Biomedical subjects

Hitoshi Honda

Publications and source records attributed to Hitoshi Honda.

3 recordsLinked to original sources

PubMed2006

Achievement of transsaccadic visual stability using presaccadic and postsaccadic visual information.

While saccadic eye movements produce rapid shift of images of objects on the retina, the visual world is perceived as stationary (visual stability), but the precise mechanisms involved in such perception remain unclear. We investigated if visual stimuli existing before and/or after a saccade serve to preserve visual stability. Participants observed a vertical array of light-spots flashing consecutively at the time of horizontal saccades. When total duration of the flashing array was short (38 ms), large distortions of the array were observed. However, as duration increased up to 300 ms, distortion decreased or was completely eliminated. This demonstrated that visual images of a flashing array momentarily perceived before and/or after saccades suppressed illusory distortion of arrays observed when a 38-ms array was used, implying that the same mechanism may be used to achieve transsaccadic visual stability in daily life.

Adult↗

PubMed2005

The remote distractor effect of saccade latencies in fixation-offset and overlap conditions.

Saccadic responses to a visual target are delayed if another visual stimulus (distractor) is presented in the visual field opposite to the target (remote distractor effect). In the present study, two experiments were conducted to investigate how the remote distractor effect is modulated by the presence or absence of a central fixation stimulus. In both experiments, when a fixation stimulus was continuously presented even after target presentation, the remote distractor effect decreased. The reduction of the remote distractor effect was observed for all distractor positions examined (1.5 degrees -9.0 degrees eccentricity), and prominent especially when targets were presented at more peripheral positions (9.0 degrees and 10 degrees eccentricity). It was concluded that these results can be well explained by recent findings on inhibitory interactions among subpopulations of neurons in the superior colliculus.

Fixation, Ocular↗

PubMed2002

Idiosyncratic left-right asymmetries of saccadic latencies: examination in a gap paradigm.

Subjects were given reflexive- and voluntary-saccade tasks using five different gap intervals (0-500 ms) between the fixation point offset and the target onset and an overlap paradigm (i.e., the fixation point remained on during the target presentation). In the first experiment, targets were monocularly presented, and the latencies of reflexive saccades to a peripheral target were compared between the left and right visual fields in which targets were presented. The data averaged over subjects did not show a significant difference of saccade latencies between the two visual fields. However, individual subjects showed strong left/right asymmetries of saccade latencies: six out of the 12 subjects that participated made a saccade more rapidly to the right than to the left, and two other subjects showed the reverse result. In these cases, the left/right asymmetry was observed on both gap and overlap trials. The saccade latencies were not affected by the hemiretina to which a target was projected. The second experiment was conducted to identify conditions under which the left/right asymmetry can be reproduced. For this purpose, five subjects were given both reflexive-saccade and voluntary-saccade tasks. In the latter task, a cue stimulus for generating saccades was given at the central fixation point. Regardless of whether saccades were made reflexively or voluntarily, and whether the targets were viewed monocularly or binocularly, each subject showed the same pattern of left/right asymmetries of saccade latencies. The results were interpreted as showing that a visuo-spatial attentional bias specific to individual subjects is involved in generating idiosyncratic left/right asymmetries of saccade latencies.

Adult↗