Improved emotional stability in experienced meditators with concentrative meditation based on electroencephalography and heart rate variability.

OBJECTIVE: To determine whether emotional stability distinguishes how experienced and novice meditators react to visual stimuli. DESIGN: PARTICIPANTS practiced concentrative meditation and then responded to visual stimuli while continuing to meditate. PARTICIPANTS: Ten experienced and 10 novice meditators responded to sequences of visual stimuli after concentrative meditation. RESULTS: As predicted, both groups had increased parasympathetic activities during concentrative meditation. Experienced meditators had increased low-frequency electroencephalography (EEG) rhythms in response to visual stimulation, whereas novices had increased high-frequency EEG rhythms. Correlational analyses revealed that novice meditators changed from a meditative state to a nonrelaxed state when the visual stimuli were presented, whereas experienced meditators maintained the meditative state. CONCLUSION: The study provides evidence that regular concentrative meditation can improve emotional stability and that recording physiologic responses to visual stimuli can be a good method for identifying the effects of long-term concentrative meditation practice.

Accumulated mental stress study using the meridians of traditional Chinese medicine with photoplethysmography.

OBJECTIVES: To investigate accumulated mental stress according to the concept of the meridians of Traditional Chinese Medicine (TCM). This stress was quantified by using pulse spectrum analysis of finger-tip photoplethysmography (PPG). Stress accumulation is one of the main causes of cardiovascular disease and depression in humans, resulting in chronic physiologic malfunctions; however, few studies have thoroughly assessed the quantitative evaluation of accumulative stress using the concept of TCM. DESIGN: This study investigated accumulated mental stress from the perspective of TCM based on an 8-day experiment. The theory of organ resonance was integrated into the proposed PPG sensing instrument to capture the nine harmonics of TCM. Participants were given daily mental arithmetic tasks over 1 week to simulate stress accumulation, and trends in the proportion of the nine harmonics of TCM were extracted over several days and analyzed to identify the affective factors related to cumulative stress. RESULTS: The experimental results showed that the kidney harmonic proportion (C2) and stomach harmonic proportion (C5) were significant only on the first few days because of a physiologic phenomenon of temporary stimulation. Most important, the trend of the liver harmonic proportion (C1) from days 3 to 8 dramatically increased and became gradually saturated because of the influence of accumulated mental stress. CONCLUSIONS: The results strongly suggest that pulse spectrum analysis of the PPG signal provides physiologically and pathologically important information on accumulated mental stress and can be useful for TCM analysis.

A three-lead, programmable, and microcontroller-based electrocardiogram generator with frequency domain characteristics of heart rate variability.

The objective of this study is to design and develop a programmable electrocardiogram (ECG) generator with frequency domain characteristics of heart rate variability (HRV) which can be used to test the efficiency of ECG algorithms and to calibrate and maintain ECG equipment. We simplified and modified the three coupled ordinary differential equations in McSharry's model to a single differential equation to obtain the ECG signal. This system not only allows the signal amplitude, heart rate, QRS-complex slopes, and P- and T-wave position parameters to be adjusted, but can also be used to adjust the very low frequency, low frequency, and high frequency components of HRV frequency domain characteristics. The system can be tuned to function with HRV or not. When the HRV function is on, the average heart rate can be set to a value ranging from 20 to 122 beats per minute (BPM) with an adjustable variation of 1 BPM. When the HRV function is off, the heart rate can be set to a value ranging from 20 to 139 BPM with an adjustable variation of 1 BPM. The amplitude of the ECG signal can be set from 0.0 to 330 mV at a resolution of 0.005 mV. These parameters can be adjusted either via input through a keyboard or through a graphical user interface (GUI) control panel that was developed using LABVIEW. The GUI control panel depicts a preview of the ECG signal such that the user can adjust the parameters to establish a desired ECG morphology. A complete set of parameters can be stored in the flash memory of the system via a USB 2.0 interface. Our system can generate three different types of synthetic ECG signals for testing the efficiency of an ECG algorithm or calibrating and maintaining ECG equipment.

Development of a multitarget tracking system for paramecia.

This investigation develops a multitarget tracking system for the motile protozoa, paramecium. The system can recognize, track, and record the orbit of swimming paramecia within a 4 mm diameter of a circular experimental pool. The proposed system is implemented using an optical microscope, a charge-coupled device camera, and a software tool, Laboratory Virtual Instrumentation Engineering Workbench (LABVIEW). An algorithm for processing the images and analyzing the traces of the paramecia is developed in LABVIEW. It focuses on extracting meaningful data in an experiment and recording them to elucidate the behavior of paramecia. The algorithm can also continue to track paramecia even if they are transposed or collide with each other. The experiment demonstrates that this multitarget tracking design can really track more than five paramecia and simultaneously yield meaningful data from the moving paramecia at a maximum speed of 1.7 mm/s.

A force plate measurement system to assess hindlimb weight support of spinal cord injured rats.

This paper describes a force plate system for quantitative measurement of the hindlimb weight support of rats. The system is built around a microcontroller and uses strain gauges to measure individually the weight applied by each limb and also the general hindquarters of the rat. The sum of weights on the individual force plates adds up to the total weight of the rat. Mathematical comparison of the weights of the different force plates allows calculation of the weight percentage of the hindquarters (W%HQ=(hindquarters weight/total weight)x100%). When hindlimb impairment is high, the W%HQ is high and vise versa, allowing hindlimb weight support to be evaluated by the W%HQ. An actual laboratory embodiment is demonstrated and real experiments are performed on spinal cord damaged rats. W%HQ results are compared with Basso, Beattie, Bresnahan (BBB) locomotor behavioural test results on the same rats at approximately the same time. When a rat is placed in the correct position of the test chamber, the user can use a local keypad/LCD display (standalone mode) or the PC keyboard/display to control the system and access the current data. Comparing our results with those of the BBB method confirms the proposed hardware and W%HQ metric represent very well the recovery of a rat after spinal cord injury. Medical investigators report that under actual use, the presented system is stable, accurate and easy to use. Additional advantages of the presented force plate system include stand-alone capability, non-dependence on subjective human judgement and quantitative results.

A novel application of the S-transform in removing powerline interference from biomedical signals.

Powerline interference always disturbs recordings of biomedical signals. Numerous methods have been developed to reduce powerline interference. However, most of these techniques not only reduce the interference but also attenuate the 60 Hz power of the biomedical signals themselves. In the present study, we applied the S-transform, which provides an absolute phase of each frequency in a multi-resolution time-frequency analysis, to reduce 60 Hz interference. According to results from an electrocardiogram (ECG) to which a simulated 60 Hz noise was added, the S-transform de-noising process restored a power spectrum identical to that of the original ECG coincident with a significant reduction in the 60 Hz interference. Moreover, the S-transform de-noised the signal in an intensity-independent manner when reducing the 60 Hz interference. In both a real ECG signal from the MIT database and natural brain activity contaminated with 60 Hz interference, the S-transform also displayed superior merit to a notch filter in the aspect of reducing noise and preserving the signal. Based on these data, a novel application of the S-transform for removing powerline interference is established.

Video tracking algorithm of long-term experiment using stand-alone recording system.

Many medical and behavioral applications require the ability to monitor and quantify the behavior of small animals. In general these animals are confined in small cages. Often these situations involve very large numbers of cages. Modern research facilities commonly monitor simultaneously thousands of animals over long periods of time. However, conventional systems require one personal computer per monitoring platform, which is too complex, expensive, and increases power consumption for large laboratory applications. This paper presents a simplified video tracking algorithm for long-term recording using a stand-alone system. The feature of the presented tracking algorithm revealed that computation speed is very fast data storage requirements are small, and hardware requirements are minimal. The stand-alone system automatically performs tracking and saving acquired data to a secure digital card. The proposed system is designed for video collected at a 640 x 480 pixel with 16 bit color resolution. The tracking result is updated every 30 frames/s. Only the locomotive data are stored. Therefore, the data storage requirements could be minimized. In addition, detection via the designed algorithm uses the Cb and Cr values of a colored marker affixed to the target to define the tracked position and allows multiobject tracking against complex backgrounds. Preliminary experiment showed that such tracking information stored by the portable and stand-alone system could provide comprehensive information on the animal's activity.

Postural tremor and control of the upper limb in air pistol shooters.

A postural tremor appears whenever someone attempts to maintain a steady position against gravity. We examined the postural tremor that occurred while air pistol shooters were taking aim so as to compare the coordinative control of the shooters and to identify the features critical to successful shooting. Ten elite and ten pre-elite athletes participated in pistol shooting at 10 m, and the postural tremors in the pistol and upper limb were recorded with lightweight accelerometers. Exploratory analysis showed that the elite shooters had smaller tremor amplitudes than the pre-elite shooters in the pistol and distal arm segments. Compared with the pre-elite shooters, the elite shooters had a smaller tremor amplitude in the lateral direction relative to that in the vertical direction, together with weaker tremor coupling in the lateral direction and stronger vertical coupling of the pistol-hand complex. The resulting shot performance was inversely related to the amplitude of the tremor and to the 8-12 Hz spectral peak of the lateral tremor in the pistol-hand complex. We conclude that the postural tremors of air pistol shooters are associated with the skill of the shooters, and that the elite shooters could optimize the control of the pistol-hand complex, which strongly determined success in shooting.

An inclined plane system with microcontroller to determine limb motor function of laboratory animals.

This study describes a high-accuracy inclined plane test system for quantitative measurement of the limb motor function of laboratory rats. The system is built around a microcontroller and uses a stepping motor to drive a ball screw, which changes the angle of the inclined plane. Any of the seven inclination speeds can be selected by the user. Two infrared (IR) LED/detector pairs function as interrupt sensors for objective determination of the moment that the rat loses its grip on the textured flooring of the starting area and slips down the plane. Inclination angle at the moment of IR interrupt (i.e. rat slip) is recorded. A liquid crystal display module shows the inclination speed and the inclination angle. The system can function as a stand alone device but a RS232 port allows connection to a personal computer (PC), so data can be sent directly to hard disk for storage and analysis. Experiments can be controlled by a local keypad or by the connected PC. Advantages of the presented system include easy operation, high accuracy, non-dependence on human observation for determination of slip angle, stand-alone capability, low cost and easy modification of the controlling software for different types of experiments. A fully functional prototype of the system is described. The prototype was used experimentally by a hospital group testing traumatic brain injury experiments, and some of their results are presented for system verification. It is found that the system is stable, accurate and easily used by investigators.

Integrated digital image and accelerometer measurements of rat locomotor and vibratory behaviour.

This study developed a combined IC-type accelerometer and video camera system to simultaneously measure vibration and locomotion activities in rats. A personal computer, adopted as an image frame grabber, was combined with a digital image processing algorithm to measure the precise location of an animal in an experimental cage. An accelerometer-based vibration subsystem, based on an 89C51 single-chip microprocessor, was designed. The acceleration sensor module was attached directly to the shaved back of the rat's body to directly measure the animal's vibration. This module can detect a wide range of vibrations from movements of the entire body to micro-tremors. Along with hardware, this study also proposes novel software for video enhancement and data analysis to calculate the behaviour parameters from recorded movements. In normal mode, three vibration activities (locomotor activity, tremor and twitch) are auto-analyzed every 10 min. The results are saved, and various display, statistical and data organization options are available. The primary merits of this system are the ability to simultaneously record locomotion and vibrational data, the rapid set-up and operation, the low cost, the reduced illumination requirements, the reduction of environmental noise and the high precision. The proposed method will be of interest to researchers in various behavioural, biological and medical fields.

Age effect on fatigue-induced limb acceleration as a consequence of high-level sustained submaximal contraction.

In reference to electromyographic measurement, the study was conducted to reassess differences in the behavior of fatigue-related neuromuscular function between young and elderly humans with limb acceleration (LA). Fourteen young and fourteen elderly subjects performed sustained index abduction at 75% of their maximal voluntary contractions (MVC) until task failure. Measures of neuromuscular function, including temporal/spectral features of muscle activity of the first dorsal interosseous (FDI) and LA of the index and hand, were monitored. The results showed a manifest fatigue-induced increase in LA of the index in the elderly group, but not in the young group. In contrast, only the young group developed a significant increase in amplitude of the electromyography (EMG) until task failure. Spectral analyses of LA in the index reflected marked age-dependent reorganization following muscle fatigue, with a greater reduction of relative spectral amplitude of LA in the range of 20-40 Hz, but a lesser reduction in coherence between EMG and LA in the elderly group. In line with fatigue-associated restructuring of LA, the mechanical coupling of the metacarpophalangeal joint was more severely undermined in the elderly group than in the young group. The present study manifested an age-related difference in the relative contributions of neural versus mechanical factors to muscle fatigue. Subsequent to a high-level sustained submaximal isometric contraction, a predominant mechanical failure of the musculotendon complex in the elderly was featured with LA, whereas EMG measurement characterized prevailing impairment of neuromuscular propagation in the young.

Exertion dependent alternations in force fluctuation and limb acceleration during sustained fatiguing contraction.

The study was conducted to contrast exertion-dependent changes in electromyography (EMG), force fluctuation (FF), and limb acceleration (LA) during isometric contraction to attain a versatile picture of muscle fatigue. Fifteen volunteers performed sustained index abduction at 25 and 75% maximal voluntary contractions (MVC) until failure at the tasks; meanwhile, changes in temporal/spectral features of force, muscle activity of the first dorsal interosseous (FDI), and acceleration of the index and hand were monitored. The results showed a manifest increase in all recorded signals for the 25% MVC paradigm, especially for LA, which demonstrated the largest increment in amplitude. In addition to progressive enhancement of the mechanical coupling of the metacarpophalangeal (MCP) joint, the 25% MVC paradigm added to EMG-FF and EMG-LA coherences (CohEMG-FF and CohEMG-LA) at 8-12 Hz and the shift of the spectral peak of the LA to higher frequencies. In contrast, the 75% MVC paradigm did not modulate significantly the spectral peak of LA. Also, CohEMG-FF, CohEMG-LA at 8-12 Hz, and the mechanical coupling of the MCP joint, were conversely undermined consequent to the high exertion paradigm. The present study suggests that LA was most susceptible to muscle fatigue following sustained contraction at a lower exertion level, and diverging alternations among various physiological signals ascribed to exertion-dependent contributions of central and peripheral origins to muscle fatigue.

The Implementation of a Stand-alone Video Tracking and Analysis System for Animal Behavior Measurement in Morris Water Maze.

In this paper, a digital image tracking and analysis system based on FPGA is presented. The goal of this research is to build an animal tracking system with a new algorithm for Morris water maze experiment application. Our tracking algorithm can track animal motion and is insensitive to environment brightness change. The system can process the high-resolution image up to 700X480 pixels in real-time speed. We can analyze tiny animal behavior change precisely. This system is very compact and is portable. Compare with other similar device, our system is standalone operation without the necessary of a personal computer.

Fabrication optimisation of carbon fiber electrode with Taguchi method.

In this study, we describe an optimised procedure for fabricating carbon fiber electrodes using Taguchi quality engineering method (TQEM). The preliminary results show a S/N ratio improvement from 22 to 30 db (decibel). The optimised parameter was tested by using a glass micropipette (0.3 mm outer/2.5 mm inner length of carbon fiber) dipped into PBS solution under 2.9 V triangle-wave electrochemical processing for 15 s, followed by coating treatment of micropipette on 2.6 V DC for 45 s in 5% Nafion solution. It is thus shown that Taguchi process optimisation can improve cost, manufacture time and quality of carbon fiber electrodes.

The protective effect of dl-tetrahydropalmatine against the development of amygdala kindling seizures in rats.

The influence of dl-tetrahydropalmatine (THP), an active component isolated from a Chinese herbal medicine corydalis, was tested on the development of electrically kindled amygdala. The seizure activity was quantified by a ultrasonic system for vertical motion measurements. Intraperitoneal injection of THP (20 or 30 mg kg(-1)) 30 min before applying the daily kindling stimulus prevented the development of the kindling process. The behavioral seizure score and the motion responses which normally develop during electrical kindling were reduced below their initial values. The results suggest that THP is a very effective antiepileptogenic and anticonvulsant agent when applied to electrically kindled rats.