电刺激家鸽中脑诱导运动的初步研究

用电刺激方法研究浅麻醉状态下家鸽中脑的不同区域诱发的行为反应,认识家鸽中脑运动相关脑区的空间编码规律。在中脑的半环隆枕(TOS)、丘间核等核团区域诱导出扇动翅膀、呼吸加快、羽毛倒伏等运动行为。     

刺激兔下丘脑室旁核诱发的心律失常与增压反应

在60只局麻与肌松剂制动的家兔,观察到用0.1—0.4mA,50Hz,1ms 的方波电刺激下丘脑室旁核(PV)能诱发频发性心律失常(包括室性与室上性期前收缩)及显著的动脉血压升高。与同侧的下丘脑外侧区(LHA)及腹内侧核(VMH)相比,刺激PV诱发期前收缩的次数更为频繁,增压反应幅度较大,且所需阈值亦较低。较低强度刺激LHA 在部分兔能引起血压下降与心率减慢,而PV 则一致地诱发增压反应。电刺激腓深神经能抑制刺激PV诱发的期前收缩,但在中脑中央灰质微量注射吗啡或电解毁损只能完全阻断刺激VMH诱发的期前收缩,而不能完全阻断PV诱发的期前收缩。这些结果提示,PV是下丘脑中诱发心律失常与血压增高的高反应区之一,并且可能具有不同于LHA或VMH的神经机制或下行神经通路。     

家兔延髓腹侧防御反应相关神经元

实验在25只乌拉坦(700m/kg)、氯醛糖(35mg/kg)麻醉,肌肉麻痹,人工呼吸的家兔上进行。第一组16只家兔中,单或双脉冲刺激下丘脑和中脑防御反应区,在延髓腹侧记录刺激所兴奋的单位。大部分单位分布于网状巨细胞核腹侧α部。52％的单位有自发放电活动。用阈下强度同时刺激下丘脑和中脑,97％单位有兴奋反应,提示家兔下丘脑和中脑防御反应区在延髓腹侧有聚合投射。第二组9只家兔中,在延髓腹表面单侧应用甘氨酸滤纸片或电凝损毁时,血压轻度下降,刺激下丘脑和中脑防御反应区引起的升压反应也部分被阻断。双侧应用甘氨酸或损毁,血压下降到脊动物水平,升压反应几乎完全被阻断。上述结果提示家兔延髓腹侧神经元在维持正常血压水平和在中继防御反应传出通路中起重要作用。     

电刺激猫中脑导水管周围灰质和中缝大核对脊髓背角神经元伤害性感受反应的抑制

1.在氯醛糖麻醉的猫上,观察了电刺激中脑导水管周围灰质(PAG)和中缝大核(NRM)对脊髓腰段背角神经元传入活动的影响。2.按照对刺激的反应型式,在背角记录到非伤害性低阈值传入、广动力范围、伤害性热敏以及高阈值传入诱发的自发放电抑制等四类神经元。3.刺激 PAG和 NRM对记录到的多数背角神经元皮肤传入反应有明显抑制效应,而对自发放电抑制性神经元产生去抑制。4.比较刺激两脑区的抑制效应:NRM 作用较PAG 强;PAG 活动对背角伤害性反应抑制的选择性较 NRM强;阿片肽拮抗剂-纳洛酮拮抗NRM刺激的抑制。5.这些结果提示PAG和NRM对脊髓的下行抑制,可能有一部分是通过不同神经机制实现的。     

DR全脊柱摄影技术在脊柱侧弯中的应用与优势

目的:探讨数字化X线摄影(DR)全脊柱摄像技术在脊柱侧弯中的应用和优势。方法:收集2012年2月至2013年6月于本院进行治疗的脊柱侧弯病例88例,应用数字化X线摄影(DR)技术对脊柱由上至下进行正位和侧位的扫描,均进行3次曝光,每两次曝光间隔均为9秒,曝光后通过图像拼接技术将患者脊柱图像进行拼接和重叠,形成全景图像,对全部患者的图像质量进行观察和评估。结果:所有入选病例中有84例患者图像清晰显示了脊柱侧弯的方向和角度、椎体和椎间隙、对称的椎弓根、根间距及对脏器的影响程度。其中1例因运动不合作出现伪影,3例曝光不足。全脊柱图像质量正位优秀率为92.43%,侧位优秀率为85.92%;全脊柱图像拼接正位优秀率为83.44%,侧位优秀率为86.58%。结论:数字化X线摄影(DR)技术应用上方便快捷,患者配合时间较短,图像质量较好,能够满足临床医生进行诊断和治疗,有助于患者预后康复情况的评估,值得在临床诊断中推广应用。     

猫下丘脑腹内侧核与旁中央中脑区神经联系的电生理学观察

用电脉冲刺激戊巴比妥钠麻醉和三碘季铵酚麻痹的31只猫的下丘脑腹內侧核(HVM),记录旁中央中脑区的平均诱发电位(AEP)。HVM 刺激点46个,旁中央中脑区引导点1046个,其中阳性反应点103个,快波反应151个,大多数为“峰电位式”快波。用逐渐增强的电脉冲刺激 HVM 可得等级式和“全或无”式两类反应。用不同频率的双刺激(PST)测试了111个 AEP 的反应性,其中有38个能跟随500Hz 以上的 PST,27个能跟随200—499Hz 的PST,46个仅能跟随199Hz 以下的 PST。给予短串刺激时,得到跟随500Hz 以上及500Hz以下的两类反应。这些结果提示 HVM 与旁中央中脑区之间既有经突触的投射又有直接的纤维连接。据计算,这些直接纤维的传导速度约为0.29—4.1m/s,相当于细有髓鞘和无髓鞘两类纤维。另外还描述了可能属于中枢轴突的某些传导特性。反映直接纤维连接的 HVM 刺激点与中脑中央灰质反应点的位置关系提示两者之间可能具有背腹侧方向的对应关系。     

褪黑素在特发性脊柱侧凸发生发展中的作用

尽管众多学者对青少年特发性脊柱侧凸近行了广泛研究,但其病因至今仍然不清楚。通过将雏鸡松果体切除,可诱导出与人类特发性脊柱侧凸患者具有相似解剖学特征的脊柱畸形。进一步实验发现,松果体切除术亦可以使2足鼠发生脊柱侧凸。因此,褪黑素(松果体主要的分泌产物)水平的降低与特发性脊柱侧凸的发生密切相关。许多学者对青少年特发性脊柱侧凸患者的褪黑素水平进行了测定,但并未得出一致的结论。目前,褪黑素在青少年特发性脊柱侧凸发生中的作用,还存在争议,需要进一步的研究。     

一道实验题的思维训练教学策略

例题：将青蛙脑破坏,保留脊髓,在脊柱下部打开脊椎骨,剥离出脊髓一侧的1对脊神经根（包含1个背根和1个腹根,见图）。分别电刺激背根与腹根均可引起蛙同侧后肢发生运动反应。背根与腹根合并成脊神经。     

室旁核在刺激中脑防御反应区诱发防御性升压反应中的作用

雄性ＳＤ大鼠,用乌拉坦（７００ｍｇ／ｋｇ）和氯醛糖（３０ｍｇ／ｋｇ）腹腔麻醉。实验结果：（１）每隔５ｍｉｎ电刺激中脑导水管周围灰质背侧部“防御反应区”（ｄＰＡＧ）,持续观察５０ｍｉｎ,可见恒定的升压反应。若电解毁单侧室旁核（ＰＶＮ）区。１ｈ后,电刺激中脑ｄＰＡＧ区诱发的升压反应幅度部分减小。而损毁穹隆部、下丘脑前部、下丘脑背内侧核、下丘脑腹内侧核则无上述效应。（２）电刺激或微量注射高半胱胺酸（ＤＬ     

刺激鲫鱼小脑腹外侧区诱发的Mauthner细胞兴奋性突触后电位

实验采用微电极胞内记录技术探查鲫鱼Mauthner细胞(M-细胞)对小脑刺激的电反应特征。电刺激鲫鱼小脑腹外侧部,可在双侧M-细胞胞体、腹侧树突和外侧树突近端记录到一种复合性兴奋性突触后电位(小脑诱发性EPSP)。小脑诱发性EPSP潜伏期较短(0.63±0.09 ms),持续时间较长(5.49±1.13 ms),幅度分级和刺激频率依从等特征。以较高强度刺激小脑常引起M-细胞顺向激活。多点胞内连续穿刺实验显示小脑诱发性EPSP起源于腹侧树突远端。实验结果提示,小脑-M-细胞通路可能包含一组长短不等的神经元链,它们根据链的短或长,由近及远依次投射在腹侧树突远端。     

Locomotion induced by non-contingent intracranial stimulation: comparison to psychomotor stimulant

Non-contingent experimenter-applied stimulation (nEAS) to the ventral mesencephalon, unlike contingent intracranial self-stimulation (ICSS), elicits high rates of general locomotion. This locomotion may be due to the nature of the presentation of stimulation, in that nEAS is non-contingent, while ICSS depends on a specific and focused response (e.g., bar pressing). Psychomotor stimulants also elicit high amounts of general locomotion, with the locomotion attributed to increased dopamine release. Interestingly, dopamine release decreases or is absent with repeated ICSS, but not nEAS. This suggests that the locomotion elicited by nEAS may be the result of DA release similar to that observed with psychomotor stimulants. To determine the relationship between locomotion induced by nEAS and psychomotor stimulants, locomotion elicited by nEAS was directly compared to that produced by cocaine, a psychomotor stimulant and indirect DA agonist. Six groups of rats were examined: (1) DA+ group: rats were implanted with a stimulating electrode in the ventral mesencephalon and activation of DA neurons was verified during surgery by monitoring DA release in the striatum; (2) DA- group: rats were also implanted with stimulating electrodes, but the location in the ventral mesencephalon did not elicit DA release; (3) 10-mg/kg cocaine group: rats were exposed to a low dose (10 mg/kg) of cocaine; (4) 40-mg/kg cocaine group: rats were exposed to a high dose (40 mg/kg) of cocaine; (5) saline group: rats were injected with saline; and (6) naive group: rats received no treatment. The topography of behavior was assessed in all rats during four periods: a pre-treatment baseline, treatment, early post-treatment, and a late post-treatment end point. The results suggest that locomotion elicited by nEAS was stereotypic, dependent upon DA release and similar, but not identical, to psychomotor stimulant-induced locomotion.     

Connections of the subthalamic and mesencephalic "locomotor regions" in rats

Responses of single neurons to stimulation of the subthalamic "locomotor region" were recorded extracellularly in the tegmentum mesencephali of rats. Latent periods of response of different neurons varied from 1 to 13 msec. The thresholds of the unit responses usually did not exceed the threshold for eliciting locomotion. The results are evidence of direct and oligosynaptic connections between the "locomotor regions" of the subthalamus and mesencephalon.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 9, No. 3, pp. 275–280, May–June, 1977.     

Neuronal activity of the lateral vestibular nucleus of the guinea pig evoked by tilting the animal about the longitudinal axis during locomotion

In experiments on decerebrate guinea pigs, the impulse activity of neurons of the lateral vestibular nucleus evoked by tilting the animal about the longitudinal axis was investigated under conditions of spontaneous and mesencephalon stimulation-evoked locomotor activity. In most investigated neurons, locomotor activity led to changes in their responses to adequate vestibular stimulation. The dominant reaction was intensification of such responses, which was observed in almost all vestibulospinal neurons and in 2/3 of cells not having descending projections. Responses were suppressed only in 1/4 of the neurons not projecting to the spinal cord. The changes in the evoked responses had an amplitude character; the lag of the changes in the discharge frequency relative to the acceleration that caused them was constant. It is suggested that intensification of dynamic reactions of vestibular neurons during locomotion provides maintenance of the animal's equilibrium during movements in space by various gaits and along different trajectories.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 23, No. 5, pp. 541–549, September–October, 1991.     

Locomotion induced by epidural stimulation in a decerebrated cat after spinal cord injury

The effect of partial and complete spinal cord transection (Th7–Th8) on locomotor activity evoked in decerebrated cats by electrical epidural stimulation (segment L5, 80–100 μA, 0.5 ms at 5 Hz) has been investigated. Transection of dorsal columns did not substantially influence the locomotion. Disruption of the ventral spinal quadrant resulted in deterioration and instability of the locomotor rhythm. Injury to lateral or medial descending motor systems led to redistribution of the tone in antagonist muscles. Locomotion could be evoked by epidural stimulation within 20 h after complete transection of the spinal cord. The restoration of polysynaptic components in EMG responses correlated with recovery of the stepping function. The data obtained confirm that initiation of locomotion under epidural stimulation is caused by direct action on intraspinal systems responsible for locomotor regulation. With intact or partially injured spinal cord, this effect is under the influence of supraspinal motor systems correcting and stabilizing the evoked locomotor pattern.     

Subthalamic lesions eliminate sexual behavior in the male rat

Electrical stimulation of parts of the subthalamus and mesencephalon produces coordinated stepping movements, and for this reason these areas are sometimes referred to as the subthalamic and mesencephalic "locomotor" regions. In this study we contrast the sexual behavioral effect of electrolytic destruction of these two regions in the male rat. Lesions of the mesencephalic locomotor region had no significant effect on male sexual behavior. In contrast, subthalamic lesions centered on the caudal zona incerta just dorsal to the subthalamic nucleus eliminated sexual behavior in 6 of 15 males. The sexual behavior of the remaining males was affected to a lesser degree, for the most part in accord with the extent of destruction to this "critical zone." Subthalamic lesions produced no obvious impairment in locomotion, posture, limb use, muscle tone or sensorimotor orientation. Even so, the fact that electrical stimulation of the subthalamus elicits coordinated stepping suggests that the region is linked with systems directly concerned with movement and locomotion. These links could be particularly important in the process by which sexual motivation is translated into sexual behavior.     

The electrophysiological actions of dopamine and dopaminergic drugs on neurons of the substantia nigra pars compacta and ventral tegmental area.

The dopaminergic neurons of the substantia nigra pars compacta and ventral tegmental area play a crucial role in regulating movement and cognition respectively. Several lines of evidence suggest that a degeneration of dopaminergic cells in the substantia nigra produces the symptoms of Parkinson's disease. On the other hand, a hyperactivity of the dopaminergic transmission in the brain induces dyskinesia, dystonia and psychosis. It is also well established that the euphoric and rewarding responses evoked by drugs of addiction, such as amphetamine and cocaine, are mediated by central dopamine systems. Electrophysiological experiments which study the activity of single dopaminergic neurons in the ventral mesencephalon have shown that dopamine and dopaminergic drugs reduce the firing frequency of these cells. This is due to the stimulation of D2-D3 autoreceptors and to a hyperpolarization of the membrane produced by an increase in potassium conductance. In addition, substances which increase the release (amphetamine), the synthesis (levodopa) or block the uptake (cocaine, nomifensine, amineptine) of dopamine in the brain inhibit the firing activity of the dopaminergic cells throughout dopamine-mediated mechanisms. In this review, we will briefly examine the literature concerning the physiological and behavioural responses caused by dopamine and dopaminergic agents on the dopaminergic neurons of the ventral mesencephalon. Our conclusion suggests that the electrophysiological actions of dopamine and dopamine-related drugs on dopaminergic cells in the ventral mesencephalon might be indicative of the pharmacological effects of these agents on the brain.     

Changes in collagen metabolism during the chronic electrical stimulation of the midbrain reticular formation

The content of 11-hydroxycorticosteroids, free and bound hydroxyproline in the peripheral blood, as well as the level of free and net hydroxyproline in the aortic wall and myocardium of rabbits were studied in chronic prolonged electrical stimulation of the mesencephalon reticular system. The experiments have shown that electrical stimulation leads to the activation of adrenal cortex function and is accompanied by alterations in collagen metabolism, accumulation of collagen in the aorta and decreased collagen level in the myocardium.     

Hypothalamic unit responses to impulses from the hippocampus and mesencephalic reticular formation

The effect of stimulation of the dorsal tegmentum mesencephali and dorsal hippocampus on spontaneous single unit activity of the retrochiasmal (RCA), lateral (LHA), medial dorsal (MHAd) and medial ventral (MHAv) hypothalamic regions was investigated in acute experiments on rabbits. During repetitive mesencephalic stimulation many more neurons were activated in all parts of the hypothalamus than during hippocampal stimulation. During mesencephalic stimulation more neurons were excited than inhibited in LHA, MHAd, and MHAv, but in RCA more were inhibited. During hippocampal stimulation spontaneous activity was inhibited in many more cells than during mesencephalic stimulation. Neurons on which convergence of impulses from the hippocampus and mesencephalon was observed numbered 25% in RCA, 39% in LHA, 46% in MHAd, and 29% in MHAv of the total number recorded. By their action (inhibitory or excitatory) on the hypothalamic neurons the mesencephalon and hippocampus were antagonistic in 60% of cases in RCA, 78% in LHA, and 61% in MHAd.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 6, No. 5, pp. 489–495, September–October, 1974.     

Directional control and the functional organization of defensive responses inAplysia

Noxious cutaneous stimulation of anterior sites on Aplysia californica causes withdrawal and turning followed by escape locomotion. Stimulation of anterior sites causes significantly larger turning responses than does stimulation of posterior sites, so that escape locomotion is always directed away from a site of 'attack'. Later phases of escape locomotion are often the same, regardless of the site of the triggering stimulus. The defensive secretions, ink and opaline, are directed along the anterior-posterior axis at the source of noxious stimulation. Ink and opaline ejections are directed to the front or back of the animal by characteristic responses of the siphon, mantle, and parapodia. Ink and opaline are ejected by a series of coordinated pumping movements of the mantle, gill, and parapodia that closely resemble triggered 'respiratory pumping' or 'Interneuron II' episodes (Kupfermann and Kandel 1969; Byrne and Koester 1978; Hening 1982). The directed ejection of secretions from the mantle cavity in response to noxious stimulation suggests a number of potential defensive functions for these secretions including aggressive retaliation, startle display, diversion, and alarm signalling (Edmunds 1975). Taken together, our results and others' suggest an integrated scheme for the functional organization of overt defensive behavior in Aplysia, and begin to suggest testable hypotheses about the integration of defensive responses on the cellular level in this animal.     

Probing diversity within subpopulations of locomotor‐related V0 interneurons

The V0 interneuronal population is derived from Dbx1 expressing progenitors. Initial studies on these interneurons in the mouse spinal cord demonstrated that they project commissural axons and are involved in coordinating left‐right alternation during locomotion. Subsequent work has indicated that the V0 population can be divided into genetically distinct ventral (V0_V) and dorsal (V0_D) subpopulations, and experimental evidence suggests that each is responsible for left‐right alternation at different locomotor speeds. In this study, we perform a series of experiments to probe the location and connectivity of these subpopulations in neonatal mice and demonstrate that they are more diverse than previously predicted. While the distribution of either subpopulation remains consistent along the extent of the lumbar spinal cord, a cluster of V0_D cells lateral to the central canal receive substantial input from primary afferents. Retrograde tracing and activity dependent labeling experiments demonstrate that a group of V0 interneurons located in this same region preferentially project axons towards contralateral motoneurons via an oligosynaptic pathway, and are active during fictive locomotion. Our results suggest that this subset of V0 interneurons may be primarily responsible for coordination of left‐right alternation during locomotion. Furthermore these experiments indicate that while genetic identity is one determinant of the function of a neuron during locomotion, the specific position in which the cell is located may also play a key role. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1189–1203, 2015