Identification and input-output properties of bulbar reticular neurons involved in the cerebral cortical control of trigeminal motoneurons in cats

Summary Neurons found in the medial bulbar reticular formation were activated by stimulation of the orbital gyms and responded with antidromic spike potentials to selective stimulation of either the masseter or anterior digastric motoneuron pool in the trigeminal motor nucleus in cats anesthetized with -chloralose. These two kinds of reticular neurons were assumed to be inhibitory neurons projecting to masseter motoneurons (IM neurons) and excitatory neurons projecting to anterior digastric motoneurons (ED neurons), involved in the effects of stimulation of the orbital gyrus on trigeminal motoneurons: inhibition of masseter motoneurons and excitation of anterior digastric motoneurons.Input-output properties of IM and ED neurons were studied intracellularly with the following results: (1) stimulation of the orbital gyrus evoked EPSPs in im and ED neurons with mono- and polysynaptic latencies; and (2) stimulation of the lingual nerve evoked a spike potential in a few IM and ED neurons after a rather long latency, indicating that the pathways involved in the cortical control of trigeminal motoneurons via IM and ED neurons were basically separate from those responsible for the reflex control by the peripheral inputsIntracellular injection of horseradish peroxidase revealed that both IM and ED neurons were small or medium in size and the former were smaller than the latter, while none of the large reticular neurons directly projected to the trigeminal motor nucleus. This suggests a possible functional differentiation among bulbar reticular neurons according to cell size.Supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

异体巩膜的眼库处理及在眼座植入术中的应用

目的　改良一种人异体巩膜的眼库处理方法,比较异体巩膜和自体巩膜在眼座植入术中应用的临床效果。方法　人异体巩膜的处理包括去除其它眼组织、灭菌、脱水、低温保存、复水等步骤。比较33 例用异体巩膜包裹羟基磷灰石眼座植入术与35 例自体巩膜包裹者和2 例自体加异体巩膜包裹者的临床效果、并发症。结果　异体巩膜包裹的眼座植入后的临床效果及并发症与自体巩膜组相似。结论　异体巩膜处理方法简单,临床使用安全,效果好     

Primary extramedullary orbital plasmacytoma in a child

We describe a rare case of extramedullary plasmacytoma of the orbit in an 11-year-old boy. Immunoperoxidase staining of the tissue was positive for IgG, chain and negative for chain. Serum and urine electrophoresis showed no M spike. Systemic examination and bone marrow aspirate failed to show generalised involvement. The tumour was completely excised and radiotherapy given postoperatively.     

经眶视神经管减压术的应用解剖学研究

目的:通过对视神经管及其周围结构的解剖学观测,为经眶视神经管减压术提供解剖学依据.方法:成人颅骨标本50个,观察视神经管与筛窦和蝶窦的关系;测量视神经管各壁的长度及视神经管颅口、眶口的垂直径和横径并计算截面积.甲醛溶液固定的成年尸头15个,观察视神经管颅口镰状襞、管内段视神经及眼动脉的关系.结果:视神经管的内侧壁最长,长度为(10.71±2.12)mm;视神经管眶口呈竖椭圆形,截面积为(25.84±5.43)mm2,视神经管颅口呈横椭圆形,截面积为(24.86±4.37)mm2.结论:(1)视神经管减压术应全程打开视神经管内壁;眶口的减压应充分.(2)管内段视神经鞘膜应否切开应根据情况而定,切开应避开视神经的营养血管,以切开鞘的内上壁较安全.     

Neuronal connections of orbital cortex in rats: topography of cortical and thalamic afferents

The cortical and thalamic afferent connections of rat orbital cortex were investigated using fluorescent retrograde axonal tracers. Each of the four orbital areas has a distinct pattern of connections. Corticocortical connections involving the ventral and ventrolateral orbital areas are more extensive than those of the medial and lateral orbital areas. The medial orbital area has cortical connections with the cingulate, medial agranular (Fr2) and posterior parietal (PPC) cortices. The ventral orbital area has connections with the cingulate area, area Fr2, secondary somatic sensory area Par2, PPC, and visual areas Oc2M and Oc2L. The ventrolateral orbital area (VLO) receives cortical input from insular cortex, area Fr2, somatic sensory areas Par1 and Par2, PPC and Oc2L. The lateral orbital area has cortical connections limited to the agranular and granular insular areas, and Par2. Thalamic afferents to the four orbital fields are also topographically organized, and are focused in the submedial and mediodorsal nuclei. The ventrolateral orbital area receives input from the entirety of the submedial nucleus, whereas the other orbital areas receive input from its periphery only. Each orbital area is connected with a particular segment of the mediodorsal nucleus. The medial orbital area receives its principal thalamic afferents from the parataenial nucleus, the dorsocentral portion of the mediodorsal nucleus, and the ventromedial portion of the submedial nucleus. The ventral orbital area receives input from the lateral segment of the mediodorsal nucleus, the rostromedial portion of the submedial nucleus and the central lateral nucleus. Thalamic afferents to the ventrolateral orbital area arise from the entirety of the submedial nucleus and from the lateral segment of the mediodorsal nucleus. The lateral orbital area receives thalamic afferents from the central segment of the mediodorsal nucleus, the ventral portion of the submedial nucleus and the ventromedial nucleus. The paraventricular, ventromedial, rhomboid and reuniens nuclei also provide additional input to the four orbital areas. The connections of the ventrolateral orbital area are interpreted in the context of its role in directed attention and allocentric spatial localization. The present findings provide anatomical support for the view that areas Fr2, PPC and VLO comprise a cortical network mediating such functions.     

Dependence of memory of meal time upon circadian biological clock in rats

Water intake was measured in rats under a free feeding schedule and under a meal feeding schedule (food was presented for 3 hours each day from 14:00 to 17:00 hr), both under LD condition. Both schedules allowed animals free access to water. Under the meal feeding schedule, drinking occurred mainly during the food presentation time, but it was also observed during the dark period, when food was not present. After 3 weeks of meal feeding, the rats were transferred to the free feeding schedule. They showed a habit of drinking at the meal time of the previous schedule (meal-feeding-induced drinking) up to 7 days of free feeding. When the rats were made blind in the transition from the meal feeding to the 2nd free feeding, the meal-feeding induced drinking occurred with a progressively increasing delay relative to the clock time, in the same way as seen with the nocturnal drinking. Rats with bilateral lesions of the suprachiasmatic nucleus did not show nocturnal drinking during the meal feeding schedule, and no signs of the meal-feeding-induced drinking were observed after the 2nd free feeding schedule was started. It was concluded that the persistence of the memory of the time of meal feeding in the following free feeding period could be traced with water-drinking as an index and such memory seems to be formed depending on the biological clock which is ascribed to activity of the suprachiasmatic nucleus under LD condition.     

Input from proprioceptors in the extrinsic ocular muscles to the vestibular nuclei in the giant toad,Bufo marinus

Summary Extracellular unit records were made from the left brain stem of decerebrate, paralysed giant toads (Bufo marinus) during passive movement of the ipsilateral eye. Units in the vestibular nuclear complex (VN) were identified by their short-latency responses to electrical stimulation of the anterior branch of the ipsilateral VIII cranial nerve.Of 58 units in the region of VN, as judged from field potentials to VIII nerve stimulation, fourteen gave phasic excitatory responses to passive movement of the eye and were also identified as vestibular nuclear units. A further twelve units which responded to eye-movement could not be assigned to VN; the remaining 32 units were in VN but did not respond to passive eye-movement. Also, of 16 units whose recording sites were identified histologically in the VN complex, 11 gave responses to vestibular nerve stimulation and to passive eye-movement and 5 responded to eye-movement only.Control experiments eliminated auditory, visual and cutaneous sources for the signal produced by passive eye-movement; thus, the signal must have arisen from intraorbital proprioceptors. Units in VN were also found which were excited by electrical stimulation of the intraorbital part of the fourth (trochlear) nerve; this provides strong evidence that proprioceptors in the extrinsic ocular muscles (EOM) are included in the receptors which provide the signal to VN during passive eye-movement.The effects of vestibular stimulation and of passive eye-movement were found to interact upon units in VN. When passive eye-movement and vestibular stimulation were paired the response to the second stimulus was significantly reduced over a range of interstimulus intervals.The conclusions are that orbital proprioceptive signals, including those from the EOM, project to the vestibular nuclei in the toad and, there, are able to influence processing of vestibular afferent signals. We suggest, therefore, that orbital proprioceptive signals may play a part in oculomotor control. The significance of the results is discussed in relation to the strategic position of the VN in the oculomotor control system.     

Zinc-rich afferents to the rat neocortex: projections to the visual cortex traced with intracerebral selenite injections

Infusion of sodium selenite to the occipital cortex of the rat was used for the specific tracing of zinc-rich pathways. Large numbers of labeled somata were found ipsilaterally in the visual, orbital and frontal cortices, and contralaterally in homotopic and heterotopic visual areas. Labeled neurons were also found ipsilaterally in the retrosplenial, parietal, sensory-motor, temporal and perirhinal cortex. In contrast to the cortico-cortical connections, ascending afferents to the visual cortex were not zinc-rich except for a few labeled neurons in the claustrum. Additional injections showed reciprocal zinc-rich connections between the visual cortex and the orbital and frontal cortices. The latter cortices also received ascending zinc-rich afferents from the claustrum. Selenite injections revealed the layered distribution and the morphology of these labeled neurons in the neocortex. Zinc-rich neurons were found in layers II–III, V and VI. However, none was found in layer IV. Zinc-rich somata appeared as pyramidal and inverted neurons. The contrasting chemical properties of cortical and subcortical visual afferents may account for the functional differences between these systems.     

利用ImageJ软件测量眼眶脂肪体积

目的建立一种精确测量眼眶脂肪体积的方法。方法应用Image J软件计算眼眶CT图像中的眼眶容积及眼眶脂肪体积,在提取眼眶边界时分别采用手工描计法及半自动方法。结果半自动方法与手工描计法计算结果大致相同,但更为精确与省时。结论 Image J软件可精确测量眼眶容积及眼眶脂肪体积。     

眼眶骨折眼球内陷手术前后直接眶压改变的研究

目的研究眼眶骨折眼球内陷患者的眶压改变及眼眶修复眼球复位手术对眶压及眼压的影响。探讨直接眶压检测的临床价值。方法自行设计并组装直接眶压测量仪。对40例单侧眼眶骨折眼球内陷患者手术前后进行直接眶压测量，同时测量眼压、间接眶压、眼球突出度和视力。结果眼眶骨折后直接眶压、间接眶压、眼压及眼球突出度均较正常侧降低，其中直接眶压的下降值与眼压的下降值之间有正相关关系(r^2=0．47)，间接眶压的下降值与眼球突出度的下降值之间有正相关关系(r^2=0．62)。术后直接眶压、间接眶压和眼压均比术前显著升高，三者的差值存在正相关关系。结论该直接眶压测量仪操作简便、结果准确、创伤小。眼眶修复眼球复位手术中进行直接眶压监测，可以评估眶内植入材料的数量及眶压改变，预防并发症的发生。