Spinal premotor interneurons controlling antagonistic muscles are spatially intermingled.

Elaborate behaviours are produced by tightly controlled flexor-extensor motor neuron activation patterns. Motor neurons are regulated by a network of interneurons within the spinal cord, but the computational processes involved in motor control are not fully understood. The neuroanatomical arrangement of motor and premotor neurons into topographic patterns related to their controlled muscles is thought to facilitate how information is processed by spinal circuits.

Neurotransmitters and Motoneuron Contacts of Multifunctional and Behaviorally Specialized Turtle Spinal Cord Interneurons.

The spinal cord can appropriately generate diverse movements, even without brain input and movement-related sensory feedback, using a combination of multifunctional and behaviorally specialized interneurons. The adult turtle spinal cord can generate motor patterns underlying forward swimming, three forms of scratching, and limb withdrawal (flexion reflex). We previously described turtle spinal interneurons activated during both scratching and swimming (multifunctional interneurons), interneurons activated during scratching but not swimming (scratch-specialized interneurons), and interneurons activated during flexion reflex but not scratching or swimming (flexion reflex-selective interneurons).

The mammalian spinal commissural system: properties and functions.

Commissural systems are essential components of motor circuits that coordinate left-right activity of the skeletomuscular system. Commissural systems are found at many levels of the neuraxis including the cortex, brainstem, and spinal cord. In this review we will discuss aspects of the mammalian spinal commissural system.

Correction: Is Remodelling of Corticospinal Tract Terminations Originating in the Intact Hemisphere Associated with Recovery following Transient Ischaemic Stroke in the Rat?

[This corrects the article DOI: 10.1371/journal.pone.

Correction: Corticospinal and Reticulospinal Contacts on Cervical Commissural and Long Descending Propriospinal Neurons in the Adult Rat Spinal Cord; Evidence for Powerful Reticulospinal Connections.

[This corrects the article DOI: 10.1371/journal.pone.

Is Remodelling of Corticospinal Tract Terminations Originating in the Intact Hemisphere Associated with Recovery following Transient Ischaemic Stroke in the Rat?

Following large strokes that encompass the cerebral cortex, it has been suggested that the corticospinal tract originating from the non-ischaemic hemisphere reorganises its pattern of terminal arborisation within the spinal cord to compensate for loss of function. However many strokes in humans predominantly affect subcortical structures with minimal involvement of the cerebral cortex. The aim of the present study was to determine whether remodelling of corticospinal terminals arising from the non-ischaemic hemisphere was associated with spontaneous recovery in rats with subcortical infarcts.

Corticospinal and Reticulospinal Contacts on Cervical Commissural and Long Descending Propriospinal Neurons in the Adult Rat Spinal Cord; Evidence for Powerful Reticulospinal Connections.

Descending systems have a crucial role in the selection of motor output patterns by influencing the activity of interneuronal networks in the spinal cord. Commissural interneurons that project to the contralateral grey matter are key components of such networks as they coordinate left-right motor activity of fore and hind-limbs. The aim of this study was to determine if corticospinal (CST) and reticulospinal (RST) neurons make significant numbers of axonal contacts with cervical commissural interneurons.

The spino-bulbar-cerebellar pathway: Activation of neurons projecting to the lateral reticular nucleus in the rat in response to noxious mechanical stimuli.

It is now well established that the cerebellum receives input from nociceptors which may serve to adjust motor programmes in response to pain and injury. In this study, we investigated the possibility that spinoreticular neurons (SRT) which project to a pre-cerebellar nucleus, the lateral reticular nucleus (LRt), respond to noxious mechanical stimulation. Seven adult male rats received stereotaxic injections of the b subunit of cholera toxin in the LRt.

The spino-bulbar-cerebellar pathway: organization and neurochemical properties of spinal cells that project to the lateral reticular nucleus in the rat.

In addition to classical spinocerebellar pathways, the cerebellum receives information from the spinal cord indirectly via spino-bulbar-cerebellar systems. One of the structures in this pathway is the lateral reticular nucleus (LRt). We performed series of experiments to investigate the organization and neurotransmitter content of spinoreticular tract (SRT) neurons in the lumbar spinal cord that project to the LRt.

The recurrent case for the Renshaw cell.

Although Renshaw cells (RCs) were discovered over half a century ago, their precise role in recurrent inhibition and ability to modulate motoneuron excitability have yet to be established. Indirect measurements of recurrent inhibition have suggested only a weak modulatory effect but are limited by the lack of observed motoneuron responses to inputs from single RCs. Here we present dual recordings between connected RC-motoneuron pairs, performed on mouse spinal cord.

Origin and neurochemical properties of bulbospinal neurons projecting to the rat lumbar spinal cord via the medial longitudinal fasciculus and caudal ventrolateral medulla.

Bulbospinal systems (BS) originate from various regions of the brainstem and influence spinal neurons by classical synaptic and modulatory mechanisms. Our aim was to determine the brainstem locations of cells of origin of BS pathways passing through the medial longitudinal fasciculus (MLF) and the caudal ventrolateral medulla (CVLM). We also examined the transmitter content of spinal terminations of the CVLM pathway.

Excitatory inputs to four types of spinocerebellar tract neurons in the cat and the rat thoraco-lumbar spinal cord.

The cerebellum receives information from the hindlimbs through several populations of spinocerebellar tract neurons. Although the role of these neurons has been established in electrophysiological experiments, the relative contribution of afferent fibres and central neurons to their excitatory input has only been estimated approximately so far. Taking advantage of differences in the immunohistochemistry of glutamatergic terminals of peripheral afferents and of central neurons (with vesicular glutamate transporters VGLUT1 or VGLUT2, respectively), we compared sources of excitatory input to four populations of spinocerebellar neurons in the thoraco-lumbar spinal cord: dorsal spinocerebellar tract neurons located in Clarke's column (ccDSCT) and in the dorsal horn (dhDSCT) and ventral spinocerebellar tract (VSCT) neurons including spinal border (SB) neurons.

Implementation and evaluation of a multisite drug usage evaluation program across Australian hospitals - a quality improvement initiative.

Background: With the use of medicines being a broad and extensive part of health management, mechanisms to ensure quality use of medicines are essential. Drug usage evaluation (DUE) is an evidence-based quality improvement methodology, designed to improve the quality, safety and cost-effectiveness of drug use. The purpose of this paper is to describe a national DUE methodology used to improve health care delivery across the continuum through multi-faceted intervention involving audit and feedback, academic detailing and system change, and a qualitative assessment of the methodology, as illustrated by the Acute Postoperative Pain Management (APOP) project.

Properties of axon terminals contacting intermediate zone excitatory and inhibitory premotor interneurons with monosynaptic input from group I and II muscle afferents.

The intermediate zone of the spinal grey matter contains premotor interneurons mediating reflex actions of group I and II muscle afferents. However, limited information is available on how activity of inhibitory versus excitatory interneurons in this population are modulated and how they contribute to motor networks. There were three aims of this study: (1) to characterize excitatory axonal contacts on interneurons; (2) to determine if contact patterns on excitatory and inhibitory interneurons are different; (3) to determine if there are differences in presynaptic inhibitory control of excitatory and inhibitory interneurons.

A population of large neurons in laminae III and IV of the rat spinal cord that have long dorsal dendrites and lack the neurokinin 1 receptor.

The dorsal horn of the rat spinal cord contains a population of large neurons with cell bodies in laminae III or IV, that express the neurokinin 1 receptor (NK1r) and have long dorsal dendrites that branch extensively within the superficial laminae. In this study, we have identified a separate population of neurons that have similar dendritic morphology, but lack the NK1r. These cells also differ from the NK1r-expressing neurons in that they have significantly fewer contacts from substance P-containing axons and are not retrogradely labelled following injection of tracer into the caudal ventrolateral medulla.

Morphology of inhibitory and excitatory interneurons in superficial laminae of the rat dorsal horn.

If we are to stand any chance of understanding the circuitry of the superficial dorsal horn, it is imperative that we can identify which classes of interneuron are excitatory and which are inhibitory. Our aim was to test the hypothesis that there is a correlation between the morphology of an interneuron and its postsynaptic action. We used in vitro slice preparations of the rat spinal cord to characterize and label interneurons in laminae I-III with Neurobiotin.

A new approach to reconstruction models of dendritic branching patterns.

Quantitative models for characterising the detailed branching patterns of dendritic trees aim to explain these patterns either in terms of growth models based on principles of dendritic development or reconstruction models that describe an existing structure by means of a canonical set of elementary properties of dendritic morphology, which when incorporated into an algorithmic procedure will generate samples of dendrites that are statistically indistinguishable in both canonical and emergent features from those of the original sample of real neurons. This article introduces a conceptually new approach to reconstruction modelling based on the single assumption that dendritic segments are built from sequences of units of constant diameter, and that the distribution of the lengths of units of similar diameter is independent of location within a dendritic tree. This assumption in combination with non-parametric methods for estimating univariate and multivariate probability densities leads to an algorithm that significantly reduces the number of basic parameters required to simulate dendritic morphology.

Differential projections of excitatory and inhibitory dorsal horn interneurons relaying information from group II muscle afferents in the cat spinal cord.

Dorsal horn interneurons with input from group II muscle spindle afferents are components of networks involved in motor control. Thirteen dorsal horn interneurons with monosynaptic group II input were characterized electrophysiologically and labeled intracellularly with Neurobiotin. Their axonal projections were traced, and neurotransmitter content was established by using immunocytochemistry.

Empiric management of community-acquired pneumonia in Australian emergency departments.

Objective: To describe empiric community-acquired pneumonia (CAP) management in Australian hospital emergency departments (EDs) and evaluate this against national guidelines, including use of the pneumonia severity index and antibiotic selection.

Design: A multicentre, cross-sectional, retrospective audit, April 2003 to February 2005.

Setting: 37 Australian hospitals: 22 principal referral hospitals, six large major city hospitals, four large regional hospitals, four medium hospitals and one private hospital.

Conditional rhythmicity of ventral spinal interneurons defined by expression of the Hb9 homeodomain protein.

The properties of mammalian spinal interneurons that underlie rhythmic locomotor networks remain poorly described. Using postnatal transgenic mice in which expression of green fluorescent protein is driven by the promoter for the homeodomain transcription factor Hb9, as well as Hb9-lacZ knock-in mice, we describe a novel population of glutamatergic interneurons located adjacent to the ventral commissure from cervical to midlumbar spinal cord levels. Hb9+ interneurons exhibit strong postinhibitory rebound and demonstrate pronounced membrane potential oscillations in response to chemical stimuli that induce locomotor activity.

Membrane receptors involved in modulation of responses of spinal dorsal horn interneurons evoked by feline group II muscle afferents.

Modulatory actions of a metabotropic 5-HT1A&7 membrane receptor agonist and antagonist [(+/-)-8-hydroxy-2-(di-n-propylamino)-tetralin; N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane-carboxamide] and an ionotropic 5-HT3 membrane receptor agonist and antagonist [2-methyl-serotonin (2-Me 5-HT); N-(1-azabicyclo[2.2.2]oct-3-yl)-6-chloro-4-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-8-carboxamide hydrochloride] were investigated on dorsal horn interneurons mediating reflex actions of group II muscle afferents.

The actions of monoamines and distribution of noradrenergic and serotoninergic contacts on different subpopulations of commissural interneurons in the cat spinal cord.

Modulatory actions of monoamines were investigated on spinal commissural interneurons which coordinate left-right hindlimb muscle activity through direct projections to the contralateral motor nuclei. Commissural interneurons located in Rexed lamina VIII, with identified projections to the contralateral gastrocnemius-soleus motor nuclei, were investigated in deeply anaesthetized cats. Most interneurons had dominant input from either the reticular formation or from group II muscle afferents; a small proportion of neurons had input from both.