Research progress of methods for brain vigilance improvement / 生物医学工程学杂志

Vigilance is defined as the ability to maintain attention or alertness over prolonged periods of time. Since Mid-20th century, following the increasing man-machine communication, high level of vigilance has been demanded in many areas including driving safety, medical care and therapy, aerospace and military affairs, etc. Therefore, finding quick methods to improve the level of vigilance has become a key issue in medical study. Based on physical regulation, chemical regulation and physiological regulation, the research progress has been summarized in this paper. We, furthermore, also try to predict the future trend in this academic area and develop some tentative ideas about seeking more effective and convenient ways to improve the level of brain vigilance.

The research progress in brain vigilance detection / 生物医学工程学杂志

Vigilance is the body level of awareness for objective things. It has been used in security, medical and other fields since people used it as an objective indicator. Therefore automatical vigilance detection has become a major issue needed to be resolved as soon as possible. The methods of vigilance detection at home and abroad in recent years was analyzed in this paper, which will benefit the research and the people dedicated in vigilance detection.

The development of techniques for liquid level detection in auto clinical laboratory analyzers / 生物医学工程学杂志

Liquid level detection (LLD) is necessary for eliminating carry-over of needle's outside by limiting the depth the needle probes into liquid in auto clinical laboratory analyzers. This paper listed various demands of liquid-handling system under different situations; reviewed various LLD techniques, such as capacitive, air pressure, mechanical vibration, ultrasound, light reflection, CCD imaging etc.; briefly introduced the working principles, features, and limitation of the LLDs; and recapitulated the characteristics of contact and non-contact LLDs. Lastly, the next generation technique of LLD is prospected.

Correlation between white matter alterations and cognitive function decline in early Alzheimer's disease / 中华放射学杂志

ObjectiveTo investigate the effects of early stage Alzheimer's disease(AD)on white matter(WM)integrity using diffusion tensor imaging(DTI)and its relationship with cognitive function decline.MethodsDTI was performed in 32 subjects,including 14 early AD patients and 18 elder controls(ON)with a 1.5 T MR scanner. Fractional anisotropy(FA)and mean diffusivity(-D)values were computed and compared for 9 regions of interest(ROI).Eight standard neuropsychological tests were performed and compared between AD and ON to evaluate basic cognitive capacities of AD.Correlation analysis was applied between FA,(-D) values and scores of neuropsychological tests for all subjects.ResultsFA significantly decreased in splenium of the corpus callosum and the posterior parietal-temporal region(S2),and D significantly increased in the splenium in AD patients(P＜0.05).AD patients showed lower scores compared with ON in all neuropsychological tests(P＜0.05).FA of the splenium and S2 positively correlated with several tests scores,while (-D) of multiple ROIs negatively correlated with several tests scores (P＜0.05).ConclusionsIn the early stage of AD,neuropathology has effect not only on cognitive function,but also on white matter structure,and they have strong relationship.AD patients show white matter changes in specific regions,which reflect loss in cortico-cortical connections.

Research on effect of sleep deprivation on cognitive brain function / 生物医学工程学杂志

Research on the effect of sleep deprivation (SD) is an approach to shedding light on the working mechanism of sleep for cognitive brain function. To explore how SD affects cognitive function, a number of measures involving psychology, brain imaging and electrophysiology, have been adopted in this area. Research groups from domestic and verseas have focused on many aspects of cognitive science and have acquired initial results, but uniform conclusion has not been made because of mixed factors. Starting from the mechanism of SD, this paper summarizes the progress in the search of effect of SD, including the neurophysiologic change by brain imaging and the use of EEG for evaluating the decline of cognitive function, and then analyzes the main influential factors and orientation of future research in this area.

Influence of excessive internet use on auditory event-related potential / 生物医学工程学杂志

At present, young people's internet addiction has become a serious social problem and on important concern in China. Comparison studies of auditory event-related potential (ERP) between 9 excessive internet users and 9 common internet users were carried out. The obvious influences of excessive internet use on the users were observed. The result suggests that excessive internet use may have some influences on cerebral cognitive function.

The effect of excessive internet use on N400 event-related potentials / 生物医学工程学杂志

This investigation was made on the characteristic of the N400 event-related potentials in excessive internet users by analyzing the N400 difference between the excessive internet users (trial team) and normal subjects (control team); the aim was to provide a theoretic basis for the diagnosis and treatment of excessive internet users. Ten right-handed excessive internet users and ten healthy right-handed volunteers aged 20 to 25 years were recruited to attend the experimentation of single Chinese character with semantically matching or mismatching ending strokes. The N400 displayed obvious difference between the excessive internet users and normal subjects when they were confronted with mis-matching ending strokes of single simple Chinese character. The N400 amplitude of the trial team was significantly lower than that of the control team (P<0.05), and the N400 latency of the trial team was significantly earlier than that of the control team (P<0.05). In addition, the distribution of the N400 in the brain was more wide-spread in the control team than in the trial team. These results showed there was significant difference in N400 between the excessive internet users and the normal subjects.

The design of intelligentized FES system on ERD/ERS signals / 生物医学工程学杂志

Our objective is the designing of a functional electrical stimulation (FES) system on event related desynchronization (ERD) and event related synchronization (ERS) signals. When the brain images the left-and right-leg movements, the ERD/ERS signals will appear. By characterization and characteristic classification, the ERD/ERS will be translated into the response control signal for operating the FES system to electrically stimulate the legs of motor disability. The result shows that the experiment is successful in electrically stimulating the legs of motor disability.

Progress of study in auditory event-related potentials of novel events / 生物医学工程学杂志

This is a review of the progress in the study on auditory event-related potentials (ERP) of novel events. Several cognitive problems about the novelty ERP response on brain and the experiment methods are introduced. The mismatch negative potential (MMN) reflects the detection of deviant events, and MMN is related with the novelty P3. Familiarity and attention influence the novelty ERP response. Experiments results showed that the amplitude of ERPs in the frontal area was reduced with the enhancement of familiarity, while that in the parietal area had little change. Attention was helpful in increasing the amplitude of ERPs, and could make the corresponding brain area active. The functional significance of the response of ERP was discussed also.

Development of the study on emotion and electrophysiology / 生物医学工程学杂志

In this paper the state of emotion study using electroencephalogram is systemically introduced. The methods for emotion study including the analyses of EEG frequency spectrum, evoked potentials, event-related potentials and the non-linear dynamical analysis are summarized, and the latest development is reviewed. Lastly the effect of emotion on other brain functions, e.g. memory, is discussed. In the paper the developments of emotion studies are also predicted.

Visualization of neuronal fiber tracts in white matter based on diffusion tensor / 生物医学工程学杂志

In this paper, the basic principal or rational of diffusion tensor imaging (DTI), which develops rapidly in the field of functional magnetic resonance imaging study, is introduced. And how to reconstruct the imaging of neuronal fiber tracts in white matter with the data of DTI is described. The technique of tractography, its advantages and disadvantages are analyzed. Finally, the limitations and further applications of neuronal fiber tracts visualization are discussed.

Human excited electroencephalogram model and its location in brain / 生物医学工程学杂志

The aim of this study was to identify the characteristics of human excited electroencephalogram and the excited location in brain. The subjects were excited by taking a fixed quantity of caffeine. Electroencephalographic signals were collected using with 128 channels Phoenix Digital EEG and compared before and after the subjects drank coffee. The results showed obvious differences and compared with the ones before being excited electroencephalogram. After being excited we found that the lower frequency composition was restrained in the region below 10 Hz, the high frequency composition was increased significantly,and a wave crest of 38 Hz was produced in every acquisition point with the height around 200. Then the excited region was located in brain with the software of ASA 3 Course (designed by ANT company of Germany) and found that the excited location was focused on the area of the middle abdomen in the pons' side near bulbar when a person was exciting.

A novel biologic electricity signal measurement based on neuron chip / 生物医学工程学杂志

Neuron chip is a multiprocessor with three pipeline CPU; its communication protocol and control processor are integrated in effect to carry out the function of communication, control, attemper, I/O, etc. A novel biologic electronic signal measurement network system is composed of intelligent measurement nodes with neuron chip at the core. In this study, the electronic signals such as ECG, EEG, EMG and BOS can be synthetically measured by those intelligent nodes, and some valuable diagnostic messages are found. Wavelet transform is employed in this system to analyze various biologic electronic signals due to its strong time-frequency ability of decomposing signal local character. Better effect is gained. This paper introduces the hardware structure of network and intelligent measurement node, the measurement theory and the signal figure of data acquisition and processing.

Development of the ultrasonic characterization of biological tissue elasticity / 生物医学工程学杂志

The variation of tissue elasticity or stiffness is related with diseases of tissue, so the characterization of tissue elasticity is important to diagnosis. There are four methods for ultrasonic characterization of tissue elasticity: imaging inspection techniques, vibration velocity measurements, quasi-static strain measurements and parametric methods. The theories of the method of vibration velocity measurements and the method of quasi-static strain measurements and their new developments are discussed in this paper. The applications and the problems of this technique are discussed also.

Effect of magnetic field simulating electroencephalogram rhythm on memory / 中国组织工程研究

BACKGROUND: Recently, many researches suggest that transcranial magnetic stimulation has effect on learning and memory. Moreover, the effects of magnetic fields simulating electroencephalogram (EEG) rhythm on memory have been investigated.OBJECTIVE: To explore the effect of magnetic field simulating EEG rhythm on memory retrieval ability and its mechanism.DESIGN: Randomized controlled study.SETTING: Department of Medical Imaging, Tianjin Medical University,and School of Precision Instrument & Photoelectronic Engineering, Tianjin University.MATERIALS: The experiment was conducted at the Electroscopic Center of TianjSn Medical University and Laboratory of Biomedical Engineering Department of Tianjin University from February 2002 to February 2004.Totally 25 Wistar rats and 5 domestic cats were selected from the Experimental Animal Center of Tianjin Medical University.INTERVENTIONS: All the 25 Wister rats were randomly divided into 5 group, 4 experimental groups and one control group with 5 rats in each group. Magnetic field simulating EEG rhythm was used to stimulate Wistar rats in the 4 experimental groups, but the time and frequency rate were different. Group 1 was stimulated by weak magnetic field with frequency in α rhythm (10 Hz); Group 2 was stimulated by weak magnetic field with frequency in β rhythm (20 Hz); Group 3 was stimulated by weak magnetic field with frequency changing from α to β rhythm; and Group 4 was stimulated by weak magnetic field with frequency changing from β to α rhythm. Memory retrieval ability and changes of neurotransmitters in the brain were recorded. Five cats were treated with weak magnetic field with frequency changing from α to β rhythm for 20 minutes, and the changes of EEG power spectra before and after stimulation were compared.information from long-term memory was tested with modified cross maze;hippocampus of the rats was measured with high performance liquid multiple-channel electrophysiological recording device.Comparison of memory retrieval ability: Memory retrieval ability in Group 2 and Group 4 was obviously higher than that in control group 5 hours after Content ofdopamine (DA) in rats' cerebral hippocampus: It was obviously higher in the 4 experimental groups than in control group [(192.72±18.66,percentage of power spectrum of β rhythm was increased after stimulation [(23.0±3.4, 14.2±1.3) %.].CONCLUSION: Most of the weak magnetic fields simulating EEG rhythm of human brain can decrease the retrieval of long-term memory, but magnetic field with special rhythm may increase memory retrieval ability.All the effects are related to the release of hippocampal neurotransmitters which is mediated by the change of intracellular calcium ([Ca2+]i) and synaptic vesicle.

Synchronization of the activity of gamma oscillation and ERP components / 生物医学工程学杂志

In the present study the activity of the gamma oscillation synchronized with the stimuli and ERP is investigated by means of unimodal and bimodal experiments. The multiresolution wavelet algorithm is used for signal extraction and Gabor transform is employed to represent the temporal evolution of the selected frequency components. The results show that the gamma oscillation is strongly phase-locked not only with the exogenous stimuli in the three experiments, but also with the endogenous components of ERPs (N2b, P300). And the ERP and the gamma oscillation induced by the bimodal stimuli show the audio-visual bisensory integration and relationship. In addition, the results from the experiments with the auditory stimuli show that the gamma oscillation may be closely related to the perception of auditory signals.

Discrimination between left and right hand movement imagery event-releated EEG pattern / 生物医学工程学杂志

Left and right hand movement imagery can modifty the neural activity in the primary sensorimotor areas in a very similar way as observable with a real executed movement, leading to the special changes of EEG components such as event-related desynchronization/synchronization (ERD/ERS). Quick and correct classification of these event-related EEG pattern can be used to help patients with severe paralysis to move a cursor or orthosis to replace impaired motor function and provide a new communicatoion channel to environment. In this paper left and right hand movement imagery experiment method was introduced, some kinds of classification methods for event-related EEG pattern during motor imagery were reviewed and the prospect of classification methods was also put forward.

Technical progress of the ECT device / 医疗卫生装备

This paper introduces the technical progress of the emission computed tomography (ECT) device in these years. As the latest technical advance and applications in nuclear medicine imaging, the features, performances and applications of CTs of dual-head coincidence (DHC) single photon emission computed tomography (SPECT) and positron emission computed tomography (PET) are discussed.

Study on the influence of simulative EEG modulation magnetic field on the discharge of median raphe nuclei / 生物医学工程学杂志

In this paper the response characteristic of the nerve fiber to the modulation magnetic field induction is studied by using the method of numeric simulation. It is found that the nerve fiber is sensitive to the low frequency modulated signal but not to the high frequency carrier wave. A simulative EEG signal generator is developed according to the change of EEG rhythm during the sleep. The simulative EEG square wave is modulated by high-frequency magnetic impulse. The modulation magnetic field is coupled into the rabbit's brain to study the influence of magnetic stimulation on the discharge of 5-hydroxytryptamine (5-HT) nerve cell. The experiment results demonstrate that discharge frequency of median raphe nuclei related to sleep changes significantly and the discharge becomes slow, which shows that magnetic stimulation can inhibit electrical activity of 5-HT nerve cell and provide a new way to improve insomnia.

Effect of modulated pulse magnetic fields on memory retention and retrieval ability of rats and its mechanism / 中华物理医学与康复杂志

Objective To explore the effect and the mechanism of modulated magnetic pulse fields on memory retention and retrieval ability of rats. Methods The influence of different pulsed magnetic fields on memory performance of rats was evaluated by using cross maze test, the morphological changes of neurons and nerve synapses in the hippocampus of rats were observed by the electronic microscopy. Results The 20 Hz modulated-pulse magnetic field impaired the memory retrieval ability and the memory retention significantly after 1 hour of exposure of the rats to it ( P 0.05). These influences on nerve tissues were also observed in rats underwent the 10Hz modulated magnetic stimulation, manifested as an initial increase in ability of memory in the first 24 hours after the stimulation, but no significant difference from the control was found. The influence of magnetic fields on memory depended on what the rats remembered. Conclusion Changes in the nerve synapses may be a main factor of mechanisms of the influence of pulse magnetic fields on memory ability of rats.