Measuring response inhibition with a continuous inhibitory-control task.

Inhibitory control enables subjects to quickly react to unexpected changes in external demands. In humans, this kind of behavioral flexibility is often used as an indicator of an individual's executive functions, and more and more research has emerged to investigate this link in nonhuman animals as well. Here we explored the value of a recently developed continuous inhibitory-control task in assessing inhibitory-control capacities in animals. Pigeons completed a response-inhibition task that required them to adjust their movement in space in pursuit of a reward across changing target locations. Inhibition was measured in terms of movement trajectory (path taken toward the correct location for trials in which the target location did and did not change) and velocity (both before and after correcting the trajectory toward the changed location). Although the observed velocities did not follow any of our predictions in a clear way, the pigeons' movement trajectories did prove to be a good indicator of inhibitory control, showing that pigeons, though limited in their capacities relative to the sophisticated control strategies expressed by humans, are capable of exerting some forms of inhibitory control. These results strengthen the role of this paradigm as a valuable tool for evaluating inhibitory-control abilities across the animal kingdom.

Behavioral flexibility: A review, a model, and some exploratory tests.

This paper aimed to explore and clarify the concept of behavioral flexibility. A selective literature review explored how the concept of behavioral flexibility has been used in ways that range from acknowledging the fact that animals' behavior is not always bounded by instinctual constraints, to describing the variation between species in their capacity for innovative foraging, a capacity that has repeatedly been linked to having a brain larger than would be predicted from body size. This wide range of usages of a single term has led to some conceptual confusion. We sought to find a more precise meaning for behavioral flexibility by representing it within a simple formal model of problem solving. The key to our model is to distinguish between an animal's state of knowledge about the world and its observable behavior, using a construct of response strength to represent that underlying knowledge. We modelled behavioral flexibility as a parameter in the function that transforms response strengths into observable response probabilities. We tested this model in simulations based on some recent experimental work on animal problem solving. Initial results showed that parametric manipulation can mimic some of the behavioral effects that have been attributed to flexibility.

Limits of Executive Control: Sequential Effects in Predictable Environments.

Cognitive-control theories attribute action control to executive processes that modulate behavior on the basis of expectancy or task rules. In the current study, we examined corticospinal excitability and behavioral performance in a go/no-go task. Go and no-go trials were presented in runs of five, and go and no-go runs alternated predictably. At the beginning of each trial, subjects indicated whether they expected a go trial or a no-go trial. Analyses revealed that subjects immediately adjusted their expectancy ratings when a new run started. However, motor excitability was primarily associated with the properties of the previous trial, rather than the predicted properties of the current trial. We also observed a large latency cost at the beginning of a go run (i.e., reaction times were longer for the first trial in a go run than for the second trial). These findings indicate that actions in predictable environments are substantially influenced by previous events, even if this influence conflicts with conscious expectancies about upcoming events.

Associatively mediated stopping: Training stimulus-specific inhibitory control.

Response inhibition is often considered to be a deliberate act of cognitive control. However, our and other research suggests that when stimuli are repeatedly paired with an inhibitory response, inhibition can become automatized. Currently, relatively little research has focused on the nature of the associative structure that underpins stimulus-specific inhibitory training. In this study, we investigated what associations can be learned in stop-signal training tasks, distinguishing between indirect priming of the stop signal and direct activation of a stop response. We employed a novel paradigm, in which colored cues were stochastically paired with a number of stop signals, and demonstrated that cues consistently paired with stopping reduced commission errors and slowed reaction times. Furthermore, we showed that manipulating the pairings between stimuli and stop signals in a manner that favored the formation of stimulus-stop associations produced enhanced stop learning effects on reaction times, but not on probabilities of responding. Our results suggest that the perceptual processes supporting signal detection (priming) as well as inhibitory processes are involved in inhibitory control training, and that inhibition training may benefit from reducing the contingency between stimuli and stop signals.

The Face Inversion Effect: Roles of First- and Second-Order Configural Information.

The face inversion effect (FIE) is a reduction in recognition performance for inverted faces compared with upright faces. Several studies have proposed that a type of configural information, called second-order relational information, becomes more important with increasing expertise and gives rise to the FIE. However, recently it has been demonstrated that it is possible to obtain an FIE with facial features presented in isolation, showing that configural information is not necessary for this effect to occur. In this article we test whether there is a role for configural information in producing the FIE and whether second- or first-order relational information is particularly important. In Experiment 1, we investigated the role of configural information and local feature orientation by using a new type of "Thatcherizing" transformation on our set of faces, aiming to disrupt second-order and local feature orientation information but keeping all first-order properties unaltered. The results showed a significant reduction in the FIE for these "new" Thatcherized faces, but it did not entirely disappear. Experiment 2 confirmed the FIE for new Thatcherized faces, and Experiment 3 establishes that both local feature orientation and first-order relational information have a role in determining the FIE.

Assessment of anti-Salmonella activity of boot dip samples.

The introduction of pathogens from the external environment into poultry houses via the boots of farm workers and visitors presents a significant risk. The use of boot dips containing disinfectant to help prevent this from happening is common practice, but the effectiveness of these boot dips as a preventive measure can vary. The aim of this study was to assess the anti-Salmonella activity of boot dips that are being used on poultry farms. Boot dip samples were collected from commercial laying hen farms in the UK and tested within 24 hours of receipt at the laboratory to assess their anti-Salmonella activity. All boot dip samples were tested against a field strain of Salmonella enterica serovar Enteritidis using three test models: pure culture, paper disc surface matrix and yeast suspension model. Of the 112 boot dip samples tested 83.6% were effective against Salmonella in pure culture, 37.3% in paper disc surface matrix and 44.5% in yeast suspension model. Numerous factors may influence the efficacy of the disinfectants. Disinfectants used in the dips may not always be fully active against surface or organic matter contamination; they may be inaccurately measured or diluted to a concentration other than that specified or recommended; dips may not be changed regularly or may have been exposed to rain and other environmental elements. This study showed that boot dips in use on poultry farms are frequently ineffective.

Association of mildly elevated pulmonary vascular resistance with major cardiovascular events in pulmonary hypertension and chronic kidney disease: A retrospective cohort analysis.

Pulmonary hypertension (PH) is associated with adverse outcomes in chronic kidney disease (CKD) patients. Our study suggests mildly elevated pulmonary vascular resistance ( > 2 to ≤ 3) is independently associated with major adverse cardiovascular events at 1-year follow-up. Early diagnosis of precapillary PH in CKD patients can potentially improve clinical outcomes.

Assessment of the anti-Salmonella activity of commercial formulations of organic acid products.

Organic acid products are widely used in the UK poultry industry as feed or water additives. Claims for Salmonella control are made for some of these products, but there are few studies comparing the anti-Salmonella effect of the various products in tests that reflect field application. The present studies examined the effects of 13 commercial blends (four water products and nine feed products) on Salmonella Enteritidis and Typhimurium strains. Initial screening, in nutrient broth, of all products with all strains revealed little variation between strains in respect of maximum inhibitory and bactericidal dilutions of each product. However, between the products there was wide and significant variation in the maximum inhibitory and bactericidal dilutions, spanning a 700-fold range in the case of bactericidal dilutions for feed-associated products. Further tests were performed, examining reductions in inoculated Salmonella numbers in various matrices (water, feed, soiled litter, crop and caecal contents) following the addition of the products at recommended inclusion rates. One product, incorporating formaldehyde in addition to organic acid, was consistently most active in all matrices, exceeding reductions associated with other products by 1 to 3 log units at most time points. Many products showed only modest anti-Salmonella activity, amounting to 0 or 1 log unit above negative controls at many time points, and the most active products were not the same in all matrices. Tap water appeared to enhance the ability of products to reduce Salmonella, in comparison with bottled mineral or river water.

Modulating perceptual learning indexed by the face inversion effect: Simulating the application of transcranial direct current stimulation using the MKM model.

We report here two large studies investigating the effects of an established transcranial direct current stimulation (tDCS) procedure on perceptual learning as indexed by the face inversion effect. Experiments 1a and 1b (n = 128) examined the harmful generalization from Thatcherized faces to normal faces by directly comparing the size of the inversion effect for normal faces when presented intermixed with Thatcherized faces (Experiment 1a) versus that obtained when normal faces were presented intermixed with checkerboards (Experiment 1b). The results from the sham/control tDCS groups provide the first direct evidence in the literature showing how Thatcherized faces generalize onto normal ones producing a reduced inversion effect compared to when normal faces are presented with stimuli (e.g., checkerboards) that do not generalize significantly to normal faces. In the anodal tDCS groups, this effect was reversed, with a larger inversion effect recorded for normal faces in Experiment 1a versus that found in Experiment 1b. Further analyses within each experiment confirmed that the anodal tDCS procedure can enhance the inversion effect for normal faces in circumstances where harmful generalization would otherwise be produced by the Thatcherized faces (Experiment 1a). We also demonstrated our standard reduction in the inversion effect for normal faces consequent on the application of tDCS when presented intermixed with stimuli that do not generalize onto them. We interpret our results in terms of simulations using the MKM model of perceptual and associative learning. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Role of interleukins, IGF and stem cells in BPH.

The condition known as benign prostatic hyperplasia may be defined as a benign enlargement of the prostate gland resulting from a proliferation of both benign epithelial and stromal elements. It might also be defined clinically as a constellation of lower urinary tract symptoms (LUTSs) in aging men. The purpose of this review is to consider the ways in which inflammatory cytokines belonging to the interleukin family, members of the IFG family, and stem cells may contribute to the development and progression of BPH-LUTS. This might occur in three mechanisms: One, interleukin signaling, IFG signaling and stem cells may contribute to reactivation of developmental growth mechanisms in the adult prostate leading to tissue growth. Two, given that epidemiologic studies indicate an increased incidence of BPH-LUTS in association with obesity and diabetes, IFG signaling may provide the mechanistic basis for the effect of diabetes and obesity on prostate growth. Three, expression of interleukins in association with inflammation in the prostate may induce sensitization of afferent fibers innervating the prostate and result in increased sensitivity to pain and noxious sensations in the prostate and bladder and heightened sensitivity to bladder filling.

Urolithiasis in a rural Wisconsin population from 1992 to 2008: narrowing of the male-to-female ratio.

PURPOSE: Urolithiasis is a common disease with multiple etiologies and risk factors. Studies suggest an increased incidence in developed nations in recent decades as well as differential geographic incidence and prevalence rates, and differences between the genders. We updated urolithiasis epidemiological data by examining the incidence and prevalence rates in a stable rural Wisconsin population. MATERIALS AND METHODS: Data were obtained from the Marshfield Epidemiologic Study Area database, a surveillance tool created in 1991 to track disease in residents of an area of 24 ZIP Codes including approximately 85,000 individuals, of whom most receive care at Marshfield Clinic and affiliates. Urolithiasis cases were identified using ICD-9 codes. Incidence, prevalence and recurrence rates were determined. RESULTS: The mean age adjusted incidence of new onset urolithiasis per 100,000 person-years was 202 (95% CL 168-235) in 1992 and 289 (95% CL 253-325) in 2008. In women the increase per 100,000 person-years was higher than in men, that is 171 (95% CL 129-213) and 289 (95% CL 238-340) vs 238 (95% CL 184-290) and 296 (95% CL 244-348), respectively. The male-to-female incidence ratio decreased from 1.4 to 1.0. The age adjusted prevalence per 100,000 individuals was 1,968 (2%) and 3,554 (3.5%) in 1992 and 2008, respectively. The increase in women was higher than in men (52% vs 26%). The age adjusted recurrence rate per 100,000 individuals was 553 (0.72%) and 676 (1.0%) in 1992 and 2008, respectively. The increase in women was higher than in men (88% vs 20%). CONCLUSIONS: Since 1992, urolithiasis incidence, prevalence and recurrence rates in this rural Wisconsin population have increased with higher increases noted in women. While prevalence increased, it was lower than reported in other geographic areas in the United States.

Evaluation of commonly-used farm disinfectants in wet and dry models of Salmonella farm contamination.

Two experimental models of Salmonella contamination were used in an attempt to mimic the conditions of disinfectant use on farms. A wet model, for conditions such as boot dips, used disinfectant application to a slurry of poultry faeces inoculated with Salmonella Enteritidis or Salmonella Typhimurium. A dry model, for disinfectant application to surfaces and equipment with adherent or residual organic material, used Salmonella-inoculated poultry faeces that were air-dried onto wooden dowels, immersed in disinfectant solution then left in air at room temperature overnight. All samples were subjected to a disinfectant neutralization step and resuscitation in broth, followed by Salmonella culture on semi-solid then indicator media. Disinfectants were tested at 0.5x, 1x and 2x the concentrations specified for the general control of bacterial pathogens on livestock premises in the UK (Defra General Orders rates). Chlorocresol-based disinfectants provided consistently high rates of Salmonella killing in both wet and dry tests. Formaldehyde-containing disinfectants showed very high efficacy in the dry test but were less effective in the shorter wet test, whereas the efficacy of glutaraldehyde without formaldehyde was variable between products. Other chemical classes tested (quaternary ammonium compounds, amphoteric surfactants, iodine preparations, peroxygens and a substituted phenol blend) were only moderately effective. They often required concentrations above General Orders rates to eliminate the test salmonellas, and frequently elimination was not achieved even under maximal conditions of concentration and exposure.

PEP Does Not Dispense with but Implements Task-Set Reconfiguration. Can It Handle Phenomena More Diagnostic of Endogenous Control?

Invited commentary on Schmidt, Liefooghe, and De Houwer (2020) An episodic model of task switching effects: erasing the homunculus from memory. Journal of Cognition.

A comparison of the efficacy of cleaning and disinfection methods in eliminating Salmonella spp. from commercial egg laying houses.

Effective terminal cleaning and disinfection (C&D) is regarded as a necessary step for the elimination of Salmonella spp. from laying houses. A total of 60 commercial laying houses that had housed laying flocks infected with Salmonella enterica serovar Enteritidis or Salmonella enterica serovar Typhimurium that were representative of all production systems (cage, barn, free-range) were intensively sampled immediately after C&D as well as in the follow-on flock. The procedures investigated were: (1) a compound disinfectant consisting of a mixture of formaldehyde, glutaraldehyde and quarternary ammonium applied at the recommended concentration; (2) a 10% (vol/vol) dilution of the standard 37% commercial formalin, applied by a contractor; and (3) other disinfection procedures selected and applied by the farmer. The recovery of Salmonella in the cleaned and disinfected houses was variable, with samples from floor and dropping boards/belts (cage houses) and scratching areas (non-cage houses) being the most likely to remain contaminated. In cage houses, the use of the 10% formalin dilution led to a statistically greater reduction in the sample prevalence than using any of the other C&D methods. A negative post-C&D result predicted clearance of Salmonella in 52% of cases, although the isolation of Salmonella from the houses immediately after C&D was not a perfect predictor of carry-over of infection.

Revisiting peak shift on an artificial dimension: Effects of stimulus variability on generalisation.

One of Mackintosh's many contributions to the comparative psychology of associative learning was in developing the distinction between the mental processes responsible for learning about features and learning about relations. His research on discrimination learning and generalisation served to highlight differences and commonalities in learning mechanisms across species and paradigms. In one such example, Wills and Mackintosh trained both pigeons and humans to discriminate between two categories of complex patterns comprising overlapping sets of abstract visual features. They demonstrated that pigeons and humans produced similar "peak-shifted" generalisation gradients when the proportion of shared features was systemically varied across a set of transfer stimuli, providing support for an elemental feature-based analysis of discrimination and generalisation. Here, we report a series of experiments inspired by this work, investigating the processes involved in post-discrimination generalisation in human category learning. We investigate how post-discrimination generalisation is affected by variability in the spatial arrangement and probability of occurrence of the visual features and develop an associative learning model that builds on Mackintosh's theoretical approach to elemental associative learning.

Instructed and Acquired Contingencies in Response-Inhibition Tasks.

Inhibitory control can be triggered directly via the retrieval of previously acquired stimulus-stop associations from memory. However, a recent study suggests that this item-specific stop learning may be mediated via expectancies of the contingencies in play (Best, Lawrence, Logan, McLaren, & Verbruggen, 2016). This could indicate that stimulus-stop learning also induces strategic proactive changes in performance. We further tested this hypothesis in the present study. In addition to measuring expectancies following task completion, we introduced a between-subjects expectancy manipulation in which one group of participants were informed about the stimulus-stop contingencies and another group did not receive any information about the stimulus-stop contingencies. Moreover, we combined this instruction manipulation with a distractor manipulation that was previously used to examine strategic proactive adjustments. We found that the stop-associated items slowed responding in both conditions. Furthermore, participants in both conditions generated expectancies following task completion that were consistent with the stimulus-stop contingencies. The distractor manipulation was ineffective. However, we found differences in the relationship between the expectancy ratings and task performance: in the instructed condition, the expectancies reliably correlated with the response slowing for the stop-associated items, whereas in the uninstructed condition we found no reliable correlation. These differences between the correlations were reliable, and our conclusions were further supported by Bayesian analyses. We conclude that stimulus-stop associations that are acquired either via task instructions or via task practice have similar effects on behaviour but could differ in how they elicit response slowing.

Pigeons' performance in a tracking change-signal procedure is consistent with the independent horse-race model.

In many cognitive tasks where humans are thought to rely on executive functioning, pigeons' behavior can be explained by associative processes. A key form of executive functioning is inhibiting prepotent responses, often investigated in humans by means of "Stop-Signal" or "Change-Signal" procedures. In these procedures, execution of a well-practiced ("Go") response to a stimulus is occasionally interrupted by a signal to withhold or alter the practiced response. Performance in such tasks is usually described by the "independent horse horse-race model." This model assumes that the processes that cause the Go and inhibitory responses occur independently; the process that finishes first determines the response observed. We further tested this model by training pigeons to track the circular movement of a colored patch around a touchscreen by pecking it; the spot occasionally deviated from its normal path (the Change signal). The pigeons had to inhibit the habitual movement of their heads to land a peck on the spot in its unexpected position. The key predictions of the independent horse-race model were confirmed in the pigeons' latency data. Thus, the independent race model can also successfully describe Stop-change performance of subjects that do not rely on executive control. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Investigation into the effectiveness of pooled fecal samples for detection of verocytotoxin-producing Escherichia coli O157 in cattle.

Verocytotoxin-producing Escherichia coli O157 (VTEC O157) may cause severe illness in people. Cattle are regarded as an important source of VTEC O157, and in an outbreak investigation, there is a necessity to establish whether or not the putative contact herd shares infection with the human case. The effectiveness of a herd investigation is impacted by the number of samples required, which will influence the time taken to collect samples and then process these in the laboratory. The objective of this study was to investigate the effectiveness of pooled sampling for detecting VTEC O157 in cattle herds in the United Kingdom. On farm 1, 150 individual fecal samples were collected during the course of a VTEC O157 outbreak investigation. One-gram and 10-g subsamples were tested from each individual sample. Once the culture results of the individual sample were known, pools comprising 5 and 10 individual samples were formed, with each pool containing a known number of positive samples. This data showed that the sensitivity of pooled sampling depended upon the proportion of positive samples in the pool. Further samples were collected from 2 more infected farms (2 and 3). Each individual sample was tested in duplicate. Pools of 5 feces were formed on-farm, and half the number of pooled feces were tested as individual feces. There was no significant difference between the number of cultures required for pooled sampling, as was the same for individual sampling, and therefore pooling did not improve the effectiveness of detection of VTEC O157.

Pigeons in control of their actions: Learning and performance in stop-signal and change-signal tasks.

In human participants, 2 paradigms commonly assumed to measure the executive-control processes involved in response inhibition are the stop-signal and change-signal tasks. There is, however, also considerable evidence that performance in these tasks can be mediated by associative processes. To assess which components of inhibitory response control might be associative, we developed analogues of these tasks for pigeons. We trained pigeons to peck quickly at 1 of 2 keys of different colors to obtain a food reward. On some trials, the rewarded key was replaced (after a varying interval) by a signal of a different color. For some birds, this was a change signal: pecking the signal had no effect, but pecking the usually unrewarded alternative key led to a reward, so the response had to be changed. For other birds, the change in color was a stop signal: pecking the alternative key remained ineffective, but pecking the signal now led to a timeout instead of the usual reward, so responses had to be withheld. Pigeons succeeded in both tasks, but performance declined with increasing signal delay. The details of performance in both tasks were consistent with the independent horse-race model of inhibitory control often applied to studies of human participants. This outcome further suggests that stop-signal tasks of the kind used here might not necessarily be suitable for assessing top-down executive-control processes in humans. (PsycINFO Database Record