Visual Field Left Hemisphere Advantage Research Articles

Hemispheric asymmetries of a motor memory in a recognition test after learning a movement sequence

Two experiments utilizing a spatial-temporal movement sequence were designed to determine if the memory of the sequence is lateralized in the left or right hemisphere. In Experiment 1, dominant right-handers were randomly assigned to one of two acquisition groups: a left-hand starter and a right-hand starter group. After an acquisition phase, reaction time (RT) was measured in a recognition test by providing the learned sequential pattern in the left or right visual half-field for 150ms. In a retention test and two transfer tests the dominant coordinate system for sequence production was evaluated. In Experiment 2 dominant left-handers and dominant right-handers had to acquire the sequence with their dominant limb. The results of Experiment 1 indicated that RT was significantly shorter when the acquired sequence was provided in the right visual field during the recognition test. The same results occurred in Experiment 2 for dominant right-handers and left-handers. These results indicated a right visual field left hemisphere advantage in the recognition test for the practiced stimulus for dominant left and right-handers, when the task was practiced with the dominant limb.

Cerebral asymmetries in inspection time?

Recent studies have suggested that there are low-level processing asymmetries across the cerebral hemispheres, with a right visual field-left hemisphere advantage in tasks involving temporal resolution. In the present report, one such task, inspection time, was measured separately for each cerebral hemisphere in 10 right-handed male subjects over 5 days. A number of methodological improvements were made on previous studies in which a general right visual field-left hemisphere advantage had been found relative to the left visual field-right hemisphere in inspection time performance. The present results suggest that there is no general left hemisphere advantage in inspection time, although there might be asymmetries in practice effects across the hemispheres. The findings also suggest the existence of individual differences in the extent and direction of hemispheric specialisation for this task (ranging from left hemisphere dominance to marked right hemisphere dominance for some subjects) even in right-handed subjects.

Neurophysiological and MRI assessment in demyelinating optic neuritis

Two experiments utilizing a spatial-temporal movement sequence were designed to determine if the memory of the sequence is lateralized in the left or right hemisphere. In Experiment 1, dominant right-handers were randomly assigned to one of two acquisition groups: a left-hand starter and a right-hand starter group. After an acquisition phase, reaction time (RT) was measured in a recognition test by providing the learned sequential pattern in the left or right visual half-field for 150 ms. In a retention test and two transfer tests the dominant coordinate system for sequence production was evaluated. In Experiment 2 dominant left-handers and dominant right-handers had to acquire the sequence with their dominant limb. The results of Experiment 1 indicated that RT was significantly shorter when the acquired sequence was provided in the right visual field during the recognition test. The same results occurred in Experiment 2 for dominant right-handers and left-handers. These results indicated a right visual field left hemisphere advantage in the recognition test for the practiced stimulus for dominant left and right-handers, when the task was practiced with the dominant limb.

Hemispheric asymmetry in the processing of absolute versus relative spatial frequency

Observers indicated whether a stimulus presented to one visual field or the other consisted of two sine-wave gratings (the baseline stimulus) or those same two gratings with the addition of a 2 cycle per degree (cpd) component. When the absolute spatial frequencies of the baseline stimulus were low (0.5 and 1.0 cpd), there was a left visual field-right hemisphere (LVF-RH) advantage in reaction time (RT) to respond to the baseline stimulus which disappeared when the 2 cpd component was added (i.e., the stimulus consisted of 0.5, 1.0, and 2.0 cpd components). When the absolute spatial frequencies of the baseline stimulus were moderate to high (4.0 and 8.0 cpd), a right visual field-left hemisphere advantage in RT to respond to the baseline stimulus approached significance and shifted to a significant LVF-RH advantage when the 2 cpd component was added (i.e., the stimulus consisted of 2.0, 4.0, and 8.0 cpd components. That is, adding the same 2 cpd component caused opposite shifts in visual laterality depending on whether 2 cpd was a relatively high or relatively low frequency compared to the baseline.

Lateral asymmetries in the naming of words and corresponding line drawings

Laterally displaced line drawings and the words which name these drawings were tachistoscopically presented to adult subjects. For words, as expected, a right visual field-left hemisphere advantage was obtained. For line drawings, in contrast to previous studies which have typically reported a right visual field-left hemisphere advantage, no visual field asymmetry was found. The absence of a visual field asymmetry for line drawings is consistent with reports of a shift toward greater right hemisphere involvement in the recognition of pictographic as compared to phonetic writing systems and concrete/imageable words as compared to abstract/nonimageable words. Further, the present results seem consistent with findings on picture recognition and naming abilities in brain-damaged patients.

Hemispheric differences in recognition memory for letters

An experiment was conducted to examine the relationship between hemisphere specialization and temporal changes in the status of visual and verbal codes in short-term memory. The procedure, which involved presentation of a single target letter in central vision followed by a unilateral probe, yielded a general right visual field left-hemisphere advantage for physical and name matches at stimulus onset asynchronies greater than.05 sec. The results support the hemisphere-priming view advanced by Kinsbourne (1973) and are inconsistent with alternative accounts involving temporal changes in representations in the cerebral hemispheres.