Selective manipulation of target identification demands in visual search: The role of stimulus contrast in CDA activations

Abstract The uremic syndrome is a complex clinical picture developing in the advanced stages of chronic kidney disease (CKD) resulting in a myriad of complications and a high early mortality. This picture is to a significant extent defined by retention of metabolites and peptides that with a preserved kidney function are excreted or degraded by the kidneys. In as far as those solutes have a negative biological/biochemical impact, they are called uremic toxins. Here, we describe the historical evolution of the scientific knowledge about uremic toxins and the role played in this process by the European Uremic Toxin Work Group (EUTox) during the last two decades. The earliest knowledge about a uremic toxin goes back to the early 17th century when the existence of what later would appear to be urea was recognized. It cost about two further centuries to better define the role of urea and its link to kidney failure and one more century to identify the relevance of post-translational modifications caused by urea such as carbamoylation. The knowledge progressively extended, especially from 1980 on, by the identification of more and more toxins and their adverse biological/biochemical impact. Progress of knowledge was paralleled and impacted by evolution of dialysis strategies. The last two decades, when Insights grew exponentially, coincides with the foundation and activity of EUTox. In the final section we summarize the role and accomplishments of EUTox and the part it is likely to play in future action, which should be organized around focus points like biomarker and potential target identification, intestinal generation, toxicity mechanisms and their correction, kidney and extracorporeal removal, patient-oriented outcomes, and toxin characteristics in acute kidney injury and transplantation.

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The role of memory for visual search in scenes

Annals of the New York Academy of Sciences ◽

10.1111/nyas.12667 ◽

2015 ◽

Vol 1339 (1) ◽

pp. 72-81 ◽

Cited By ~ 49

Author(s):

Melissa Le-Hoa Võ ◽

Jeremy M. Wolfe

Keyword(s):

Visual Search

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Aging and guided visual search: the role of visual working memory

Aging Neuropsychology and Cognition ◽

10.1080/13825585.2017.1344185 ◽

2017 ◽

Vol 25 (4) ◽

pp. 535-549 ◽

Cited By ~ 1

Author(s):

Sowon Hahn ◽

Daniel R. Buttaccio

Keyword(s):

Working Memory ◽

Visual Search ◽

Visual Working Memory

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Genetic disruption of the On visual pathway affects cortical orientation selectivity and contrast sensitivity in mice

Journal of Neurophysiology ◽

10.1152/jn.00558.2013 ◽

2014 ◽

Vol 111 (11) ◽

pp. 2276-2286 ◽

Cited By ~ 6

Author(s):

Rashmi Sarnaik ◽

Hui Chen ◽

Xiaorong Liu ◽

Jianhua Cang

Keyword(s):

Contrast Sensitivity ◽

Visual Pathway ◽

Response Variability ◽

Stimulus Contrast ◽

Wild Type ◽

Low Contrast ◽

Pharmacological Blockade ◽

Single Unit Recordings ◽

On And Off Pathways

The retina signals stimulus contrast via parallel On and Off pathways and sends the information to higher visual centers. Here we study the role of the On pathway using mice that have null mutations in the On-specific GRM6 receptor in the retina (Pinto LH, Vitaterna MH, Shimomura K, Siepka SM, Balannik V, McDearmon EL, Omura C, Lumayag S, Invergo BM, Brandon M, Glawe B, Cantrell DR, Donald R, Inayat S, Olvera MA, Vessey KA, Kirstan A, McCall MA, Maddox D, Morgans CW, Young B, Pletcher MT, Mullins RF, Troy JB, Takahashi JS. Vis Neurosci 24: 111–123, 2007; Maddox DM, Vessey KA, Yarbrough GL, Invergo BM, Cantrell DR, Inayat S, Balannik V, Hicks WL, Hawes NL, Byers S, Smith RS, Hurd R, Howell D, Gregg RG, Chang B, Naggert JK, Troy JB, Pinto LH, Nishina PM, McCall MA. J Physiol 586: 4409–4424, 2008). In these “nob” mice, single unit recordings in the primary visual cortex (V1) reveal degraded selectivity for orientations due to an increased response at nonpreferred orientations. Contrast sensitivity in the nob mice is reduced with severe deficits at low contrast, consistent with the phenotype of night blindness in human patients with mutations in Grm6. These cortical deficits can be largely explained by reduced input drive and increased response variability seen in nob V1. Interestingly, increased variability is also observed in the superior colliculus of these mice but does not affect its tuning properties. Further, the increased response variability in the nob mice is traced to the retina, a result phenocopied by acute pharmacological blockade of the On pathway in wild-type retina. Together, our results suggest that the On and Off pathways normally interact to increase response reliability in the retina, which in turn propagates to various central visual targets and affects their functional properties.

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