Binocular summation is affected by crowding and tagging

In perceptual crowding, a letter easily recognized on its own, becomes unrecognizable if it is surrounded by other letters, an effect that confers a limit on the visual processing. Models assume that crowding is a hallmark of the periphery but that it is almost absent in the fovea. However, recently it was shown that crowding occurs in the fovea of people with an abnormal development of functional vision (amblyopia), when the stimulus is presented for a very short time. When targets and flankers are dissimilar, the crowding is reduced (tagging). Since a combination of binocular inputs increases the processing load, we investigated whether color tagging the target reduces crowding in the fovea of subjects with normal vision and determined how crowding is combined with binocular vision. The crowding effect at the fovea was significantly reduced by tagging with a color target. Interestingly, whereas binocular summation for a single letter was expected to be about 40%, it was significantly reduced and almost absent under crowding conditions. Our results are consistent with the notion that the crowding effect produces a high processing load on visual processing, which interferes with other processes such as binocular summation. We assume that the tagging effect in our experiment improved the subject's abilities (sensitivity and RT) by creating a "segmentation", i.e., a visual simulated separation between the target letter and the background. Interestingly, tagging the target with a distinct color can eliminate or reduce the crowding effect and consequently, binocular summation recovers.

Dermal response to combined double filler administration

Aim. This experimental work presents a comparative assessment of the effect of hyaluronic acid and crystalline calcium hydroxyapatite on derma in separate and combined application setting.Materials and methods. The study used rats (30 animals) for subdermal injection of 0.05 ml medium. Group 1 was administered calcium hydroxyapatite (Radiesse (Merz, Germany)), group 2 received hyaluronic acid (Restylane (SabQ, Sweden)) and Group 3 — both preparations combined in ratio 1:1 (Mix). Results were evaluated 4 months after the filler injection. Sections were stained with haematoxylin–eosin, van Gieson’s and Masson’s trichrome techniques. Collagen types I and III were detected with polyclonal antibodies (Abcam, England). Fibroblasts were positively identified with vimentin (LabVision), macrophages — with CD68 (LabVision) tagging. Effect of extracellular matrix remodelling was studied with α-SMA actin (Abcam, England).Results. We demonstrate that separate filling of hyaluronic acid and calcium hydroxyapatite produces different response mechanisms, while their combined administration does not lead to a marked voluming of the dermal extracellular matrix.Conclusion. Combined administration of the two fillers under study may facilitate a prolonged effect of their combined action exceeding 4 months, due to the absence of fibrosis, complications and side effects.

Inhibitory Tagging on Randomly Moving Objects

Inhibitory tagging is a process that prevents focal attention from revisiting previously checked items in inefficient searches, facilitating search performance. Recent studies suggested that inhibitory tagging is object rather than location based, but it was unclear whether inhibitory tagging operates on moving objects. The present study investigated the tagging effect on moving objects. Participants were asked to search for a moving target among randomly and independently moving distractors. After either efficient or inefficient search, participants performed a probe detection task that measured the inhibitory effect on search items. The inhibitory effect on distractors was observed only after inefficient searches. The present results support the concept of object-based inhibitory tagging.