Similarities between explicit and implicit motor imagery in mental rotation of hands: an EEG study

Chronometric and imaging studies have shown that motor imagery is used implicitly during mental rotation tasks in which subjects for example judge the laterality of human hand pictures at various orientations. Since explicit motor imagery is known to activate the sensorimotor areas of the cortex, mental rotation is expected to do similar if it involves a form of motor imagery. So far, functional magnetic resonance imaging and positron emission tomography have been used to study mental rotation and less attention has been paid to electroencephalogram (EEG) which offers a high time-frequency resolution. The time-frequency analysis is an established method for studying explicit motor imagery. Although hand mental rotation is claimed to involve motor imagery, the time-frequency characteristics of mental rotation have never been compared with those of explicit motor imagery. In this study, time-frequency responses of EEG recorded during explicit motor imagery and during a mental rotation task, inducing implicit motor imagery, were compared. Fifteen right-handed healthy volunteers performed motor imagery of hands in one condition and hand laterality judgement tasks in another while EEG of the whole head was recorded. The hand laterality judgement was the mental rotation task used to induce implicit motor imagery. The time-frequency analysis and sLORETA localisation of the EEG showed that the activities in the sensorimotor areas had similar spatial and time-frequency characteristics in explicit motor imagery and implicit motor imagery conditions. Furthermore this sensorimotor activity was different for the left and for the right hand in both explicit and implicit motor imagery. This result supports that motor imagery is used during mental rotation and that it can be detected and studied with EEG technology. This result should encourage the use of mental rotation of body parts in rehabilitation programmes in a similar manner as motor imagery

The influence of water stress (drought) on the mineral and vitamin potential of the leaves of Ocimum gratissimum (L).

The influence of water stress (drought) on the mineral and vitamin potential of the leaves of Ocimum gratissimum was investigated. Cultivated O. gratissimum plants grown in plastic planting buckets were subjected to mild water stress by irrigating each planting bucket with 500 ml of water once in a week. On the other hand, in the control treatment, each planting bucket was irrigated with 750 ml of water three times in a week. Treatment commenced two months after seed emergence. The leaves of the plants were harvested one month later for analysis. Results obtained indicated that water stress (drought), significantly (

Is implicit motor imagery a reliable strategy for a brain computer interface?

Explicit motor imagery (eMI) is a widely used brain computer interface (BCI) paradigm, but not everybody can accomplish this task. Here we propose a BCI based on implicit motor imagery (iMI). We compared classification accuracy between eMI and iMI of hands. Fifteen able bodied people were asked to judge the laterality of hand images presented on a computer screen in a lateral or medial orientation. This judgement task is known to require mental rotation of a person’s own hands which in turn is thought to involve iMI. The subjects were also asked to perform eMI of the hands. Their electroencephalography (EEG) was recorded. Linear classifiers were designed based on common spatial patterns. For discrimination between left and right hand the classifier achieved maximum of 81 ± 8% accuracy for eMI and 83 ± 3% for iMI. These results show that iMI can be used to achieve similar classification accuracy as eMI. Additional classification was performed between iMI in medial and lateral orientations of a single hand; the classifier achieved 81 ± 7% for the left and 78 ± 7% for the right hand which indicate distinctive spatial patterns of cortical activity for iMI of a single hand in different directions. These results suggest that a special brain computer interface based on iMI may be constructed, for people who cannot perform explicit imagination, for rehabilitation of movement or for treatment of bodily spatial neglect

Polyhedral charge-packing model for blood pH changes in disease states

This work is the extension to an earlier report of a model, which explained the normal blood pH of 7.4 in terms of the octahedral packing of the six hydroxyl, OH-, ions to one hydrogen, H+, ion that exist atthat pH, as this would be the most, naturally, stable arrangement. The logical, possible shifts from the octahedral ideal are suggested to be to the next most stable and efficient natural structures, the otherregular polyhedra (tetrahedron, cube, dodecahedron and the icosahedron), depending on the hydroxyl to proton ratio available. Polyhedral charge-structuring is suggested to help define a ‘polyhedralcharge-packing pH zone’ (From pH = 7.30, for tetrahedral, to pH = 7.65 for dodecahedral packing), which lies in the neighborhood of the well known physiological pH range. Literature is cited in support of pH7.65 as the extreme upper limit of tolerable alkalosis. Experimental results from studies on two acidotic diseases (Sickle cell disease, pH = 7.32 ± 0.08 and Asthma, pH = 7.29 ± 0.03) are presented as evidenceof the tetrahedron-based tolerable, stable, low limit pH in acidosis. Some medical implications of these ideas are discussed. For instance, the model suggests that the generalized definition of metabolicacidosis as pH less than 7.3 (pH < 7.3) is informed by the underlying tetrahedral charge-packing structure at this pH, which would collapse immediately the blood pH falls below this critical threshold

Influence of motor imagination on cortical activation during functional electrical stimulation

&lt;b&gt;Objective&lt;/b&gt; Motor Imagination (MI) and Functional Electrical Stimulation (FES) can activate the sensory-motor cortexthrough efferent and afferent pathways respectively. Motor Imagination can be used as a control strategy to activate FES through a Brain-computer interface as the part of a rehabilitation therapy. It is believed that precise timing between the onset of MI and FES is important for strengthening the cortico-spinal pathways but it is not known whether prolonged MI during FES influences cortical response.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; Electroencephalogram was measured in ten able-bodied participants using MI strategy to control FES through a BCI system. Event related synchronisation/desynchronisation (ERS/ERD) over the sensory-motor cortex was analysed and compared in three paradigms: MI before FES, MI before and during FES and FES alone activated automatically.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt; MI practiced both before and during FES produced strongest ERD. When MI only preceded FES it resulted in a weaker beta ERD during FES than when FES was activated automatically. Following termination of FES, beta ERD returns to the baseline level within 0.5 s while alpha ERD took longer than 1 s.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt; When MI and FES are combined for rehabilitation purposes it is recommended that MI is practiced throughout FES activation period.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Significance&lt;/b&gt; The study is relevant for neurorehabilitation of movement.&lt;p&gt;&lt;/p&gt

Green Marketing: Conceptualizations, Managerial Practices, Challenges and Research Agenda

Green marketing has attracted some attention in recent times. The general interests in green marketing have been as a result of the increased concerns related to the inefficient use of resources, the poor management of wastes, the high use of fossil fuels, the increase in the emission of greenhouse gases, in addition to relevant pressures from consumers, clients, civil society organizations and governments, among others. Green marketing is an important strand of green business, which is concerned with reducing the impact of business practices on elements of the environment. It, specifically, focuses on reducing the   adverse impact of marketing practices on the environment via such traditional marketing activities as product designing, producing product, product packaging, product labelling, product promotion, product distribution, and consuming goods and services that are friendly to the environment. It entails certain broad marketing issues such as product planning, processing, production, promotion, distribution, in addition to protective interest in people, society and planet which are designed by an organization to show its objective of reducing the adverse effect on the environment of its marketing activities. This paper conceptualizes the green marketing construct, presents some of its practices and challenges, and suggests research direction (with a research instrument) for investigating the construct in different organizational and environmental settings

The energy cost of kidney proton dialysis in sickle cell anaemia

The acidosis known to be associated with sickle cell anaemia is exploited in this work to estimate its energy cost to the kidney that has to dialyse the excess protons from the blood into urine against aconcentration gradient, thereby doing significant extra work. The mean blood and urine pHs measured for the four discrete sickle cell states (42 subjects with approximately equal numbers of males andfemales per group, to minimise sex bias) are: HbAA = 7.39 ± 0.07 and 6.54 ± 0.15, HbAS = 7.35 ± 0.09 and 6.44 ± 0. 15, HbSS = 7.32 ± 0.08 and 5.89 ± 0. 39, HbSS-crisis = 7.15 ± 0.12 and 4.75 ± 0.46, respectively. From these data, the estimated enthalpies of dialysis, DHd, for each of the four states are: HbAA = 1.96RT 4.94 kJ, HbAS = 2.10RT 5.29 kJ, HbSS =3.29RT 8.29 kJ, and HbSS-crisis = 5.53RT 13.93 kJ. The estimated entropies of dialysis, TDSd, compared to the normal HbAA state are: HbAA = 0.00RT 0.00 kJ;HbAS = 0.14RT 0.35 kJ, HbSS = 1.34RT 3.38 kJ and HbSS-crisis = 3.57RT 8.99 kJ (R = 8.31J-mol-1 K-1and T = 303K). The conclusion from this work is that sickle cell disease is very energy costly to the kidney as most of the energy for proton dialysis is wasted as a result of high entropy

Speed Related Defect Detection in a Seta 4-Ball Life Testing Machine

Many rotating machines operate over a range of speeds. It is therefore of practical interest in machine condition monitoring to see if there is a relationship between the speed at which diagnostic inspection is carried out and the early detection of incipient defect in the machine. In this paper, the effect of operating speed in the early detection of incipient defect in a Seta mechanism is investigated using a number of techniques. It is shown that for-an analysis bandwidth optimum for incipient defect detection, the detection sensitivity is improved if the diagnostic inspection of the mechanism is carried out at lower rather than higher speeds

A Simple K-Map Based Variable Selection Scheme in the Direct Synthesis of Logic Functions with Multiplexers

A multiplexer with (n-l) data select inputs can realise directly a function of n variables. In this paper, a simple k-map based variable selection scheme is proposed such that an n variable logic function can be synthesised using a multiplexer with (n-q) data input variables and q data select variables. The procedure is based on the fact that if 2X minterms (where x = 1, 2, 3) from a minterm list are adjacent on a k-map, the minimised function read from the map contains information on the variable or variables which form the map highest number of l-cubes. 2-cubes or 3-cubes of the function. Such variables have the lowest frequency of occurrence in the minimised function. The criterion for eliminating (n-q) variables from the data select input is to choose (n-q) variables with the lowest frequencies of occurrence in the minimised function and use them as the data input variables of the multiplexer. The data input values of the multiplexer are obtained by constructing a MEV -map using the (n-q) variables as map entered variables and the q data select variables as mapping variables. The procedure is illustrated with examples

Problems of Software Detection of Periodic Features in a Time Series for Diagnosis

Problems arise when attempts are made to extract automatically, visually obvious periodic features indicative of defects in a vibration time series for diagnosis using computers. Such problems may be interpretational in nature arising either from insufficient knowledge of the mechanism, or the convolution of the source signal with the system structure effect. Some of the periodic structures may turn out to be interferences originating from the cyclic nature of events taking place in the mechanism. Such periodic interferences complicate considerably the selection of suitable parameter values to be used in the period extracting algorithms. There is also the problem of deciding which of the multiple peaks or nulls resulting from impact instabilities in the time series is the true peak or null to be used in estimating the impact period. These problems must be solved if the extracted period is to be used successfully for source identification of defective components. In this paper, we present the ways we have developed to addressing these problem