Difference in catalepsy response in inbred rats during chronic haloperidol treatment is not predictive of the intensity of behavioral hypersensitivity which subsequently develops

An animal model was utilized to explore the observed clinical association between a history of significant neuroleptic-induced parkinsonism and an increased incidence for the subsequent development of tardive dyskinesia. Catalepsy-sensitive Fisher rats and catalepsy-resistant Brown Norway rats were treated for 14 days with haloperidol at a dose of either 1 mg/kg or 5 mg/kg daily. Following a 7-day drug withdrawal period, rats were tested for behavioral hypersensitivity to acute challenge with apomorphine and then striate were assayed for ³H-spiroperidol receptor binding. Despite significant interstrain difference in catalepsy response to either neuroleptic dose, Brown Norway rats treated with 5 mg/kg developed behavioral hypersensitivity and D-2 receptor supersensitivity equivalent to that of the similarly treated Fisher rats. Catalepsy, a possible rat analog for neuroleptic-induced parkinsonism, therefore did not predict the intensity of those subsequent behavioral and receptor changes considered to result from chronic antagonism of striatal dopamine receptors and to possibly underlie tardive dyskinesia. Further studies are required to elucidate the less than obvious relationship between extrapyramidal behavioral effects of chronic neuroleptic treatment.     

Architecture and frontal cortical connections of the premotor cortex (area 6) in the rhesus monkey

The premotor cortex (area 6) has several architectonic sectors that can be delineated on the basis of cytoarchitectonic and myeloarchitectonic features. Area 6 may be broadly subdivided into a dorsal and a ventral sector at the spur of the arcuate sulcus. Dorsal 6 lacks a granular layer IV, but ventral 6 has an emergent layer IV that separates laminae III and V. Dorsal 6 has a higher myelin content than ventral 6. Dorsal area 6 is further subdivided into a caudal and a rostral sector on the basis of the presence of large pyramidal cells in the caudal but not in the rostral sector. The rostral sector of area 6 can be subdivided into a medial region distinguished from a more laterally situated area by the presence of more compact and darkly stained cells in layers III and V. Ventral area 6 can be subdivided into an upper and lower division. The upper part has more prominent pyramidal cells in layers III and V, and a better developed outer Baillarger band and vertical plexus than the lower division. The efferent and afferent connections of area 6 were studied with anterograde and retrograde tracers. The frontal connections of dorsal area 6 are restricted to neighboring dorsal frontal regions. Only the caudal sector of dorsal area 6 is connected with the motor cortex. In contrast, ventral area 6 is not only connected with the prefrontal cortex, but also directly with the motor cortex, the parainsular gustatory area, and with somatosensory areas in the frontal operculum. The widespread connections of ventral area 6 may be related to the specialization of the head, neck, and face structures that are represented ventrally within the premotor cortex.     

Estimate of motor conduction in human spinal cord: slowed conduction in spinal cord injury

By using motor evoked potential (MEP) created by transcranial electric stimulation over the motor cortex and F-wave measurement from the peripheral nerve stimulation, it is possible to estimate the spinal cord motor conduction velocity (SCMCV) in the diseased state. Twenty-four patients with spinal cord injury (SCI) between T1 and T11 neurological levels participated in this study. MEP in leg muscle was absent in all neurologically complete paraplegics. In 16 patients with neurologically incomplete SCI, MEP was obtained in 13 patients. The SCMCV estimated from C7 to T12 spinal levels was 32.1 (SD = 9.4) m/s. This was significantly slower than 63.3 (SD = 8.6) m/s in 40 normal controls. This noninvasive, indirect method is measurable, and can provide valuable electrophysiological data in the assessment of motor function in patients with SCI.     

Vagus nerve afferent and efferent innervation of the rat uterus: An electrophysiological and HRP study

To determine a possible brainstem connection with the uterus, a study with electrophysiological techniques and horseradish peroxidase (HRP) tracing was performed in the rat. Neurons of the nucleus of the tractus solitarius decreased in discharge frequency during cervicovaginal distension. HRP injections into the uterine walls resulted in the appearance of labelled cells in the nodose ganglion and in the dorsal motor nucleus of the vagus nerve. The results demonstrate a direct bidirectional vagal complex-uterus connection via the vagus nerve. Results are discussed in terms of a complex uterus control system in which the paraventricular nucleus might play an integrative role.     

Phrenic motoneuron morphology in the neonatal rat.

The morphology of neonatal rat phrenic motoneurons was studied following retrograde labeling with horseradish peroxidase, which resulted in Golgi-like fills of phrenic motoneuron somata and dendrites. At birth, these neurons have well-developed dendritic trees with many characteristics described for phrenic motoneurons in the adult rat. The dendrites form tightly fasciculated bundles that emerge from the phrenic nucleus primarily along four axes: ventromedial, ventrolateral, dorsolateral, and rostral/caudal, with smaller and more variable projections directly lateral and ventral. Although sparse, some dendritic appendages were also present, and in a few animals, somata clustering was apparent. The most significant difference between adult and neonatal rat phrenic motoneurons is in the extent to which medially and laterally projecting dendrites extend beyond the borders of the ipsilateral gray matter. In the neonate, unlike the adult, these dendrites project extensively past the gray/white border to the edge of the hemicord. Ventromedial dendrites occasionally cross to the contralateral ventral horn in the ventral white commissure and laterally projecting dendrites could be seen reaching the edge of the cord, turning and traveling rostrally or caudally for up to 100 microns. Phrenic motoneurons are not unique in having long dendrites at birth. A brief comparative study showed that neonatal cervical, thoracic, and lumbar motoneurons also have long dendrites that project to the medial and lateral borders of the hemicord.     

Safety assessment of a novel ingredient for removable chewing gum

Rev7™ is an indigestible gum polymer used for the manufacturing of chewing gum. It allows for the formulation of chewing gum with low adhesion; thus can be readily removed from surfaces such as sidewalks, clothing, carpets and furniture. In a toxicological safety assessment, Rev7™ was found to be non-mutagenic in the AMES assay. The highest concentration tested in a mouse lymphoma thymidine kinase locus gene mutation assay induced a slight but biologically relevant increase in mutations under non-metabolic activation conditions after 24 h. Because of this finding, a mouse micronucleus assay was performed, and the test article was found to be negative for inducing chromosomal damage. A 28-day repeated oral toxicity study resulted in a NOAEL of 80,000 ppm; the highest concentration tested. Rev7™ was found to be free from contaminants such as heavy metals, monomers, and solvents. Lastly, Rev7™ did not demonstrate skin-sensitizing properties in the murine local lymph node assay.     

Incidence and lifetime risk of motor neuron disease in the United Kingdom: a population-based study

Background and purpose:  To estimate the incidence and lifetime risk of motor neuron disease (MND) in a population-based sample in the United Kingdom.
Methods:  We identified new cases of MND during the period 1990–2005 in the General Practice Research Database, which includes clinical information from more than 3 million Britons enrolled with selected general practitioners. Individuals with a first medical diagnosis of MND recorded in the database were considered incident cases of the disease. The positive predictive value of the computer-based diagnosis was estimated through review of a sample of medical records from potential MND cases.
Results:  In the period 1990–2005, 830 new cases of MND were identified. Age-standardized incidence of MND was 2.6 per 100 000 persons per year in women (95% CI: 2.3, 2.8) and 3.9 in men (95% CI: 3.6, 4.3). Incidence for both sexes peaked between 75 and 79 years. The rate of MND in men was 54% higher than in women (95% CI: 33%, 77%). The lifetime risk of MND, adjusting for competing causes of death, was 1 in 472 (2.1 per 1000) in women and 1 in 350 (2.9 per 1000) in men. No increase in MND incidence over time was apparent.
Conclusion:  In this population-based database, we found that MND incidence is higher in men than women, peaking in both sexes between 75 and 79 years.     

Cognitive motor processes: The role of motor imagery in the study of motor representations

Motor imagery is viewed as a window to cognitive motor processes and particularly to motor control. Mental simulation theory [Jeannerod, M., 2001. Neural simulation of action: a unifying mechanism for motor cognition. NeuroImage 14, 103–109] stresses that cognitive motor processes such as motor imagery and action observation share the same representations as motor execution. This article presents an overview of motor imagery studies in cognitive psychology and neuroscience that support and extend predictions from mental simulation theory. In general, behavioral data as well as fMRI and TMS data demonstrate that motor areas in the brain play an important role in motor imagery. After discussing results on a close overlap between mental and actual performance durations, the review focuses specifically on studies reporting an activation of primary motor cortex during motor imagery. This focus is extended to studies on motor imagery in patients. Motor imagery is also analyzed in more applied fields such as mental training procedures in patients and athletes. These findings support the notion that mental training procedures can be applied as a therapeutic tool in rehabilitation and in applications for power training.     

术中脊髓运动功能的运动诱发电位监测与麻醉的关系

运动诱发电位(MEPs)作为一种神经电生理监测方法,已广泛应用于术中脊髓运动功能监测..经颅电刺激肌源性动作诱发电位(M-MEPs)在术中监测中应用最为广泛.不同MEPs监测方法以及麻醉药物均对M-MEPs有不同程度的抑制作用,低温亦对其产生影响,因此术中选择合适的麻醉方案尤为重要,并宜采用多脉冲电刺激技术,以期获得满意的监测结果.本文就MEPs的原理及监测方法、影响M-MEPs的因素、术中脊髓运动功能监测的应用及其局限性等方面作一综述.