Attentional Functions of the Superior Colliculus

Author(s):  
Richard J. Krauzlis

The superior colliculus (SC) plays an important role in both overt and covert attention. In primates, the SC is well known to be a central component of the motor pathways that orient the eyes and head to important objects in the environment. Accordingly, neurons in the SC show enhanced responses that will be the target of orienting movements, compared to stimuli that will be ignored. Single-neuron recordings in the SC have revealed a variety of attention-related effects, including changes in activity related to bottom-up and top-down attention, attention capture, and inhibition of return. These findings support the view of the SC as a priority map that represents the location of important objects in the visual environment. Manipulation of SC activity by electrical microstimulation and chemical inactivation shows that the SC is not simply a recipient of attention-related effects, but plays a causal role in these processes. In particular, activity in the SC plays a major role in the selection of targets for saccades, and also for pursuit eye movements and movements of the hand. Moreover, activity in the SC is important not only for the control of overt attention, but also plays a crucial role in covert attention—the processing of visual signals for perceptual judgements even in the absence of orienting movements. The mechanisms mediating the role of the SC in the control of covert attention are not yet known, but current models emphasize interactions between the SC and areas of the cerebral cortex.

2012 ◽  
Vol 5 (5) ◽  
Author(s):  
Heinz-Werner Priess ◽  
Sabine Born ◽  
Ulrich Ansorge

Inhibition of return (IOR) is the faster selection of hitherto unattended than previously attended positions. Some previous studies failed to find evidence for IOR after attention capture by color singletons. Others, however, did report IOR effects after color singletons. The current study examines the role of cue relevance for obtaining IOR effects. By using a potentially more sensitive method – saccadic IOR – we tested and found IOR after relevant color singleton cues that required an attention shift (Experiment 1). In contrast, irrelevant color singletons failed to produce reliable IOR effects in Experiment 2. Also, Experiment 2 rules out an alternative explanation of our IOR findings in terms of masking. We discuss our results in light of pertaining theories of IOR.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jaclyn Essig ◽  
Joshua B. Hunt ◽  
Gidon Felsen

AbstractDecision making is a cognitive process that mediates behaviors critical for survival. Choosing spatial targets is an experimentally-tractable form of decision making that depends on the midbrain superior colliculus (SC). While physiological and computational studies have uncovered the functional topographic organization of the SC, the role of specific SC cell types in spatial choice is unknown. Here, we leveraged behavior, optogenetics, neural recordings and modeling to directly examine the contribution of GABAergic SC neurons to the selection of opposing spatial targets. Although GABAergic SC neurons comprise a heterogeneous population with local and long-range projections, our results demonstrate that GABAergic SC neurons do not locally suppress premotor output, suggesting that functional long-range inhibition instead plays a dominant role in spatial choice. An attractor model requiring only intrinsic SC circuitry was sufficient to account for our experimental observations. Overall, our study elucidates the role of GABAergic SC neurons in spatial choice.


2010 ◽  
Author(s):  
Aja Taitano ◽  
Bradley Smith ◽  
Cade Hulbert ◽  
Kristin Batten ◽  
Lalania Woodstrom ◽  
...  

2016 ◽  
Vol 04 (01) ◽  
pp. 4-10

AbstractImmunosuppression permits graft survival after transplantation and consequently a longer and better life. On the other hand, it increases the risk of infection, for instance with cytomegalovirus (CMV). However, the various available immunosuppressive therapies differ in this regard. One of the first clinical trials using de novo everolimus after kidney transplantation [1] already revealed a considerably lower incidence of CMV infection in the everolimus arms than in the mycophenolate mofetil (MMF) arm. This result was repeatedly confirmed in later studies [2–4]. Everolimus is now considered a substance with antiviral properties. This article is based on the expert meeting “Posttransplant CMV infection and the role of immunosuppression”. The expert panel called for a paradigm shift: In a CMV prevention strategy the targeted selection of the immunosuppressive therapy is also a key element. For patients with elevated risk of CMV, mTOR inhibitor-based immunosuppression is advantageous as it is associated with a significantly lower incidence of CMV events.


Author(s):  
Palky Mehta ◽  
H. L. Sharma

In the current scenario of Wireless Sensor Network (WSN), power consumption is the major issue associated with nodes in WSN. LEACH technique plays a vital role of clustering in WSN and reduces the energy usage effectively. But LEACH has its own limitation in order to search cluster head nodes which are randomly distributed over the network. In this paper, ERA-NFL- BA algorithm is being proposed for selects the cluster heads in WSN. This algorithm help in selection of cluster heads can freely transform from global search to local search. At the end, a comparison has been done with earlier researcher using protocol ERA-NFL, which clearly shown that proposed Algorithm is best suited and from comparison results that ERA-NFL-BA has given better performance.


2019 ◽  
Vol 16 (2-3) ◽  
pp. 161-179
Author(s):  
Outi Paloposki

The article looks at book production and circulation from the point of view of translators, who, as purchasers and readers of foreign-language books, are an important mediating force in the selection of literature for translation. Taking the German publisher Tauchnitz's series ‘Collection of British Authors’ and its circulation in Finland in the nineteenth and early twentieth century as a case in point, the article argues that the increased availability of English-language books facilitated the acquiring and honing of translators' language skills and gradually diminished the need for indirect translating. Book history and translation studies meet here in an examination of the role of the Collection in Finnish translators' work.


2013 ◽  
Vol 6 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Vanessa Joosen

Compared to the attention that children's literature scholars have paid to the construction of childhood in children's literature and the role of adults as authors, mediators and readers of children's books, few researchers have made a systematic study of adults as characters in children's books. This article analyses the construction of adulthood in a selection of texts by the Dutch author and Astrid Lindgren Memorial Award winner Guus Kuijer and connects them with Elisabeth Young-Bruehl's recent concept of ‘childism’ – a form of prejudice targeted against children. Whereas Kuijer published a severe critique of adulthood in Het geminachte kind [The despised child] (1980), in his literary works he explores a variety of positions that adults can take towards children, with varying degrees of childist features. Such a systematic and comparative analysis of the way grown-ups are characterised in children's texts helps to shed light on a didactic potential that materialises in different adult subject positions. After all, not only literary and artistic aspects of children's literature may be aimed at the adult reader (as well as the child), but also the didactic aspect of children's books can cross over between different age groups.


Author(s):  
V.N. Zolotarev ◽  
◽  
I.S. Ivanov ◽  
O.N. Lyubtseva

Based on the analysis of data available in the literature and our own experimental material on phytocenotic selection of the stony stalk (Bromopsis inermis Holub.) the important role of competition between plants in the field for the creation of new varieties of perennial grasses that provide high yields of feed polyvid agrophytocenoses is shown.


Sign in / Sign up

Export Citation Format

Share Document