Showing papers on "Motor imagery published in 1989"

Regional cerebral blood flow patterns in visual imagery.

Abstract: Regional cerebral blood flow patterns were investigated by means of single photon emission computerized tomography in subjects who solved cognitive tasks which either did or did not require the use of visual imagery. In a first experiment judging the correctness of visual imagery sentences like "a grapefruit is bigger than an orange" led to increases of regional activity in inferior temporal and in the left inferior-occipital region when compared to blood flow patterns elicited by judgements about low imagery sentences or by responding differentially to "yes" and "no". Motor imagery sentences did not cause such an increase. In a second experiment a condition in which visual images were used for counting the corners of letters was compared to a condition in which subjects internally rehearsed the alphabet. The only difference concerned the inferior frontal regions which showed higher activity in rehearsing the alphabet. However, activity in inferior temporal and inferior occipital regions showed a positive correlation to the self-rated vividness of the visual images in the corner counting condition. The results of both experiments yield converging evidence that visual imagery is selectively related to activity of inferior-temporal and occipital regions. They thus support the hypothesis that the cerebral correlate of visual imagery is different from that of non-imaginal thinking.

A Motor Learning Model for Stroke Rehabilitation

Abstract: Summary The emergence of research findings in the area of movement science enables us to have a better understanding of human movement, its control and dyscontrol. This should provide impetus for improved analysis of motor performance in the clinic and for the development of new rehabilitation strategies. This paper illustrates the process by which movement-related scientific findings can be utilised practically in the rehabilitation of individuals following stroke. Emphasis is therefore on the analysis and training of specific tasks (such as standing up, walking, reaching for an object), utilising information about the biomechanical characteristics of each task, muscle function and physiology, motor learning and motor control processes.

Noninvasive Functional Investigations into Human Cortical Motor Physiology, Motor Learning, and Motor Imagery

Abstract: In humans, registration of regional cerebral blood flow (rCBF) and electrophysiological recordings offer the possibility to (a) study directly parameters of brain activity and (b) establish functional-anatomical relations in behavioral tasks. Current trends in imaging of brain functions include the use of scalp-recorded negative DC potential shifts which are time-locked to the performance of cognitive or motor tasks. A reason for utilizing this phenomenon is the notion of the physiological significance of DC potential shifts as recordable from the scalp surface; it has clearly been established that excitatory synaptic currents of cortical neurons generate electrical dipoles that are negative on the surface and positive at depth. The spatial resolution of scalp-recorded DC potential shifts is limited but is, for example, sufficient for separating neuronal activity of circumscribed cortical areas involved in the execution of movements of different parts of the body (Boschert and Deecke 1986). Spatial transformations of EEG recordings (e.g., Laplacian) can offer additional possibilities for estimating current sources contributing to surface-recorded electrical shifts and may help to distinguish different sources underlying these shifts.