Temporal estimation with two moving objects: overt and covert pursuit

The current study examined temporal estimation in a prediction motion task where participants were cued to overtly pursue one of two moving objects, which could either arrive first, i.e., shortest [time to contact (TTC)] or second (i.e., longest TTC) after a period of occlusion. Participants were instructed to estimate TTC of the first-arriving object only, thus making it necessary to overtly pursue the cued object while at the same time covertly pursuing the other (non-cued) object. A control (baseline) condition was also included in which participants had to estimate TTC of a single, overtly pursued object. Results showed that participants were able to estimate the arrival order of the two objects with very high accuracy irrespective of whether they had overtly or covertly pursued the first-arriving object. However, compared to the single-object baseline, participants’ temporal estimation of the covert object was impaired when it arrived 500 ms before the overtly pursued object. In terms of eye movements, participants exhibited significantly more switches in gaze location during occlusion from the cued to the non-cued object but only when the latter arrived first. Still, comparison of trials with and without a switch in gaze location when the non-cued object arrived first indicated no advantage for temporal estimation. Taken together, our results indicate that overt pursuit is sufficient but not necessary for accurate temporal estimation. Covert pursuit can enable representation of a moving object’s trajectory and thereby accurate temporal estimation providing the object moves close to the overt attentional focus

Processing of translational, radial and rotational optic flow in older adults

Abstract Aging impacts human observer’s performance in a wide range of visual tasks and notably in motion discrimination. Despite numerous studies, we still poorly understand how optic flow processing is impacted in healthy older adults. Here, we estimated motion coherence thresholds in two groups of younger (age: 18–30, n = 42) and older (70–90, n = 42) adult participants for the three components of optic flow (translational, radial and rotational patterns). Stimuli were dynamic random-dot kinematograms (RDKs) projected on a large screen. Participants had to report their perceived direction of motion (leftward versus rightward for translational, inward versus outward for radial and clockwise versus anti-clockwise for rotational patterns). Stimuli had an average speed of 7°/s (additional recordings were performed at 14°/s) and were either presented full-field or in peripheral vision. Statistical analyses showed that thresholds in older adults were similar to those measured in younger participants for translational patterns, thresholds for radial patterns were significantly increased in our slowest condition and thresholds for rotational patterns were significantly decreased. Altogether, these findings support the idea that aging does not lead to a general decline in visual perception but rather has specific effects on the processing of each optic flow component

Are mycotoxins relevant to be studied in health care environments?

Project EXPOsE, nº 23222 (02/SAICT/2016)Mycotoxins are fungi metabolites produced by specific fungal genera and although the reported evidence about the health effects there is still a gap about data in health care environments. This study aimed to investigate if mycotoxins presence should be monitored in health care facilities by searching for studies that reported fungal contamination by toxigenic fungi in different health care environments. The study involved a systematic search of available information/data published on PubMed during the period of 2010 until 31st December 2018. Among the 26 papers analyzed, only in two the Aspergillus genera were not reported as the most prevalent. Additionally, other genera also with toxigenic potential were observed, namely Fusarium and Penicillium. The information gathered with this review allowed to conclude about the importance to assess mycotoxins in health care environments. Moreover, the analytical methods used should allow detecting low concentrations and multiple mycotoxins.info:eu-repo/semantics/publishedVersio