PubMed · 9560875
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
F Mai. Laterality in somatization.. https://doi.org/10.1097/00006842-199803000-00021
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The aim of the present study was to examine grip-load force regulation during unimanual and bimanual movements. Two protocols were included which manipulated the object's weight and covered distance. Results showed that grip-load ratio was adapted to the task requirements. During unimanual and bimanual symmetrical movements, an increased grip-load force ratio for long versus short amplitude movements as well as for light versus heavy weight movements was noted. These findings could be related to the observed movement speed variations associated with the tasks. During bimanual asymmetrical movements, the grip-load force ratio became comparable for both sides. When transporting different object's weights to constant distances, the grip-load force ratio of light weight movements decreased towards that of heavy weight movements. As movement speed was reduced, it indicates that grasping forces were adapted accordingly. When transporting constant object's weights to different distances, the grip-load force ratio of short amplitude movements increased towards that of long amplitude movements. Since movement speed was decreased, it suggests that a bimanual coordinative command overruled the automatic grip-load coupling. In conclusion, these data show that interlimb coupling induced a rescaling towards a common control structure, leading to similar grasping forces during bimanual movements with dissimilar actions.
This experiment investigates neonatal intersensory functioning between touch and vision for texture density. The experiment compared manual activity (holding time and hand pressure frequency) recorded on objects in the presence (test period) or absence of visual information (pre-test and post-test periods). Thirty-two babies were assigned to four experimental conditions according to texture density of the objects held and seen during the test period: Objects had either the same (matching conditions) or different (mismatching conditions) texture density information. The results clearly showed that in matching conditions, holding times were systematically increased during the test period. However, hand pressure frequency remained unchanged over the three test periods. In the mismatching conditions, holding times remained unchanged over the three test periods. However, hand pressure frequency systematically changed during the test period according to the texture density of the visual object. These results indicate newborns' capability to compare texture density information across modalities.
Two experiments examined the relationship between temporal pitch (and, more generally, rate) perception and auditory lateralization. Both used dichotic pulse trains that were filtered into the same high (3,900-5,400-Hz) frequency region in order to eliminate place-of-excitation cues. In experiment 1, a 1-s periodic pulse train of rate Fr was presented to one ear, and a pulse train of rate 2Fr was presented to the other. In the "synchronous" condition, every other pulse in the 2Fr train was simultaneous with a pulse in the opposite ear. In each trial, subjects concentrated on one of the two binaural images produced by this mixture: they matched its perceived location by adjusting the interaural level difference (ILD) of a bandpass noise, and its rate/pitch was then matched by adjusting the rate of a regular pulse train. The results showed that at low Fr (e.g., 2 Hz), subjects heard two pulse trains of rate Fr, one in the "higher rate" ear, and one in the middle of the head. At higher Fr (>25 Hz) subjects heard two pulse trains on opposite sides of the midline, with the image on the higher rate side having a higher pitch than that on the "lower rate" side. The results were compared to those in a control condition, in which the pulses in the two ears were asynchronous. This comparison revealed a duplex region at Fr > 25 Hz, where across-ear synchrony still affected the perceived locations of the pulse trains, but did not affect their pitches. Experiment 2 used a 1.4-s 200-Hz dichotic pulse train, whose first 0.7 s contained a constant interaural time difference (ITD), after which the sign of the ITD alternated between subsequent pulses. Subjects matched the location and then the pitch of the "new" sound that started halfway through the pulse train. The matched location became more lateralized with increasing ITD, but subjects always matched a pitch near 200 Hz, even though the rate of pulses sharing the new ITD was only 100 Hz. It is concluded from both experiments that temporal pitch perception is not driven by the output of binaural mechanisms.