Knowing the future: partial foreknowledge effects on the programming of prosaccades and antisaccades

Foreknowledge about the demands of an upcoming trial may be exploited to optimize behavioural responses. In the current study we systematically investigated the benefits of partial foreknowledge--that is, when some but not all aspects of a future trial are known in advance. For this we used an ocular motor paradigm with horizontal prosaccades and antisaccades. Predictable sequences were used to create three partial foreknowledge conditions: one with foreknowledge about the stimulus location only, one with foreknowledge about the task set only, and one with foreknowledge about the direction of the required response only. These were contrasted with a condition of no-foreknowledge and a condition of complete foreknowledge about all three parameters. The results showed that the three types of foreknowledge affected saccadic efficiency differently. While foreknowledge about stimulus-location had no effect on efficiency, task foreknowledge had some effect and response-foreknowledge was as effective as complete foreknowledge. Foreknowledge effects on switch costs followed a similar pattern in general, but were not specific for switching of the trial attribute for which foreknowledge was available. We conclude that partial foreknowledge has a differential effect on efficiency, most consistent with preparatory activation of a motor schema in advance of the stimulus, with consequent benefits for both switched and repeated trials.

The in vitro evidence for an effect of high homeopathic potencies--a systematic review of the literature

OBJECTIVE: Systematic assessment of the in vitro research on high potency effects. METHOD: Publications of experiments were collected through databases, experts, previous reviews, citation tracking. Inclusion criteria: stepwise agitated dilutions <10(-23); cells or molecules from human or animal. Experiments were assessed with the modified SAPEH score. RESULTS: From 75 publications, 67 experiments (1/3 of them replications) were evaluated. Nearly 3/4 of them found a high potency effect, and 2/3 of those 18 that scored 6 points or more and controlled contamination. Nearly 3/4 of all replications were positive. Design and experimental models of the reviewed experiments were inhomogenous, most were performed on basophiles. CONCLUSIONS: Even experiments with a high methodological standard could demonstrate an effect of high potencies. No positive result was stable enough to be reproduced by all investigators. A general adoption of succussed controls, randomization and blinding would strengthen the evidence of future experiments.

Linking physiology with behaviour: Functional specialisation of the visual field is reflected in gaze patterns during visual search

Based on neurophysiological findings and a grid to score binocular visual field function, two hypotheses concerning the spatial distribution of fixations during visual search were tested and confirmed in healthy participants and patients with homonymous visual field defects. Both groups showed significant biases of fixations and viewing time towards the centre of the screen and the upper screen half. Patients displayed a third bias towards the side of their field defect, which represents oculomotor compensation. Moreover, significant correlations between the extent of these three biases and search performance were found. Our findings suggest a new, more dynamic view of how functional specialisation of the visual field influences behaviour.