Organization of voluntary movement.

There have recently been a number of advances in our knowledge of the organization of complex, multi-joint movements. Promising starts have been made in our understanding of how the motor system translates information about the location of external targets into motor commands encoded in a body-based coordinate system. Two simplifying strategies for trajectory control that are discussed are parallel specification of response features and the programming of equilibrium trajectories. New insights have also been gained into how neural systems process sensory information to plan and assist with task performance. A number of recent papers emphasize the feedforward use of sensory input, which is mediated through models of the external world, the body's physical plant, and the task structure. These models exert their influence at both reflex and higher levels and permit the preparation of predictive default parameters of trajectories as well as strategies for resolving task demands.     

Central and peripheral hemodynamic responses to passive limb movement: the role of arousal

The exact role of arousal in central and peripheral hemodynamic responses to passive limb movement in humans is unclear but has been proposed as a potential contributor. Thus, we used a human model with no lower limb afferent feedback to determine the role of arousal on the hemodynamic response to passive leg movement. In nine people with a spinal cord injury, we compared central and peripheral hemodynamic and ventilatory responses to one-leg passive knee extension with and without visual feedback (M+VF and M-VF, respectively) as well as in a third trial with no movement or visual feedback but the perception of movement (F). Ventilation (Ve), heart rate, stroke volume, cardiac output, mean arterial pressure, and leg blood flow (LBF) were evaluated during the three protocols. Ve increased rapidly from baseline in M+VF (55 ± 11%), M-VF (63 ± 13%), and F (48 ± 12%) trials. Central hemodynamics (heart rate, stroke volume, cardiac output, and mean arterial pressure) were unchanged in all trials. LBF increased from baseline by 126 ± 18 ml/min in the M+VF protocol and 109 ± 23 ml/min in the M-VF protocol but was unchanged in the F protocol. Therefore, with the use of model that is devoid of afferent feedback from the legs, the results of this study reveal that, although arousal is invoked by passive movement or the thought of passive movement, as evidenced by the increase in Ve, there is no central or peripheral hemodynamic impact of this increased neural activity. Additionally, this study revealed that a central hemodynamic response is not an obligatory component of movement-induced LBF.     

A model of plant-to-plant movement of aphids III. Studies of actual movement and apparent movement by simulation technique

The plant-to-plant movement of aphids was investigated by the simulation technique in this report. Trials satisfying the following conditions are repeated and the results are compared withShiyomi 's model (1967).

1. An arbitrary individual moves at any moment.
2. The individual moves straightly forward an arbitrary direction and climbs up the plant that he first encounters with.
3. There is no concentrative birth and death.

Some of the results are as follows:

1. For an ideal state of movement, an equation describing the relationship between the frequency of actual movement and the degree of changes in the spatial distribution by movement was obtained.
2. The actual movements, whose frequency we cannot count, changes the spatial distribution of insects, and this change can be evaluated by the changes of values of the parameters contained inShiyomi 's model. Using the statement (i), we can also estimate the frequency of movements of aphids in the ideal (extreme) state.

     

Post-establishment movement of western corn rootworm larvae (Coleoptera: Chrysomelidae) in Central Missouri corn

If registered, transgenic corn, Zea mays L., with corn rootworm resistance will offer a viable alternative to insecticides for managing Diabrotica spp. corn rootworms. Resistance management to maintain susceptibility is in the interest of growers, the Environmental Protection Agency, and industry, but little is known about many aspects of corn rootworm biology required for an effective resistance management program. The extent of larval movement by the western corn rootworm, Diabrotica virgifera virgifera LeConte, that occurs from plant-to-plant or row-to-row after initial establishment was evaluated in 1998 and 1999 in a Central Missouri cornfield. Post-establishment movement by western corn rootworm larvae was clearly documented in two of four treatment combinations in 1999 where larvae moved up to three plants down the row and across a 0.46-m row. Larvae did not significantly cross a 0.91-m row after initial host establishment in 1998 or 1999, whether or not the soil had been compacted by a tractor and planter. In the current experiment, western corn rootworm larvae moved from highly damaged, infested plants to nearby plants with little to no previous root damage. Our data do not provide significant insight into how larvae might disperse after initial establishment when all plants in an area are heavily damaged or when only moderate damage occurs on an infested plant. A similar situation might also occur if a seed mixture of transgenic and isoline plants were used and if transgenic plants with rootworm resistance are not repellent to corn rootworm larvae.     

Central mechanisms of fever.

The possible role of various potential chemical mediators in the production of fever is reviewed. A major problem in this field is the very considerable conflict of evidence, let alone interpretation. On the existing evidence, it appears unlikely that monoamines, acetyl choline, or alterations in relative concentrations of sodium and calcium play any major role in the production of fever. Recent evidence makes it unlikely that prostaglandins have a direct role in this mechanism, though the involvement of other metabolites of arachidonic acid has not been excluded. It is possible that protein synthesis may play a part in the central action of leukocyte pyrogen.     

Ultrasonic monitoring of fetal respiratory movement.

Ultrasonic monitoring of fetal respiratory movement including velocity measurements is described. Both proximal and distal walls of the fetal chest are imaged simultaneously. The time-position mode clearly defines fetal respiratory movement and rejects artefacts.     

Dr Samuel Johnson's movement disorder.

Dr Samuel Johnson was noted by his friends to have almost constant tics and gesticulations, which startled those who met him for the first time. He also made noises and whistling sounds; he made repeated sounds and words and irregular or blowing respiratory noises. Further, he often carried out pronounced compulsive acts, such as touching posts, measuring his footsteps on leaving a room, and performing peculiar complex gestures and steps before crossing a threshold. His symptoms of (a) involuntary muscle jerking movements and complex motor acts, (b) involuntary vocalisation, and (c) compulsive actions constitute the symptom complex of Gilles de la Tourette syndrome (Tourette''s syndrome), from which Johnson suffered most of his life. This syndrome is of increasing interest recently because it responds to haloperidol, and because there are new insights into a possible biochemical basis for the tics, vocalisations, and compulsions.