Whisker-related circuitry in the trigeminal nucleus principalis: Topographic precision.

Single whiskers are topographically represented in the trigeminal (V) nucleus principalis (PrV) by a set of cylindrical aggregates of primary afferent terminals and somata (barrelettes). This isomorphic pattern is transmitted to the thalamus and barrel cortex. However, it is not known if terminals in PrV from neighboring whiskers interdigitate so as to violate rules of spatial parcellation predicted by barrelette borders; nor is it known the extent to which higher order inputs are topographic.

Changes in electrical perceptual threshold in the first 6 months following spinal cord injury.

Objectives: To investigate the use of electrical perceptual threshold (EPT) testing to follow the natural history of sensory progression after complete and incomplete acute spinal cord injury (SCI) and to compare EPT changes with the American Spinal Injuries Association (ASIA) Impairment Scale (AIS).

Study Design: Prospective descriptive study.

Methods: ASIA examination and EPT testing was performed on 17 patients (7 AIS A, 10 AIS B-D), within 1, 3, and 6 months after acute SCI.

Delayed olfactory ensheathing cell transplants reduce nociception after dorsal root injury.

Injury to cervical dorsal roots mimics the deafferentation component of brachial plexus injury in humans, with intractable neuropathic pain in the deafferented limb being a common consequence. Such lesions are generally not amenable to surgical repair. The use of olfactory ensheathing cells (OECs) for dorsal root repair, via acute transplantation, has been successful in several studies.

Selected changes in spinal cord morphology after T4 transection and olfactory ensheathing cell transplantation.

Spinal cord transection at T4 results in severe damage of the nervous tissue, with impairment of motor, sensory and autonomic functions. Transplantation of olfactory ensheathing cells (OECs) has the potential to improve these functions through a number of mechanisms, which include facilitation of regeneration and neuroprotection. For cardiovascular functions, we have previously shown that OECs reduce the duration of autonomic dysreflexia, without evidence of regeneration.

Effects of human OEC-derived cell transplants in rodent spinal cord contusion injury.

Numerous reports indicate that rodent olfactory ensheathing cells (OECs) assist in spinal cord repair and clinical trials have been undertaken using autologous transplantation of human olfactory ensheathing cells (hOECs) as a treatment for spinal cord injury. However, there are few studies investigating the efficacy of hOECs in animal models of spinal cord injury. In this study hOECs were derived from biopsies of human olfactory mucosa, purified by culture in a serum-free medium containing neurotrophin-3, genetically labelled with EGFP, and stored frozen.

Olfactory ensheathing cells reduce duration of autonomic dysreflexia in rats with high spinal cord injury.

Autonomic dysreflexia is a common complication in high spinal cord injury and can result in serious consequences and death. Here we have examined the effect of acute transplantation of olfactory ensheathing cells on cardiovascular functions in rats. After T4 transection, radio-telemetric recording in conscious animals was used to study blood pressure and heart rate at rest and during autonomic dysreflexia for up to 8 weeks post-injury.

Electrical perceptual threshold testing: a validation study.

Background/objective: To investigate inter-rater and intra-rater reliability of electrical perceptual threshold (EPT) testing in assessing somatosensory function in healthy volunteers.

Study Design: Prospective experimental.

Setting: Hospital-based spinal cord injuries unit.

Effect of treadmill training on autonomic dysreflexia in spinal cord--injured rats.

Background: Weight-supported treadmill training is an emerging rehabilitation method used to improve locomotor ability in patients with spinal cord injury (SCI). However, little research has been undertaken to test the effect of such training on other consequences of SCI, such as neuropathic pain and autonomic dysfunction.

Objective: This study investigates the effects of chronic treadmill training on the development of autonomic dysreflexia (AD), a form of cardiovascular dysfunction common in patients with cervical or high thoracic injury.

Local response to cold in rat tail after spinal cord transection.

Subjects with severe chronic spinal cord injury (SCI) are prone to hypothermia when they are exposed to relatively low environmental temperatures that are normally well tolerated by healthy individuals. This impaired thermoregulation is presumably due to disconnection of territories below the SCI from supraspinal thermoregulatory centers. However, it is not known how these territories respond to low temperatures.

Characterization of rat forepaw function in two models of cervical dorsal root injury.

Dorsal root injury (DRI) disrupts afferent input from the periphery and often leads to sensory deficits and neuropathic pain. Despite cervical root injuries in rodents being a useful model for deafferentation studies, a quantitative characterization of the sensory deficits produced by DRI is still lacking. This study aimed to characterize the different functional deficits resulting from a dorsal two- or four-root (C7-C8 and C5-C8, respectively) crush injury in rats at levels that innervate the forepaws.

Correlations between hand preference and cortical thickness in the secondary somatosensory (SII) cortex of the common marmoset, Callithrix jacchus.

Cortical asymmetries are well established in humans for language and motor regions and correlate with handedness. Here the authors investigate structural differences in the hemispheres of left- and right-handed common marmosets using surface photography and histology. The hand preferences of 11 marmosets were assessed over their adult life span using a simple reaching task.

Crash characteristics of older pedestrian fatalities: dementia pathology may be related to 'at risk' traffic situations.

Older people are over represented among pedestrian casualties, and cognitive decline is an often cited possible contributory factor. Cognitive decline and dementia are intimately associated, however the role dementia might play in older pedestrian crashes has received little attention. This study describes crash characteristics for 52 fatally injured older pedestrians in the Sydney metropolitan area.

Augmented locomotor recovery after spinal cord injury in the athymic nude rat.

The immune response contributes to ongoing secondary tissue destruction following spinal cord injury (SCI). Although infiltrating neutrophils and monocytes have been well studied in this process, T-cells have received less attention. The objective of this study was to assess locomotor recovery and tissue morphology after SCI in athymic (nude) rats, in which T-cell numbers are reduced.

Whisker maps in marsupials: nerve lesions and critical periods.

In the wallaby, whisker-related patterns develop over a protracted period of postnatal maturation in the pouch. Afferents arrive simultaneously in the thalamus and cortex from postnatal day (P) 15. Whisker-related patterns are first seen in the thalamus at P50 and are well formed by P73, before cortical patterns first appear (P75) or are well developed (P85).

Expression of cardiovascular and behavioural components of conditioned fear to context in T4 spinally transected rats.

A spinal cord transection at the fourth thoracic level (T4) results in paraplegia. It also removes supraspinal control of sympathetic outflow to most viscera and their blood vessels but spares the heart. We studied the effects of such a transection on the expression of the conditioned fear response to context, which includes freezing, 22 kHz ultrasonic vocalisations, a marked pressor response and a slowly rising tachycardia.

Spinal cord tissue affects ensheathing cell proliferation and apoptosis.

This study investigates proliferation and apoptosis of olfactory ensheathing cells in cocultures with spinal cord tissue. Proliferation of ensheathing cells was significantly increased when cocultured with explants from uninjured spinal cord, and spinal cord that had been subjected to chronic contusion or chronic needle stab injury, but not to acute needle stab injury. Proliferation rate was highest in cocultures with chronically stabbed cord tissue.

Effects of different anesthetics on the paired-pulse depression of the h reflex in adult rat.

Hyperreflexia is a common feature of spinal cord injury (SCI), and changes in reflex excitability have been reported to be useful in assessing treatments in animal models of cord damage. However, spinal reflexes are known to be dependent on anesthetic level. As a preliminary to its use in SCI, the excitability of the Hoffman reflex (H reflex) has been assessed under several commonly used anesthetics.

Axonal injury in children after motor vehicle crashes: extent, distribution, and size of axonal swellings using beta-APP immunohistochemistry.

The brains of 32 children (3 months to 16 years) who died as a result of motor vehicle collisions were examined for axonal injury using beta-APP immunohistochemistry. The extent and distribution of axonal injury was assessed and quantified throughout the forebrain, brainstem and cerebellum. The mean diameter of immunoreactive axons in the corpus callosum was measured for this pediatric group and, for comparison, a small adult sample.

Olfactory ensheathing cells promote locomotor recovery after delayed transplantation into transected spinal cord.

We demonstrated recently that transplantation of olfactory ensheathing cells from the nasal olfactory mucosa can promote axonal regeneration after complete transection of the spinal cord in adult rat. Ten weeks after transection and transplantation there was significant recovery of locomotor behaviour and restoration of descending inhibition of spinal cord reflexes, accompanied by growth of axons across the transection site, including serotonergic axons arising from the brainstem raphe nuclei. The present experiment was undertaken to determine whether olfactory ensheathing cells from the olfactory mucosa are capable of promoting regeneration when transplanted into the spinal cord 4 weeks after transection.