No abstract

Introduction A cost-effective myoelectric prosthetic hand for persons with wrist amputations is a need for developing countries. Instead of trying to develop manipulation of all the fingers, which would be complex, expensive, and demanding on battery power, we took an approach to make the design simple but moderately usable. Methods and Materials Because a sizable number of tasks can be done by controlling the thumb only, we anticipate that it would be an efficient design where the user will control only the thumb using electromyographic (EMG) signals. The shape of the hand is such that it will let the user hold small objects, such as a pen. A mannequin's hand was used as the structure, and after specific modification, the necessary circuitry was set up. Surface electrodes were used to acquire the EMG signals, which were then amplified using a bioelectric amplifier specifically designed and developed for this purpose. A microcontroller-based interface detects EMG and controls the DC gear motor that moves the thumb. Results The thumb of the developed unit responded to contraction of the arm muscles as desired. The user can control the thumb using his or her EMG signal and write holding a pen. A box-and-blocks test was conducted in which, on average, the user was able to move 6.6 blocks per minute. Conclusions The design is moderately usable but needs some minor improvements before practical use.

Mirror Neurons (MNs) respond similarly when primates make or observe grasping movements. Recent work indicates that reward expectation influences rostral M1 (rM1) during manual, observational, and Brain Machine Interface (BMI) reaching movements. Previous work showed MNs are modulated by subjective value. Here we expand on the above work utilizing two non-human primates (NHPs), one male Macaca Radiata (NHP S) and one female Macaca Mulatta (NHP P), that were trained to perform a cued reward level isometric grip-force task, where the NHPs had to apply visually cued grip-force to move and transport a virtual object. We found a population of (S1 area 1–2, rM1, PMd, PMv) units that significantly represented grip-force during manual and observational trials. We found the neural representation of visually cued force was similar during observational trials and manual trials for the same units; however, the representation was weaker during observational trials. Comparing changes in neural time lags between manual and observational tasks indicated that a subpopulation fit the standard MN definition of observational neural activity lagging the visual information. Neural activity in (S1 areas 1–2, rM1, PMd, PMv) significantly represented force and reward expectation. In summary, we present results indicating that sensorimotor cortices have MNs for visually cued force and value.

Mirror Neurons (MN) respond similarly when primates make, or observe, grasping movements. Recent work indicates that reward expectation influences M1 during manual, observational, and Brain Machine Interface (BMI) reaching movements. Previous work showed MN are modulated by subjective value. Here we expand on the above work utilizing two non-human primates (NHPs), one male Macaca Radiata (NHP S) and one female Macaca Mulatta (NHP P), that were trained to perform a cued reward level isometric grip force task, where the NHPs had to apply visually cued grip force to move and transport a virtual object. We found a population of (S1, M1, PMd, PMv) units that significantly represented grip force during manual and observational trials. We found the neural representation of visually cued force was similar during observational trials and manual trials for the same units, however, the representation was weaker during observational trials. Comparing changes in neural time lags between manual and observational tasks indicated that a subpopulation fit the standard MN definition of observational neural activity lagging the visual information. Neural activity in (S1, M1, PMd, PMv) significantly represented force and reward expectation. In summary, we present results indicating that sensorimotor cortices have MN for visually cued force and value.

Anaemia is a common disorder in which the percentage of haemoglobin in a person's blood decreases below a certain level. Sometimes in medical emergency, it is necessary to know the percentage of haemoglobin of a patient and it is usually done by laboratory testing of blood drawn from a vein, which is semi-invasive and time consuming. Doctors can make a quick approximate assessment from the redness of the inner lower eyelid, but it is not quantitative. However, it suggests that quantitative values may be obtained analyzing an optical image of the same, and was the aim of the present work. As a preliminary study, images of inner lower eyelids of 7 persons were obtained using two digital cameras (Nikon DSLR and Nokia phone) under a fixed lighting condition and the haemoglobin counts in their blood were obtained using standard blood tests. Using software developed for this work, several regions of size 10x10 pixels were manually chosen to avoid areas giving strong reflections of the incident light and the average red pixel values for all of these regions were determined. These values were plotted against the percentage of haemoglobin for the two cameras separately. Both the graphs showed similar behavior and respective linear trend lines were fitted to each which gave good correlations, the coefficients being 0.83 and 0.81 respectively. The green and blue pixel values did not give any reasonable trend and so were not studied further. If other variables, such as lighting and camera exposure can be kept fixed, it may be possible to improve the accuracy further.