When shown a digit and its negative image at a slow rate of alternation (Fig. 1a), participants have no trouble identifying it.
As the rate of alternation increases, a sharp threshold is reached after which the information is presented too rapidly and the digit can no longer be discriminated from a uniform display (Fig. 1b) – that is, at a high rate of alternation the images perceptually overlap as though they were presented simultaneously.
Tc1 transchromosomic mice show comparable rates of alternation to euploid control mice (O'Doherty et al., 2005).
Under these conditions, SREB2 Tg mice had normal rates of alternation when the delays were relatively low, but did not perform above random when the delay was increased to a moderate interval at which the WT mice still performed well.
The rate of spontaneous alternation (visiting each arm in turn) was greater than 50% for each of the four groups.
In contrast, CrT −/y mice showed a significantly smaller rate of spontaneous alternation with respect to WT controls (t test, p < 0.05, Figure 5c).
Furthermore, we examined whether the bilateral SPL regions play a causal role in the rate of perceptual alternations by using transcranial magnetic stimulation (TMS) and found that transient disruption of these areas indeed decreases the rate of perceptual alternations.
In studies on binocular rivalry, it is known that the contrast of the images strongly influences the dynamics: When the contrast of both images is lowered, the rate of perceptual alternations will decrease (e.g., Brascamp, van Ee, Noest, Jacobs, & van den Berg, 2006; Levelt, 1968).
The rates of spontaneous alternation were identical in the mutants and their WT littermates, Del 59±3% (n = 17) and WT 58±2% (n = 17), indicating no difference in short-term working memory.
Moreover, in a future system, it would be better to be able to adjust the rate of visual field alternation according to the magnification of the lens. 5.
Moreover, in a future system, it would be better to be able to adjust the rate of visual field alternation according to the magnification of the lens.
