scholarly journals Cloudy with a chance of mesopredator release: Turbidity alleviates top‐down control on intermediate predators through sensory disruption

2020 ◽  
Vol 65 (10) ◽  
pp. 2278-2290
Author(s):  
Joseph W. Reustle ◽  
Delbert L. Smee
2012 ◽  
Vol 34 (1) ◽  
pp. 119 ◽  
Author(s):  
Peter J. S. Fleming ◽  
Benjamin L. Allen ◽  
Guy-Anthony Ballard

Australian dingoes have recently been suggested as a tool to aid biodiversity conservation through the reversal or prevention of trophic cascades and mesopredator release. However, at least seven ecological and sociological considerations must be addressed before dog populations are positively managed.Domestication and feralisation of dingoes have resulted in behavioural changes that continue to expose a broad range of native and introduced fauna to predation.Dingoes and other dogs are classic mesopredators, while humans are the apex predator and primary ecosystem engineers in Australia.Anthropogenic landscape changes could prevent modern dingoes from fulfilling their pre-European roles.Dingoes are known to exploit many of the same species they are often presumed to ‘protect’, predisposing them to present direct risks to many threatened species.The assertion that contemporary dog control facilitates the release of mesopredators disregards the realities of effective dog control, which simultaneously reduces fox and dog abundance and is unlikely to enable increases in fox abundance.The processes affecting threatened fauna are likely a combination of both top-down and bottom-up effects, which will not be solved or reversed by concentrating efforts on managing only predator effects.Most importantly, human social and economic niches are highly variable across the ecosystems where dingoes are present or proposed. Human perceptions will ultimately determine acceptance of positive dingo management.Outside of an adaptive management framework, positively managing dingoes while ignoring these seven considerations is unlikely to succeed in conserving native faunal biodiversity but is likely to have negative effects on ecological, social and economic values.


2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.


2003 ◽  
Vol 14 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Walter Sturm

Abstract: Behavioral and PET/fMRI-data are presented to delineate the functional networks subserving alertness, sustained attention, and vigilance as different aspects of attention intensity. The data suggest that a mostly right-hemisphere frontal, parietal, thalamic, and brainstem network plays an important role in the regulation of attention intensity, irrespective of stimulus modality. Under conditions of phasic alertness there is less right frontal activation reflecting a diminished need for top-down regulation with phasic extrinsic stimulation. Furthermore, a high overlap between the functional networks for alerting and spatial orienting of attention is demonstrated. These findings support the hypothesis of a co-activation of the posterior attention system involved in spatial orienting by the anterior alerting network. Possible implications of these findings for the therapy of neglect are proposed.


2011 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Julia Graf ◽  
Hartwig Kulke ◽  
Christa Sous-Kulke ◽  
Wilfried Schupp ◽  
Stefan Lautenbacher
Keyword(s):  

Aufmerksamkeit kann als Kontrollsystem neuronaler Aktivität verstanden werden, welches Neuroplastizität top-down modulieren hilft. Bisher wurde selten versucht, durch deren gezielte Förderung Funktionswiederherstellungen nach Hirnschädigung zu begünstigen. In vorliegender Studie wurde dies am Beispiel der Aphasie erprobt. 15 Schlaganfallpatienten erhielten ein dreiwöchiges Training der selektiven Aufmerksamkeit mit den PC-Programmen CogniPlus und „Konzentration“ bei fünf Sitzungen pro Woche zusätzlich zur Standardtherapie, 13 weitere bildeten eine Kontrollgruppe ohne Aufmerksamkeitstraining. Zur Effektivitätskontrolle dienten zwei Versionen des Untertests Go/Nogo (Testbatterie zur Aufmerksamkeitsprüfung) und die Kurze Aphasieprüfung. Nach dem Training manifestierte sich zwischen den Untersuchungsgruppen kein Unterschied in Aufmerksamkeits- und Sprachfunktionen; das zusätzliche Aufmerksamkeitstraining war also wirkungslos. Allerdings zeigten Patienten mit deutlichen Aufmerksamkeitsverbesserungen tendenziell weniger Aphasie-Symptome, was die Hypothese aufmerksamkeitsvermittelter Plastizitätsmodulation nach Hirnschädigung partiell stützt.


2001 ◽  
Vol 209 (1) ◽  
pp. 34-53 ◽  
Author(s):  
Rainer Bösel
Keyword(s):  
Top Down ◽  

Zusammenfassung. Aufmerksamkeit wird sowohl als Selektivität in der bewußter Verarbeitung oder auch als selektive neuronale Aktivierung verstanden. Die neuronalen Strukturen, die Objektdiskrimination ermöglichen, erlauben eine Interaktion von datengetriebenen und endogenen top-down Prozessen, die zu einer selektiven Bereitstellung von Verarbeitungs-Ressourcen führen. Zielgerichtetes Verhalten erfordert manchmal einen Wechsel in der Ressourcen-Bereitstellung und eine Konzentration von mentaler Aktivität. Aufmerksamkeitswechsel kann als ein zweiphasiger Prozeß verstanden werden, der aus einer breiten Mobilisierung von Gedächtnis-Ressourcen besteht (angezeigt durch EEG-Theta), gefolgt von einer re-organisierenden Einengung neuronaler Aktivität (angezeigt durch langsames EEG-Alpha). Dieser Beitrag unterstützt die Annahme, daß die Analyse des gekoppelten Wechselspiels aus Mobilisierung und Konzentration in bestimmten Teilen der posterioren und anterioren Rindenregionen ein Schlüssel für das Verständnis von Aufmerksamkeitswechsel sein könnte.


PsycCRITIQUES ◽  
2005 ◽  
Vol 50 (19) ◽  
Author(s):  
Michael Cole
Keyword(s):  
Top Down ◽  

2000 ◽  
Author(s):  
Robin D. Thomas ◽  
Melissa A. Lea ◽  
Mark D. Hammerly
Keyword(s):  

2012 ◽  
Author(s):  
Charles L. Folk ◽  
Deborah Kendzierski ◽  
Brad Wyble

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