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. Following a 5 day interval, animals were anesthetised with urethane and a noxious mechanical stimulus was applied to the right hind paw. Animals were fixed by perfusion 5min following application of the stimulus. Retrogradely labelled SRT neurons of the lumbar spinal cord were examined for immunoreactivity for phosphorylated ERK (pERK) and the neurokinin-1 (NK-1) receptor. Approximately 15% of SRT cells in deep laminae (IV-VII and X) expressed pERK ipsilateral to the site of the stimulus. Around 60% of SRT cells with the NK-1 receptor expressed pERK but 5% of pERK expressing cells were negatively labelled for NK-1. It is concluded that a significant proportion of SRT cells projecting to the LRt respond to noxious mechanical stimuli and that one of the functions of this pathway may be to provide the cerebellum with nociceptive information.

Effect of intravenous immunoglobulin on cerebellar ataxia and neuropathic pain associated with celiac disease.

BACKGROUND: Cerebellar syndrome and small fiber neuropathy may complicate celiac disease (CD) and may be resistant to a strict gluten-free diet. METHODS: Case series. RESULTS: We report three patients with biopsy-proven CD who developed cerebellar ataxia and neuropathic pain despite strict adherence to a gluten-free diet. A small fiber neuropathy was suggested by skin biopsy findings in two patients. All patients' symptoms, including small fiber neuropathy symptoms, responded to treatment with intravenous immunoglobulin (IVIG). Discontinuation of IVIG in two patients resulted in worsened ataxia that reversed after resumption of IVIG. CONCLUSION: Intravenous immunoglobulin may be effective in treating cerebellar ataxia and small fiber neuropathy associated with CD, suggesting an immune pathogenesis. Further prospective, controlled studies are necessary to determine the long-term response to IVIG or other immunomodulation therapy.

Computerized posturography with sway frequency analysis: application in occupational and environmental health.

To examine the effects of occupational and environmental neurotoxicants on vestibular, cerebellar and spinocerebellar functions, the following three groups of subjects were examined, using a computerized posturography with sway frequency analysis: (1) 49 male chemical factory workers exposed to lead stearate, aged 27-63 (mean 43) years, with concurrent blood lead concentrations (BPbs) of 11-113 (mean 48) microg/100 g and past mean BPbs of 7-52 (mean 24) microg/100 g; (2) 29 male sandal, shoe and leather factory workers, aged 35-73 (mean 51) years, with urinary 2,5-hexanedione (HD) concentrations of 0.41-3.06 (mean 1.20) mg/g creatinine; and (3) 9 females, aged 19-58 (mean 29) years, who were exposed to sarin accidentally 6-8 months before the study (Tokyo Subway Sarin Poisoning, March 20,1995) and showed plasma cholinesterase (ChE) activities of 13-95 (mean 68) IU/l on the day of poisoning. The pattern of posturographic changes in lead workers suggested that the vestibulocerebellum (lower vermis), anterior cerebellar lobe and spinocerebellar afferent pathway were asymptomatically affected; the vestibulocerebellar change reflected concurrent lead absorption and the anterior cerebellar one reflected past absorption. Similarly, vestibulocerebellar and spinocerebellar functions were affected by n-hexane in solvent workers; the effect on the vestibulocerebellar function was probably inhibited by xylene. Also, the chronic (long-term) effect on the vestibulocerebellar function persisted in acute sarin poisoning. It is thus suggested that the vesitibulocerebellar function is most sensitive to all the three chemicals examined. It appears that the computerized posturography with frequency analysis is a useful technique for assessment of vestibular, cerebellar and spinocerebellar effects in occupational and environmental health.

Reduced pre-movement facilitation of motor evoked potentials in spinocerebellar degeneration.

OBJECTIVES: The aim of this study was to clarify the cerebellar effects on the motor area of the cerebral cortex and abnormal control mechanisms of voluntary movement in spinocerebellar degeneration (SCD). We used transcranial magnetic stimulation (TMS) to study the change in the motor evoked potentials (MEPs) before voluntary movement (pre-movement facilitation) in patients with SCD. SUBJECTS AND METHODS: Pre-movement facilitation of MEPs in subjects' muscles was observed during their thumb movement intention. Patients with SCD, who showed cerebellar signs, without pyramidal or extrapyramidal signs, were examined. TMS was applied randomly during the interval between the "go" signal and the onset of voluntary EMG. The MEPs were recorded from the abductor brevis pollicis muscle. RESULTS: Patients with SCD showed a delay of task performance. In control subjects, the amplitude of MEPs was significantly facilitated (increased) prior to voluntary movement. In patients with SCD, pre-movement facilitation of the amplitude of MEPs was significantly decreased in the study with subthreshold TMS. CONCLUSIONS: Disturbance of pre-movement facilitation in SCD may indicate incomplete cerebellar regulation of voluntary movements.