawal (flexion reflex), scratching, and locomotion, and thus is conducive to examination of vertebrate mechanisms of behavioral choice. Flexion reflex can interrupt and reset the rhythm of scratching and locomotion, suggesting that a combination of shared and specialized circuitry contributes to these behaviors, but little is known about the interneurons involved. Here, I used in vivo intracellular recording and dye injection to identify a group of spinal interneurons that are strongly activated during fictive flexion reflex but inhibited during fictive scratching and fictive swimming. These flexion-selective interneurons are typically rhythmically hyperpolarized during fictive scratching and fictive swimming. This hyperpolarization can be maximal during the ipsilateral hip flexor bursts of rhythmic limb motor patterns, although these cells are strongly activated during the ipsilateral hip flexor bursts of fictive flexion reflex. Thus, these interneurons are relatively specialized for fictive limb withdrawal, rather than contributing to the hip flexor phase of multiple types of limb movements. These flexion-selective cells are physiologically and morphologically distinguishable from a recently described group of spinal interneurons (transverse interneurons) that are strongly activated during both fictive flexion reflex and fictive scratching. Thus, spinal interneurons with distinct behavioral roles may to some extent be morphologically distinguishable.

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Section: Flexion Cells Are Rhythmically Hyperpolarized During Fictivementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Berkowitz¹

2007

J. Neurosci.

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“…3 The latter observation indicates a suppression of interneuronal (IN) activity mediating this polysynaptic re¯ex (for review see 9 ).…”

Section: From Spinal Shock To Spasticitymentioning

confidence: 99%

“…The pathway underlying thē exor re¯ex is a polysynaptic spinal one and allows the integration of inputs from muscles, joints and cutaneous a erents on common interneurons. 9 The changes in¯exor re¯ex excitability may at least partly be re¯ected in the appearance of muscle spasms. The increase in muscle tone may be due to a more general recovery of spinal neuronal (alpha-MN and IN) activity.…”

Section: From Spinal Shock To Spasticitymentioning

confidence: 99%

Spastic movement disorder

Dietz¹

2000

Spinal Cord

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This review deals with the neuronal mechanisms underlying spastic movement disorder, assessed by electrophysiological means with the aim of ®rst, a better understanding of the underlying pathophysiology and second, the selection of an adequate treatment. For the patient usually one of the ®rst symptoms of a lesion within the central motor system represents the movement disorder, which is most characteristic during locomotion in patients with spasticity. The clinical examination reveals exaggerated tendon tap re¯exes and increased muscle tone typical of the spastic movement disorder. However, today we know that there exists only a weak relationship between the physical signs obtained during the clinical examination in a passive motor condition and the impaired neuronal mechanisms being in operation during an active movement. By the recording and analysis of electrophysiological and biomechanical parameters during a functional movement such as locomotion, the signi®cance of, for example, impaired re¯ex behaviour or pathophysiology of muscle tone and its contribution to the movement disorder can reliably be assessed. Consequently, an adequate treatment should not be restricted to the cosmetic therapy and correction of an isolated clinical parameter but should be based on the pathophysiology and signi®cance of the mechanisms underlying the disorder of functional movement which impairs the patient. Spinal Cord (2000) 38, 389 ± 393

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“…This centre has the putative function of processing information prior to Sherrington's 'final common path'. The second indicated that certain segmental reflex activity was only present in the presence of brain bulbospinal influence (Lundberg, 1979).…”

mentioning

confidence: 99%

Neurophysiology in spinal cord injury

Dimitrijevič

1987

Spinal Cord

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Multisensory Control of Spinal Reflex Pathways

Cited by 318 publications

References 41 publications

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Spinal Interneurons That Are Selectively Activated during Fictive Flexion Reflex

Spastic movement disorder

Neurophysiology in spinal cord injury

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