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There is some discrepancy over the extent to which reflex pathways from different cutaneous nerves in the hand and foot link the cervical and lumbar spinal cord in neurologically intact humans. The present experiments were designed to determine whether stimulation of a cutaneous nerve in the foot or in the hand evoked reflexes in the non-stimulated limbs(More)
Quick voluntary responses to environmental stimuli are required of people on a daily basis. These movements have long been thought to be controlled via cortical loops involving processing of the stimulus and generation of a suitable response. Recent experiments have shown that in simple reaction time (RT) tasks, the appropriate response can be elicited much(More)
A startle stimulus has been shown to elicit a ballistic response in a reaction time (RT) task at very short latencies without involvement of the cerebral cortex (J. Valls-Sole, J. C. Rothwell, F. Gooulard, G. Cossu, & E. Munoz, 1999). The present authors examined the nature of the startle response. A simple RT task was used in which 8 participants performed(More)
In 1899, R. S. Woodworth published a seminal monograph, "The Accuracy of Voluntary Movement." As well as making a number of important empirical contributions, Woodworth presented a model of speed-accuracy relations in the control of upper limb movements. The model has come to be known as the two-component model because the control of speeded limb movements(More)
Reflexes undergo modulation according to task and timing during standing, walking, running, and leg cycling in humans. Both cutaneous and Hoffman (H-) reflexes are modulated by movement and task. However, recent evidence suggests that the modulation pattern for cutaneous and H-reflexes may be different. We sought to clarify this issue by reducing the effect(More)
Recent experiments pairing a startling stimulus with a simple reaction time (RT) task have shown that when participants are startled, a prepared movement was initiated earlier in comparison to voluntary initiation. It has been argued that the startle acts to trigger the response involuntarily. However, an alternative explanation is that the decrease in RT(More)
Vision plays an important role in the planning and execution of target-directed aiming movements. In this review, we highlight the limitations that exist in detecting visual regulation of limb trajectories from traditional kinematic analyses such as the identification of discontinuities in velocity and acceleration. Alternative kinematic analyses that(More)
Human vision allows us both to perceive our surroundings (e.g., identify a cup) and to interact with them (e.g., reach for a cup). It is generally accepted that these functions are supported by a ventral system for conscious object identification and a dorsal system for unconscious control of action, but little research has addressed the extent to which(More)
Two experiments were conducted in which participants (N = 12, Experiment 1; N = 12, Experiment 2) performed rapid aiming movements with and without visual feedback under blocked, random, and alternating feedback schedules. Prior knowledge of whether vision would be available had a significant impact on the strategies that participants adopted. When they(More)
Recent studies have used a loud (> 120 dB) startle-eliciting acoustic stimulus as a probe to investigate early motor response preparation in humans. The use of a startle in these studies has provided insight into not only the neurophysiological substrates underlying motor preparation, but also into the behavioural response strategies associated with(More)