The objective of this study was to explore whether there was a functional link between trigeminal proprioception and the oculomotor system mediated through jaw muscle afferents.Electromyography（EMG） was undertaken o...The objective of this study was to explore whether there was a functional link between trigeminal proprioception and the oculomotor system mediated through jaw muscle afferents.Electromyography（EMG） was undertaken of the levator palpebrae（LP） and superior rectus（SR）,and Fos expression was detected in the brainstem following consecutive down-stretching of the lower jaw at 2-4 Hz in rats.Retrograde tracing was undertaken of the interstitial nucleus of Cajal and Darkschewitsch nucleus（INC/DN） pre-oculomotor neurons.FMG-like responses were recorded from the LP/SR during down-stretching of the lower jaw at 2-4 Hz in 3 out of 11 rats.Fos expression was induced by consecutive down-stretching of the lower jaw at 2-4 Hz for 20-30 seconds.Interestingly,Fos expression was distributed mainly in the bilateral INC/DN area.We also examined Fos-like immunoreactivity in central mesencephalic and paramedian pontine reticular formation that harbors premotor neurons controlling horizontal eye movement,but no Fos-like staining was observed therein.By injection of retrograde tracers into the oculomotor nucleus combined with Fos immunostaining,double labeled pre-oculomotor neurons were visualized to distribute in the INC/DN.In conclusions,there may exist a trigeminal proprioceptive-oculomotor system neural circuit through jaw muscle afferents in rats.Judging from Fos distribution pattern,this pathway might be related to vertical and torsional eye movements.展开更多
AIM: To make an electrophysiological demonstration of a possible jaw muscle afferents-oculomotor neural pathway that was proposed by our previous works on rats, which substantiates an early "release hypothesis&qu...AIM: To make an electrophysiological demonstration of a possible jaw muscle afferents-oculomotor neural pathway that was proposed by our previous works on rats, which substantiates an early "release hypothesis" on pathogenesis of human Marcus Gunn Syndrome(MGS). METHODS: Extracellular unit discharge recording was applied and both orthodromic and spontaneous unitary firing were recorded in the oculomotor nucleus(III), and the complex of pre-oculomotor interstitial nucleus of Cajal and Darkschewitsch nucleus(INC/DN), following electric stimulation of the ipsilateral masseter nerve(MN) in rats. RESULTS: Extracellular orthodromic unit discharges, with latencies of 3.7±1.3 and 4.7±2.9 ms, were recorded unilaterally in the III, and the INC/DN neurons, respectively. Spontaneous unit discharges were also recorded mostly in the INC/DN and less frequently in the III. Train stimulation could prompt either facilitation or inhibition on those spontaneous unit discharges. The inhibition pattern of train stimulation on the spontaneous discharging was rather different in the III and INC/DN. A slow inhibitory pattern in which spontaneous firing rate decreased further and further following repeated train stimulation was observed in the III. While, some high spontaneous firing rate units, responding promptly to the train stimuli with a short-term inhibition and recovered quickly when stimuli are off, were recorded in the INC/DN. However, orthodromic unit discharge was not recorded in the III and INC/DN in a considerable number of experiment animals. CONCLUSION: A residual neuronal circuit might exist in mammals for the primitive jaw-eyelid reflex observed in amphibians, which might not be well-developed in all experimental mammals in current study. Nonetheless, this pathway can be still considered as a neuroanatomic substrate for development of MGS in some cases among all MGS with different kind of etiology.展开更多
Introduction: Marcus Gunn jaw winking syndrome (MGJWS) is a rare congenital disorder belonging to the synkinetic eye movement group of disorders observed in children. It occurrence in adults and patients with diabetes...Introduction: Marcus Gunn jaw winking syndrome (MGJWS) is a rare congenital disorder belonging to the synkinetic eye movement group of disorders observed in children. It occurrence in adults and patients with diabetes has not been reported. Material and Methods: A 64 year man with poorly controlled diabetes of 18 years presented with 3 month history of jaw winking on the left side along with gustatory sweating, which was managed conservatively. There was spontaneous improvement in jaw wink at 4 months of follow up. Conclusions: Acquired causes of MGJWS are not known. This is probably the first report of this syndrome occurring at such a late age. Long standing poorly controlled diabetes may have had some role in the development of jaw winking in this patient.展开更多
基金partially supported by Natural Sciences Research Funding 2006C225 and 2009K0174 from Shaanxi Province awarded to Dr.Liang HC
文摘The objective of this study was to explore whether there was a functional link between trigeminal proprioception and the oculomotor system mediated through jaw muscle afferents.Electromyography（EMG） was undertaken of the levator palpebrae（LP） and superior rectus（SR）,and Fos expression was detected in the brainstem following consecutive down-stretching of the lower jaw at 2-4 Hz in rats.Retrograde tracing was undertaken of the interstitial nucleus of Cajal and Darkschewitsch nucleus（INC/DN） pre-oculomotor neurons.FMG-like responses were recorded from the LP/SR during down-stretching of the lower jaw at 2-4 Hz in 3 out of 11 rats.Fos expression was induced by consecutive down-stretching of the lower jaw at 2-4 Hz for 20-30 seconds.Interestingly,Fos expression was distributed mainly in the bilateral INC/DN area.We also examined Fos-like immunoreactivity in central mesencephalic and paramedian pontine reticular formation that harbors premotor neurons controlling horizontal eye movement,but no Fos-like staining was observed therein.By injection of retrograde tracers into the oculomotor nucleus combined with Fos immunostaining,double labeled pre-oculomotor neurons were visualized to distribute in the INC/DN.In conclusions,there may exist a trigeminal proprioceptive-oculomotor system neural circuit through jaw muscle afferents in rats.Judging from Fos distribution pattern,this pathway might be related to vertical and torsional eye movements.
基金Supported by Natural Sciences Research Funding from Shaanxi Province(No.2009K01-74)
文摘AIM: To make an electrophysiological demonstration of a possible jaw muscle afferents-oculomotor neural pathway that was proposed by our previous works on rats, which substantiates an early "release hypothesis" on pathogenesis of human Marcus Gunn Syndrome(MGS). METHODS: Extracellular unit discharge recording was applied and both orthodromic and spontaneous unitary firing were recorded in the oculomotor nucleus(III), and the complex of pre-oculomotor interstitial nucleus of Cajal and Darkschewitsch nucleus(INC/DN), following electric stimulation of the ipsilateral masseter nerve(MN) in rats. RESULTS: Extracellular orthodromic unit discharges, with latencies of 3.7±1.3 and 4.7±2.9 ms, were recorded unilaterally in the III, and the INC/DN neurons, respectively. Spontaneous unit discharges were also recorded mostly in the INC/DN and less frequently in the III. Train stimulation could prompt either facilitation or inhibition on those spontaneous unit discharges. The inhibition pattern of train stimulation on the spontaneous discharging was rather different in the III and INC/DN. A slow inhibitory pattern in which spontaneous firing rate decreased further and further following repeated train stimulation was observed in the III. While, some high spontaneous firing rate units, responding promptly to the train stimuli with a short-term inhibition and recovered quickly when stimuli are off, were recorded in the INC/DN. However, orthodromic unit discharge was not recorded in the III and INC/DN in a considerable number of experiment animals. CONCLUSION: A residual neuronal circuit might exist in mammals for the primitive jaw-eyelid reflex observed in amphibians, which might not be well-developed in all experimental mammals in current study. Nonetheless, this pathway can be still considered as a neuroanatomic substrate for development of MGS in some cases among all MGS with different kind of etiology.
文摘Introduction: Marcus Gunn jaw winking syndrome (MGJWS) is a rare congenital disorder belonging to the synkinetic eye movement group of disorders observed in children. It occurrence in adults and patients with diabetes has not been reported. Material and Methods: A 64 year man with poorly controlled diabetes of 18 years presented with 3 month history of jaw winking on the left side along with gustatory sweating, which was managed conservatively. There was spontaneous improvement in jaw wink at 4 months of follow up. Conclusions: Acquired causes of MGJWS are not known. This is probably the first report of this syndrome occurring at such a late age. Long standing poorly controlled diabetes may have had some role in the development of jaw winking in this patient.
