Biomedical subjects

C Michimata

Publications and source records attributed to C Michimata.

3 recordsLinked to original sources

PubMed1989

Categorization versus distance: hemispheric differences for processing spatial information.

It has been hypothesized that the brain computes two different kinds of spatial-relation representations: one used to assign a spatial relation to a category and the other used to specify metric distance with precision. The present visual half-field experiment offers support for this distinction by showing that the left and right cerebral hemispheres make more effective use of the categorization and metric distance representations, respectively. Furthermore, the inclusion of a bilateral stimulus presentation condition permits the computation of a reversed association that offers additional support for the distinction between two types of spatial-relation representation.

Adult↗

PubMed1988

Processing from LVF, RVF and BILATERAL presentations: examinations of metacontrol and interhemispheric interaction.

Observers indicated whether two successively presented drawings of faces were identical or differed in one feature (hair, eyes, mouth, jaw). The first face of each pair was presented at the fixation point and the second was presented to the left visual field-right hemisphere (LVF-RH), right visual field-left hemisphere (RVF-LH), or to both visual fields simultaneously (BILATERAL). On DIFFERENT trials the RT of correct responses depended on which feature differed and the pattern of feature location effects was significantly different on LVF-RH and RVF-LH trials. On BILATERAL trials the feature location effect was identical to that obtained on RVF-LH trials and significantly different from that obtained on LVF-RH trials. In addition, the percentage of errors and RT of correct responses were both higher on BILATERAL trials than on unilateral trials. Implications of these results are considered for the concept of "metacontrol" in neurologically normal humans and for models of interhemispheric interaction.

Attention↗

PubMed1987

Effects of blurring and stimulus size on the lateralized processing of nonverbal stimuli.

Right-handed subjects indicated whether two novel, nonlinguistic stimuli were physically identical or not. In Experiment 1 blurring these stimuli impaired performance when stimuli were projected to the right visual field but not when stimuli were projected to the left visual field. This lateralized effect of blurring is similar to earlier findings in letter-matching experiments and indicates that such effects do not depend on hemispheric differences in verbal mediation. Experiment 2 examined the lateralized effects of stimulus size using the same task as Experiment 1. The pattern of results from this experiment suggests that both visual spatial frequency and stimulus perceptibility contribute to interactions of stimulus clarity and visual field and that neither factor by itself may be the sole determinant of the lateralized effects of input variables.

Adult↗