基于手指的触觉替代视觉系统的设计与实现

目的:设计与实现触觉替代视觉系统(TVSS),该系统尝试通过电极阵列刺激皮肤产生触觉感受,并利用触点的二维分布,为盲人开辟一条重获视觉信息的新途径.方法:系统由三个模块组成:多通道电触觉阵列,电极驱动电路以及嵌入式控制图像处理模块.其中256通道的电触觉阵列通过将球形镍电极焊接到印刷电路板上的方式制作而成.采用多路分时技术为多通道提供高压电脉冲刺激信号,通过光电隔离电路实现强弱电信号之间的隔离与控制.使用DM642开发板来实现图像的获取、处理以及传输功能.结果:手指尖电脉冲刺激的阈值在130V左右.结论:不同的刺激脉冲宽度,会引起刺激阈值以及刺激效果的变化,150 V以上的电脉冲会在指尖产生一个局部的舒适的电触觉感受.     

脉冲电刺激对血管内皮细胞与其祖细胞黏附的影响

为探索脉冲电刺激下血管内皮细胞与内皮祖细胞(EPC)之间黏附强度的改变,诱导培养外周血EPC,荧光标记后与单层血管内皮细胞共培养,固定电压和频率为5 V和5 Hz,选择1、3、6、9 ms的脉宽对其进行干预,持续刺激24 h后检测贴壁EPC的荧光强度,以荧光比率衡量。结果显示,与对照组相比,3 ms刺激组荧光比率即显著增高,随着脉宽延长,6 ms组达到最大值,但9 ms刺激组却显著下降,提示适宜脉冲电刺激有利于血管内皮细胞与EPC之间的黏附,为电刺激促进血管新生的研究提供新的理论依据。     

基于腔内压力评价的植入式结肠电刺激系统设计与动物实验

目的测试自行研制的植入式结肠起搏点电刺激系统对增加盲肠运动的效果。方法植入式结肠电刺激系统由植入式体内刺激器、便携式体外控制器和计算机参数设置分析软件组成。刺激参数及指令经体外控制器,以无线通信模式发送至体内刺激器;表征结肠收缩活动的压力信息由结肠腔内压力感受器采集后通过无线通信模式发送至体外控制器存储卡储存。选择46kg健康白猪1只,麻醉后开腹,将体内刺激器植入右侧腹股沟皮下,刺激电极穿过腹壁植入盲肠壁内固定,刺激参数选择电压为10、15、20 V,双脉冲频率为10、40、120 Hz,脉冲时间为0.5、1.0、3.0、5.0 ms,每次刺激前后连续观察记录5 min。检测完成后植入器固定,关腹后饲养1个月再次手术取出植入器。结果植入式结肠起搏点电刺激系统工作正常,在上述的电压、脉冲频率和双脉冲宽度的任意组合参数刺激下,发现电压和频率相同时脉宽越长,肠壁收缩活动的幅度越大;脉宽和电压相同时脉冲频率越高,肠壁收缩活动的潜伏期越短;频率和脉宽相同时电压越大,肠壁收缩活动的潜伏期越短,收缩幅度越大。在脉宽5.0ms、频率120Hz、电压15V的脉冲电刺激下,盲肠处于强直收缩状态。体内刺激器植入1个月,无感染及异物反应,取出时见植入物周围有少许包裹性积液。结论自行研制的电刺激系统初步适合进行结肠电刺激动物实验,选择合适刺激参数的结肠起搏点电刺激可明显增加结肠收缩运动,为进一步探索结肠电刺激治疗慢传输性便秘提供了研究基础。     

手术机器人面临的一大挑战———力触觉反馈

机器人手术作为一种微创手术技术,由于其高度的精准性,已经得到了外科医生的广泛认可。但机器人手术最大的局限之一就是外科医生缺乏操作的“手感”（即力触觉反馈）,增加了手术的不确定性和风险性,从而限制了手术机器人的进一步发展。文中从手术机器人力触觉反馈系统的组成、关键技术、以及当前的研究现状等几个方面,对该反馈系统进行了综述。力触觉反馈包括力反馈与触觉反馈。该系统的实现依赖力触觉的传感与再现,本文介绍了常用的力触觉传感器、再现设备及感觉模拟技术,并分析了各项技术的优缺点。对力触觉反馈系统在手术机器人的研究进展进行了概述。在汇总以前研究的基础上,对相关研究做了展望。     

不同刺激参数对SD大鼠肌肉收缩的影响

目的研究不同电刺激参数对SD大鼠肌肉收缩的影响,为临床应用电刺激治疗周围神经损伤提供参考。方法采用低频脉冲发射器对SD大鼠的颈项部肌群进行局部电刺激。刺激时改变频率、脉宽、电压及占空比等参数,观察参数变化对肌肉收缩及动物行为的影响。同时记录受刺激肌肉的肌电图。结果 8只SD大鼠在10~60Hz的频率范围内,随频率增加肌肉收缩率逐步增强。肌电图结果显示在刺激频率不变的前提下,随脉宽的增加（50~200μs）,肌电幅值显著上升,且肌电幅值的变化与大鼠行为改变成正相关。结论不同的刺激参数可影响肌肉的收缩状态与强度,选择合适的参数可使失神经支配肌肉发生有节律地收缩,防止肌萎缩,并有助于建立局部肌痉挛动物模型。     

电触听代偿仪的研制

本文主要介绍电触听代偿仪的设计和研制。系统采用８０９８单片机及相关的模拟和数字接口电路实现了声音信号实时采集、处理及触觉编码输出等功能。初步实验表明：通过使用本系统，受试者在经过训练后，屏蔽听觉能分辨出环境中的不同警示声如门铃声、汽车喇叭声等，能感受到语音的节律，能帮助其判断声源的方向。     

刺激脉宽对脉宽阈值积的影响

目的研究脉宽阈值积与刺激脉宽之间的关系,深化对电刺激听神经反应的认识。方法首先,根据已有的单根听神经刺激脉宽与阈值之间的表达式和电诱发复合动作电位(electrically evoked compound action potential,ECAP)刺激脉宽与阈值之间的表达式,推导出脉宽阈值积与刺激脉宽之间成线性关系。其次,利用Shepherd发布的实验数据与豚鼠实验数据进行研究,发现脉宽阈值积与脉宽的关系不能用简单的线性关系进行解释,其曲线中存在极值点。结果研究结果表明,由于实验结果中脉宽阈值积与刺激脉宽之间呈现较强的非线性特性,因此由刺激脉宽与阈值之间的关系式推导出的脉宽阈值积与脉宽之间的关系式与实验结果不符。结论需进一步研究刺激脉宽对听神经反应的影响,给出符合实验结果的表达式。     

自制用于麻醉药品实验的电脉冲刺激器

自制用于麻醉药品实验的电脉冲刺激器江苏省人民医院高敬文，殷雷我院麻醉科为了研究麻醉药物对气道平滑肌张力的影响，需要一台电脉冲刺激器，输出电脉冲，刺激肌肉组织收缩。脉冲刺激器输出要求：频率１０～７０Ｈｚ，脉宽０．３～３ｍｓ，输出峰－峰值１０～６０Ｖ，且...     

大鼠杏仁核快速电刺激点燃癫?模型的建立

目的：建立一种快速稳定的杏仁核电刺激点燃癫?模型。方法：选取SD雄性大鼠40只制作杏仁核点燃癫?模型,按随机化原则分为5组：A 组为空白对照组;B组刺激频率16 Hz ,波宽1．0ms、强度0．5mA,串长10个;C组刺激频率16Hz、波宽1．0ms,强度0．5mA,串长160个;D组刺激频率60Hz,波宽1．0ms,强度0．5mA,串长10个;E组采用刺激频率60Hz,波宽1．0ms,强度0．5mA,串长160个进行实验。利用这种不同频率、强度、串长电刺激杏仁核的模式寻找出最快速有效且稳定的点燃癫?模型的方法。结果：在全部大鼠中成功点燃23只（点燃成功率为72％）,然而在4种不同电刺激方法中,B组、C组、D组、E组的点燃成功率分别为100％、87％、87％和11％,B组与各组及组间比较差异有统计学意义（P＜0．01）。结论：本实验大鼠杏仁核电刺激可快速建立癫?模型,采用刺激频率16Hz、波宽1．0ms、强度0．5mA、串长10个的刺激参数,杏仁核快速点燃的效果最好。     

低场磁共振锁场谱仪的射频脉冲发生器研制

基于现场可编程阵列（FPGA）和数字频率合成（DDS）芯片设计一个磁共振锁场谱仪的射频脉冲发生器。通过软硬件结合的方法研制一个灵活可变的射频脉冲信号发生器,输出脉冲脉宽可调,输出脉冲时间调制精度可控制在μs级别,载波频率可达300 MHz,输出射频脉冲频率相位可调。通过仿真和实验测试,证明基于FPGA与DDS的射频脉冲发生器,可以有效激励低场磁共振锁场样品产生锁磁共振信号。     

Effect of tactile stimulation pulse characteristics on sensation threshold and power consumption

The psychophysical responses of human subjects to vibratory tactile stimulation of the skin were investigated experimentally. The parameters, of the waveform important to the minimization of power consumed by the tactile array of electromechanical vibrators and the maximization of the skin sensitivity to the stimulus were explored to develop optimum stimulation. Parameters investigated included the amplitude, frequency, and duty cycle of the current waveform used to drive the vibrators as well as the number of pulses per stimulating burst and the recovery time between bursts. Graphical techniques were used to determine, the optimal combination of the parameters which gave a stimulus that excited the skin to above tactile threshold while maintaining at a relative minimum the power required for the stimulus. The optimal stimulation waveform contains a burst of 10 rectangular pulses of 4% duty cycle separated by a period of nonstimulation of 2 s. Such a waveform can elicit a sensitivity of 29.4 mA⁻¹ consuming only 55 μW of power.     

Relationship between pulse rate and pulse width for a constant-intensity level of electrocutaneous stimulation

The relationship between pulse rate (PR) and pulse width (PW) for a constant level of electrocutaneous stimulation was ascertained using the method of comparative judgments. Twelve volunteer subjects were asked to adjust the PW of a Comparison Stimulus (S₂) until its intensity matched that of a Standard Stimulus (S₁) for which the PW was 200 μs and PR was 10 or 20 pulses per sec (pps). As expected, the experimental results indicate that the PW of a constant-current amplitude pulse train should decrease as its PR increases if a constant level of tactile stimulation intensity is desired. However, PW and PR were not linear-inversely related (p<0.005). Rather, their relationship was best described by a logarithmic equation: log PW=a+b log PR, where PW is in microseconds,a is 2.82,b is −0.412, and PR is between 1 and 100 pps. Utilization of this relationship during electrical stimulation of the skin sense will decouple the intensity component of the tactile sensation from its frequency component, thereby enhancing the potential comfort and clarity of this sensory communication interface.     

The structure and function of a slowly adapting touch corpuscle in hairy skin

1. Slowly adapting cutaneous mechanoreceptors, in the cat and primates, have been studied by histological and neurophysiological methods.2. Each touch corpuscle is a dome-shaped elevation of the epidermis, whose deepest layer contains up to fifty specialized tactile cells.3. Nerve plates, enclosed by the tactile cell (Merkel cells), are connected to a single myelinated axon in the dense collagenous core of the corpuscle.4. The corpuscle generated > 1000 impulses/sec when excited by vertical surface pressure. The response was highly localized and showed a low mechanical threshold, the frequency being dependent upon the velocity and amplitude of the displacement. There was a period of rapid adaptation before a sustained response which might continue for > 30 min.5. A quantitative analysis of the responses to excitation by displacements of differing amplitude, velocity and duration is included.6. The discharge of touch corpuscle units evoked by a mechanical stimulus was temperature-sensitive, and was enhanced by a fall in skin temperature.     

Modification of human pain threshold by specific tactile receptors.

The effects of conditioning vibrotactile stimulation of particular tactile receptor groups on thresholds to painful electric stimuli were studied in seven healthy adults. Preferentially Pacinian afferents were activated with conditioning sinusoidal vibration of 240 Hz at 20 and 200 micrometers amplitudes and preferentially non-Pacinian tactile fibers were activated with conditioning sinusoidal vibration of 20 Hz at 200 and 400 micrometers amplitudes. None of the subjects showed pain threshold elevation during activation of non-Pacinian tactile fibers. However, 6 of the 7 subjects showed significant pain threshold elevation with conditioning vibration stimulus of 240 Hz at 200 micrometers amplitude, and 4 subjects showed significantly elevated pain thresholds with conditioning stimulus of 240 Hz at 20 micrometers amplitude. It is concluded that the activation of Pacinian afferents causes inhibition of pain conducting pathways.     

Power requirements for vibrotactile piezo-electric and electromechanical transducers

Human-machine information transfer through tactile excitation has addressed new applications in virtual reality, robotics, telesurgery, sensory substitution and rehabilitation for the handicapped in the past few years. Power consumption is an important factor in the design of vibrotactile displays, because it affects energy needs and the size, weight, heat dissipation and cost of the associated electronics. An experimental study is presented on the power required to reach tactile thresholds in electromechanical and piezo-electric transducers. Three different waveforms are considered, with an excitatory period formed by a burst of rectangular 50% duty cycle pulses (R50), rectangular low duty cycle pulses (RLO) and sinusoidal pulses (SIN). Ten different pulse repetition periods (RPs) were considered in the range 1/550-1/25s. The voltage and current waveforms applied to the transducers at sensation thresholds in a group of 12 healthy subjects were sampled and stored in a digital oscilloscope. The average power was determined for each subject, and differences of two orders of magnitude were measured between the electromechanical and the piezo-electric transducer power consumption. Results show that, for the electromechanical transducer, a smaller power consumption of 25μW was determined for RP=1/25s and the RLO waveform. In the case of the piezo-electric transducer, power of 0.21 μW was determined for SIN excitation and RP=1/250s. These results show the advantages of reducing power requirements for vibrotactile displays, which can be optimised by the choice of appropriate types of transducer, excitatory waveforms and pulse repetition periods.     

应用肌电图仪对损伤周围神经行经皮电刺激治疗的方法与疗效评估

目的：评估应用肌电图仪进行经皮电刺激治疗对损伤周围神经功能恢复的促进作用,探讨电刺激治疗的最佳方法.方法：60例经神经电生理检查确诊腓总神经不全损伤的患者,男女不限,年龄20～35岁,采用随机数字表法将患者分为3组（n=20）,非电刺激治疗组（NS组）、电刺激治疗1组（S1组）、电刺激治疗2组（S2组）.NS组不给予电刺激治疗;S1组电刺激治疗每日10分钟,连续10天;S2组电刺激治疗每日10分钟,连续20天.3个月后复查腓总神经传导速度（NCV）与趾短伸肌复合肌肉动作电位（CMAP）波幅,比较3组患者治疗前后腓总神经电生理数据改善程度.结果：（1）NS组、S1组和S2组腓总神经NCV分别增加3.7±2.4 m/s、7.5±4.3 m/s和7.5±3.1 m/s,与NS组比较,S1组和S2组的腓总神经NCV均增加（P＜0.05）;与S1组比较,S2组的腓总神经NCV无增加（P＞0.05）.（2）NS组、S1组和S2组趾短伸肌CMAP波幅分别增加2.7±1.8mv、4.1±1.9mv和5.3±2.0mv,与NS组比较,S1组和S2组的趾短伸肌CMAP波幅均增加（P＜0.05）;与S1组比较,S2组的腓总神经CMAP波幅增加（P＜0.05）.结论：（1）经皮电刺激治疗对不全损伤周围神经功能的恢复有明显的促进作用,表现为NCV增快、CMAP波幅增加.（2）延长经皮电刺激治疗疗程有利于神经功能恢复.     

Modification of human pain threshold by specific tactile receptors

The effects of conditioning vibrotactile stimulation of particular tactile receptor groups on thresholds to painful electric stimuli were studied in seven healthy adults. Preferentially Pacinian afferents were activated with conditioning sinusoidal vibration of 240 Hz at 20 and 200μm amplitudes and preferentially non-Pacinian tactile fibers were activated with conditioning sinusoidal vibration of 20 Hz at 200 and 400 μm amplitudes. None of the subjects showed pain threshold elevation during activation of non-Pacinian tactile fibers. However, 6 of the 7 subjects showed significant pain threshold elevation with conditioning vibratory stimulus of 240 Hz at 200 μm amplitude, and 4 subjects showed significantly elevated pain thresholds with conditioning stimulus of 240 Hz at 20 μm amplitude. It is concluded that the activation of Pacinian afferents causes inhibition of pain conducting pathways.     

Visuotactile empathy within the primary somatosensory cortex revealed by short-latency afferent inhibition

Intersubjectivity entails the taking of another's perspective in order to understand their experience of the world. This perspective taking capacity extends to the intra-individual sharing of tactile experience. Previous studies have shown modulation of motor cortex excitability in response to the observation of aversive tactile stimulation to the hand of another person. Here we used transcranial magnetic stimulation (TMS) and peripheral stimulation to induce a short-latency afferent inhibition (SAI) effect, which we then sought to modulate via observation of non-noxious tactile stimulation to the hand of a model. Side congruency between the observed (model) and the recorded (participant) hand induced an increase of SAI and this effect was found to hold for motor-evoked potentials (MEPs) recorded from both left and right hands. Inhibition was not found with MEPs evoked using unconditioned pulses of TMS. These results demonstrate a sensorimotor response to observed non-noxious stimulation and suggest an empathic matching system for the tactile experiences of others.     

Long latency inhibition of H-reflex recovery by cutaneous tactile stimulation in man: a cutaneous transcortical reflex

The effect of cutaneous tactile stimulation on motoneuron excitability was studied in 20 normal subjects and in patients of hemiplegia (n = 14) and paraplegia (n = 15) by plotting H-reflex recovery curves during application of twin pulses alone ("basal" H-reflex recovery curve), and twin pulses synchronized with electrical stimuli evoking tactile sensation in skin over the lateral border of the small toe. The "basal" H-reflex recovery curves from normal subjects showed a significant lateral asymmetry of motoneuron excitability, with an even distribution of subjects showing greater excitability on the left and right sides. However, there was no relation between handedness and the side with greater excitability. The cutaneous stimulation produced a highly significant inhibition of the H-reflex recovery between 600 and 6000 ms, with the maximum inhibition recorded at 1000 and 2000 ms, at which time even a complete inhibition of the test H-reflex was observed in some instances. The effect of cutaneous stimulation before 600 ms was statistically insignificant. The amount of cutaneous inhibition of H-reflex recovery showed a lateral asymmetry. The side with greater motoneuron excitability showed more cutaneous inhibition of the H-reflex recovery. A comparison of the H-reflex recovery at higher frequencies of cutaneous stimulation with that at basal frequency showed a slight but statistically insignificant difference in the amount of cutaneous inhibition of the H-reflex recovery. In hemiplegics, the "basal" H-reflex recovery curves showed greater motoneuron excitability on the affected side as compared to those of the unaffected side or controls, with the late inhibitory phase being completely obliterated. A similar pattern was also observed in paraplegics. Significantly, the lateral asymmetry of motoneuron excitability observed in the control group was absent in paraplegics. The cutaneous stimulation failed to produce any significant effect on the H-reflex recovery curves either in the affected side of hemiplegics or in both sides of paraplegics. The significant long latency inhibition of the H-reflex recovery curve produced by cutaneous tactile stimulation is a new finding.(ABSTRACT TRUNCATED AT 400 WORDS)     

Electrophysiological analysis of the interaction between the lateral septum and the central nucleus of the amygdala

Evidence suggests that the lateral septum (LS) and the central nucleus of the amygdala (CeA) play opposing roles in the modulation of fear and anxiety. The current study examined the interaction of the two structures in the albino rat by electrically stimulating each and recording single-unit activity in the other. In each case, electrical stimulation consisted of 50 trains of 5 pulses 800 μA in amplitude, 0.1 ms in duration with a .01 s interval between pulses. Electrical stimulation of LS had a predominant inhibitory effect upon cells in CeA. Contrariwise, stimulation of CeA had a predominant excitatory effect on cells in LS. The results of the study suggest a possible regulatory, negative feedback model of the interaction between LS and CeA.