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Highlights • Block- and trial-based proactive inhibition can be two modes of slowing behavioral reaction according to contexts. • We established a novel stop-signal task to evaluate the block- and trial-based proactive inhibition separately in rats. • Neural activity in M1, M2, PPC and OFC neurons was differently modulated under the two types of proactive inhibition. • Therefore, different cortical mechanisms may underlie the two types of proactive inhibition in rodents. Abstract Animals can suppress their behavioral response in advance according to changes in environmental context (proactive inhibition: delaying the start of response), a process in which several cortical areas may participate. However, it remains unclear how this process is adaptively regulated according to contextual changes on different timescales. To address the issue, we used an improved stop-signal task paradigm to behaviorally and electrophysiologically characterize the temporal aspect of proactive inhibition in head-fixed rats. In the task, they must respond to a go cue as quickly as possible (go trial), but did not have to respond if a stop cue followed the go cue (stop trial). The task alternated between a block of only go trials (G-block) and a block of go-and-stop trials (GS-block). We observed block-based and trial-based proactive inhibition (emerging in GS-block and after stop trial, respectively) by behaviorally evaluating the delay in reaction time in correct go trials depending on contextual changes on different timescales. We electrophysiologically analyzed task-related neuronal activity in the primary and secondary motor, posterior parietal, and orbitofrontal cortices (M1, M2, PPC, and OFC, respectively). Under block-based proactive inhibition, spike activity of cue-preferring OFC neurons was attenuated continuously, while M1 and M2 activity was enhanced during motor preparation. Subsequently, M1 activity was attenuated during motor decision/execution. Under trial-based proactive inhibition, the OFC activity was continuously enhanced, and PPC and M1 activity was also enhanced shortly during motor decision/execution. These results suggest that different cortical mechanisms underlie the two types of proactive inhibition in rodents. [ABSTRACT FROM AUTHOR]

Inhibition of return (IOR) refers to the relative suppression of processing at locations that have recently been attended. It is frequently explored using a spatial cueing paradigm and is characterized by slower responses to cued than to uncued locations. The current study investigates the impact of IOR on overt visual orienting involving saccadic eye movements. Using a spatial cueing paradigm, our experiments have demonstrated that at a cue- target onset asynchrony (CTOA) of 400 ms saccades to the vicinity of cued locations are not only delayed (temporal cost) but also biased away (spatial effect). Both of these effects are basically no longer present at a CTOA of 1200 ms. At a shorter 200 ms CTOA, the spatial effect becomes stronger while the temporal cost is replaced by a temporal benefit. These findings suggest that IOR has a spatial effect that is dissociable from its temporal effect. Simulations using a neural field model of the superior colliculus (SC) revealed that a theory relying on short-term depression (STD) of the input pathway can explain most, but not all, temporal and spatial effects of IOR. [ABSTRACT FROM AUTHOR]

Inhibition has been implicated as an important mechanism for task-set control, ensuring the efficient selection of the to-be-performed task over alternative possibilities. Across three experiments we demonstrated the effects of two potentially different types of task inhibition. The first is the inhibition of a task that concurrently affords an incongruent response, which is labelled dimension inhibition (Goschke, 2000). Using targets that afford three tasks, we demonstrated that this only occurs when a single alternative task affords an incongruent response, with the inhibition being specific to that task. The second type of inhibition that we observed was backwards inhibition—the suppression of a recently abandoned task-set (Mayr & Keele, 2000). Unlike dimension inhibition, backwards inhibition was not triggered by the response incongruence of the unperformed tasks, or even whether the target afforded responses via the unperformed tasks. These two purported types of inhibition did not co-occur, and neither did the factors of response congruence and whether that task was recently abandoned interact. We therefore suggest that task-specific inhibition can be applied/triggered differently depending upon the paradigm, perhaps depending upon the extent to which alternative tasks, and therefore potentially other responses, are triggered by the target. [ABSTRACT FROM AUTHOR]

This is a review of the reversed-reward contingency (RRC) paradigm in animals and the cognitive functions on which it is founded. I shall present the RRC basic paradigm and the ensuing modifications it underwent, the animals tested, the results obtained and the analyses offered within the literature. Then I would the claim that RRC is a case of a compound cognitive behavior, one that is the result of interactions between three other cognitive functions: crude numerical assessment and economic choice (uniting value assignment and behavioral inhibition). I will present data concerning these three fields and will demonstrate how they are both affecting and affected by the findings of the RRC scheme. RRC is treated here as a test case for a broader type of analysis, one which, hopefully, will show that in order to fully understand composite and complex behavior we need to meticulously explore its building blocks and their dynamic interplay. [ABSTRACT FROM AUTHOR]

Castel, Pratt, and Craik (2003) have shown that inhibition of return (IOR, the delayed response to a recently cued item) is disrupted by a secondary task that involves spatial working memory (WM), and they suggest that IOR is mediated by spatial WM. However, they did not specify what kind of IOR was involved. We used a dual-task paradigm to examine whether the two kinds of IOR (location- and object-based IOR) are affected by two kinds of secondary task that involve spatial and nonspatial WM, respectively. The results show that location-based IOR was disrupted by a spatial secondary task while the object-based IOR was disrupted by a nonspatial secondary task. The present study further elaborates the conclusion of Castel et al. (2003) by differentiating the effect of the two kinds of WM (spatial vs. nonspatial) on the two kinds of IOR (location based vs. object based). [ABSTRACT FROM AUTHOR]