Effects of three levels of arousal on 3-back working memory task performance.

This study investigated how three levels of arousal affected performance of a 3-back working memory task. Ten female and ten male university students participated in this experiment. With pictures selected from a group test, three levels of arousal were induced--i.e., tense, neutral, and relaxed emotions. Each subject was run through the procedure three times, once for each arousal level. The procedure consisted of six phases for each arousal condition: (1) Rest 1 (2 min), (2) Picture 1 (presenting emotion arousing photos for 2 min), (3) 3-back working memory task 1 (2 min), (4) Picture 2 (presenting emotion-arousing photos for 2 min), (5) 3-back working memory task 2 (2 min), and (6) Rest 2 (2 min). The skin conductance level of electrodermal activity was also measured during all phases of the experiment. The accuracy rate of 3-back working memory task performance was the highest at a neutral emotional state, followed by relaxed and then tense emotional states. There were no significant differences in reaction time.

Changes in simple visual matching task performance and physiological signals in intellectually and developmentally disabled people due to administration of highly concentrated oxygen.

BACKGROUND: This study attempted to identify the effect of administration of highly concentrated oxygen on simple visual matching task performance, blood oxygen saturation [SpO2 (%)], and heart rate [HR (bpm)] of intellectually and developmentally disabled people. METHODS: Nineteen intellectually and developmentally disabled people (mean age 30.6 ± 5.7 years) participated in an experiment consisting of a simple visual matching task performed under 21% and 92% oxygen. SpO2 and HR were measured under both oxygen conditions. RESULTS: When 92% oxygen was supplied, the response time decreased, SpO2 increased, and HR decreased compared to the vales obtained using 21% oxygen. The response time decreased for subjects with a high SpO2 and HR during the simple visual matching task phase. CONCLUSION: This result supports the hypothesis that administration of highly concentrated oxygen can positively affect the cognitive performance of intellectually and developmentally disabled people.

Development of a tactile stimulator with simultaneous visual and auditory stimulation using E-Prime software.

In this study, a tactile stimulator was developed, which can stimulate visual and auditory senses simultaneously by using the E-Prime software. This study tried to compensate for systematic stimulation control and other problems that occurred with previously developed tactile stimulators. The newly developed system consists of three units: a control unit, a drive unit and a vibrator. Since the developed system is a small, lightweight, simple structure with low electrical consumption, a maximum of 35 stimulation channels and various visual and auditory stimulation combinations without delay time, the previous systematic problem is corrected in this study. The system was designed to stimulate any part of the body including the fingers. Since the developed tactile stimulator used E-Prime software, which is widely used in the study of visual and auditory senses, the stimulator is expected to be highly practical due to a diverse combination of stimuli, such as tactile-visual, tactile-auditory, visual-auditory and tactile-visual-auditory stimulation.

Changes of 2-back task performance and physiological signals in ADHD children due to transient increase in oxygen level.

This study investigated the effect of 92% oxygen administration on 2-back task performance, blood oxygen saturation (SpO(2) [%]), and heart rate (HR [bpm]) of Attention Deficit Hyperactivity Disorder (ADHD) children. Subjects were thirteen boys (mean 12.9±1.3 years) who were diagnosed as ADHD and are under treatment, having no disease or abnormality in a respiratory system or a periphery vascular flow system. The experiment consisted of two runs: one was a 2-back task under normal air (21% oxygen) condition and the other under hyperoxic air (92% oxygen) condition. The experiment sequence in each run consisted of three phases, which included the Adaptation phase (1 min) after oxygen administration, the Control phase (2 min) that maintained a stable condition before the task, and the Task phase (2 min) that performed 2-back task. SpO(2) and HR were measured during each phase. The analysis of cognitive performance with 92% oxygen administration when compared to 21% oxygen revealed that the response time decreased. When 92% oxygen in the air was supplied, the blood oxygen saturation increased while the heart rate decreased compared to those under the 21% oxygen condition. The response time also decreased for the subjects with a high SpO(2) during the Task phase. This showed that due to sufficient oxygen supply necessary for cognitive processing, SpO(2) increased and heart rate decreased. Therefore, an increase in cognitive ability such as a decrease in response time was observed in a transient period for ADHD children.

A study on orbital volume of Korean people in their 20s or 40s.

AIMS: To measure the orbital volume of normal Korean people in two different age groups (subjects were in their 20s or 40s), and analyze the differences of orbital volume with respect to age and gender. In addition, to analyze correlation between body parameters (height and weight) and the orbital volume. METHODS: Magnetic resonance imaging (MRI) data were acquired for a total of 143 subjects, consisting of 71 subjects in their 20s (32 males and 39 females) and 72 subjects in their 40s (30 males and 42 females). Two-way ANOVA was used to analyze how orbital volume changes with respect to gender and age. A multiple regression analysis was performed to investigate the correlation between body parameters and the orbital volume. RESULTS: The orbital volume of subjects in their 20s was larger than that of subjects in their 40s, and the volume was larger in men than in women. As age increased, the decrease in the orbital volume of women was greater than that of men. While weight and height showed positive correlations with orbital volume in male and female subjects in their 20s, respectively, weight showed a positive correlation with orbital volume in male and female subjects in their 40s. CONCLUSIONS: These results provide basic information about the effect of age, gender, and body parameters on orbital volume of Korean people in their 20s or 40s.

Effects of gender and age on anterior commissure volume.

The purpose of this study was to measure the average anterior commissure (AC) volume of normal subjects in their 20s or 40s and to determine the effects of gender and age on AC volume. Magnetic resonance brain images were obtained for 93 people in their 20s (46 men, 47 women) and 87 in their 40s (36 men, 51 women). To investigate the effect of gender and age on AC volume, two-way analysis of variance, which used gender (two levels) and age (two levels) as independent variables, was employed. For subjects in their 20s, there was no difference in AC volume between genders, but for those in their 40s, the AC volume of males was less than that of females. There was no difference in AC volume between females in their 20s or 40s; however, the AC volume of men in their 40s was less than that for those in their 20s. There were gender-influenced differences in AC volume changes related to aging.

A simple 5-DoF MR-compatible motion signal measurement system.

The purpose of this study was to develop a simple motion measurement system with magnetic resonance (MR) compatibility and safety. The motion measurement system proposed here can measure 5-DoF motion signals without deteriorating the MR images, and it has no effect on the intense and homogeneous main magnetic field, the temporal-gradient magnetic field (which varies rapidly with time), the transceiver radio frequency (RF) coil, and the RF pulse during MR data acquisition. A three-axis accelerometer and a two-axis gyroscope were used to measure 5-DoF motion signals, and Velcro was used to attach a sensor module to a finger or wrist. To minimize the interference between the MR imaging system and the motion measurement system, nonmagnetic materials were used for all electric circuit components in an MR shield room. To remove the effect of RF pulse, an amplifier, modulation circuit, and power supply were located in a shielded case, which was made of copper and aluminum. The motion signal was modulated to an optic signal using pulse width modulation, and the modulated optic signal was transmitted outside the MR shield room using a high-intensity light-emitting diode and an optic cable. The motion signal was recorded on a PC by demodulating the transmitted optic signal into an electric signal. Various kinematic variables, such as angle, acceleration, velocity, and jerk, can be measured or calculated by using the motion measurement system developed here. This system also enables motion tracking by extracting the position information from the motion signals. It was verified that MR images and motion signals could reliably be measured simultaneously.