SD of synchronizing error.

<p>The SD of synchronizing error at each ISI are shown. The SD of synchronization error in SCA patients was significantly larger than that of normal subjects at ISIs 500–1200 ms, but was comparable at ISIs 1800–4800 ms. This suggests that the synchronizing tapping in SCA patients was disrupted at shorter ISIs (500–1200 ms).</p

The synchronizing error.

<p>Data are shown in mean ± standard deviation</p><p>*significant deviation from 0 ms after transition zone (delayed tapping time)</p><p>The synchronizing error.</p

Synchronized tapping task.

<p>The subjects tapped the keyboard in synchrony with the sequences of auditory tones presented at fixed interstimulus intervals (ISIs) between 200 and 4800 ms. We measured the time difference (synchronizing error) between the times of tap (white arrows) and those of tones (black arrows) and the time interval between successive taps (ITI) in each trial.</p

The ratio of ITI to ISI.

<p>The ratio of average ITI to ISI is plotted in each ISI. The red curve is for SCA patients and the blue curve for normal subjects. Asterisks indicate significant difference between the two groups.</p

Representative distributions of synchronizing error.

<p>Distributions of synchronizing error (the time of button responses relative to the tone) are depicted as histograms in a normal subject (A) and a SCA patient (B). In a normal subject, at shorter ISIs, the histogram for synchronizing error shows a unimodal distribution which was centered around or a slightly negative value, whereas when ISI becomes more variable at intermediate ISIs (transition zone), it finally converges into a unimodal distribution delayed relative to the tone. In SCA patients, however, the unimodal distributions at shorter ISIs are not observed. Additionally, the earliest time of delayed tapping appears earlier compared to normal subjects. Consequently, the temporal processing is disrupted and the ‘3 second rule’ is shortened in SCA patients.</p

Heat maps in serial search tasks.

<p>A: SCA patients, B: normal subjects. In both 4- and 48-itemt tasks, the areas (colored areas) scanned by SCA patients were distributed more widely than those of normal subjects. The center was also colored because the starting eye-fixation position was located at the center of image.</p

Time in all visual tasks.

<p>Time in all visual tasks.</p

Cerebral hemorrhage from putamen (image 2).

<p>A: Region of interest (ROI) surrounding the large hemorrhagic area, B: dwell time in the ROI (A), C: ROI surrounding the intra-ventricular hemorrhage, D: dwell time in the ROI (C). The dwell time in the large hemorrhagic area did not significantly differ between the two groups (B), whereas the dwell time in the intra-ventricular hemorrhage was significantly longer for neurologists than for controls (D).</p

Representative eye movements.

<p>Eye movements in the 4-item serial search task are shown for an SCA patient (A) and a normal subject (B). In the SCA patient, the ocular fixation positions frequently did not fall exactly on the visual target, but landed at points somewhat removed from the target (saccadic dysmetria). In addition, we also observed something we term “repeated fixations (re-fixations)”. Here, the gaze initially captures the target item and then moves away before returning to the target item. To count the number of re-fixations, the target Landolt figure was selected as the region of interest.</p

Search time of visual tasks.

<p>A: simple reaction time, B: direction and color discrimination time, C: serial and pop-out search time. The bars show the values of mean and standard error. Grey bars are for SCA patients and white bars for normal subjects. The simple reaction time was longer in SCA patients than in normal subjects. The direction and color discrimination time had no statistical differences. The 4- and 48-item serial search time was longer in SCA patients than in normal subjects, whereas the 4- and 48-item pop-out search time in SCA patients was almost identical to that in normal subjects. The serial search time was markedly longer than the pop-out search time in both SCA patients and normal subjects.</p