Jennifer A. Stevens

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Four experiments were completed to characterize the utilization of visual imagery and motor imagery during the mental representation of human action. In Experiment 1, movement time functions for a motor imagery human locomotion task conformed to a speed-accuracy trade-off similar to Fitts' Law, whereas those for a visual imagery object motion task did not.(More)
Three experiments assessed the influence of the Ebbinghaus illusion on size judgments that preceded verbal, grasp, or touch responses. Prior studies have found reduced effects of the illusion for the grip-scaling component of grasping, and these findings are commonly interpreted as evidence that different visual systems are employed for perceptual judgment(More)
It is widely accepted that human motor control is anticipatory in nature. Previous studies have used electromyography (EMG) to examine muscle responses to falling objects and identified anticipatory muscle tensing (AMT) as a spike in activation that occurs prior to object impact. Some studies have suggested that humans use an internal model of gravity to(More)
Motor imagery (MI) is widely used to study cognitive aspects of the neural control of action. Prior studies were mostly centred on hand and arm movements. Recently a few studies have used imagery tasks to explore the neurophysiology of human gait, but it remains unclear how to ascertain whether subjects actually perform imagery of gait as requested. Here we(More)
Prior studies have suggested that visually guided actions are resistant to the effects of some pictorial size illusions, e.g., the maximum grip aperture component of a grasp for an element of the Ebbinghaus illusion display. We present evidence that when participants prepare to grasp, the reduction in illusion magnitude observed for action components is(More)
The embodied cognition perspective has provided a formalization of the idea that the motor state is a characteristic of being that permeates all of human processing. We review this perspective and experimental evidence supporting its claim. It is further considered that the motor behaving human moves within various spaces, each affording different actions.(More)
Proprioception is the sense of the position of one's own body. Here, we present a case study of an individual with proprioceptive loss in one limb consequent to stroke. The patient indicated that merely touching his impaired arm with his unimpaired arm temporarily restored his proprioception. We examined this claim and the effects of imagined touch by the(More)
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