Entire Test Session Research Articles

The Onset of Rapid-Guessing Behavior Over the Course of Testing Time: A Matter of Motivation and Cognitive Resources.

Digital tests make it possible to identify student effort by means of response times, specifically, unrealistically fast responses that are defined as rapid-guessing behavior (RGB). In this study, we used latent class and growth curve models to examine (1) how student characteristics (i.e., gender, school type, general cognitive abilities, and working-memory capacity) are related to the onset point of RGB and its development over the course of a test session (i.e., item positions). Further, we examined (2) the extent to which repeated ratings of task enjoyment (i.e., intercept and slope parameters) are related to the onset and the development of RGB over the course of the test. For this purpose, we analyzed data from N = 401 students from fifth and sixth grades in Germany (n = 247 academic track; n = 154 non-academic track). All participants solved 36 science items under low-stakes conditions and rated their current task enjoyment after each science item, constituting a micro-longitudinal design that allowed students' motivational state to be tracked over the entire test session. In addition, they worked on tests that assessed their general cognitive abilities and working-memory capacity. The results show that students' gender was not significantly related to RGB but that students' school type (which is known to be closely related to academic abilities in the German school system), general cognitive abilities, and their working-memory capacity were significant predictors of an early RGB onset and a stronger RGB increase across testing time. Students' initial rating of task enjoyment was associated with RGB, but only a decline in students' task enjoyment was predictive of earlier RGB onset. Overall, non-academic-school attendance was the most powerful predictor of RGB, together with students' working-memory capacity. The present findings add to the concern that there is an unfortunate relation between students' test-effort investment and their academic and general cognitive abilities. This challenges basic assumptions about motivation-filtering procedures and may threaten a valid interpretation of results from large-scale testing programs that rely on school-type comparisons.

Sleep deprivation precipitates the development of amphetamine-induced conditioned place preference in rats

Sleep deprivation (SD) and amphetamine use are commonly associated conditions. SD shares similar neurobiological effects with psychostimulants, playing an important role in drug addiction, especially through conditioning manipulations. The aim of the present study was to investigate the effects of SD on the development of amphetamine-induced conditioned place preference (CPP) in a protocol with a reduced number of conditioning sessions. Male adult Wistar rats were submitted to 4 conditioning sessions (2 sessions/day) in the CPP apparatus, half with saline (non-drug-paired compartment) and half with 2 mg/kg amphetamine (drug-paired compartment) after control (home-cage maintained) or SD (6 h gentle handling method) conditions. Control animals did not express a preference for the amphetamine-paired compartment, showing that 2 conditioning sessions with the drug were not sufficient to establish CPP. On the other hand, animals submitted to SD during the conditioning sessions expressed a preference for the amphetamine-paired compartment, which was maintained across the entire test session. SD precipitated the development of CPP to amphetamine, showing that lack of sleep can contribute to the establishment of a conditioning between the drug effect and environmental cues.

Window-based peak power model and Particle Swarm Optimization guided 3-dimensional bin packing for SoC test scheduling

This paper addresses the issue of power-aware test scheduling of cores in a System-on-Chip (SoC). While the existing approaches either use a fixed power value for the entire test session of a core or cycle-accurate power values, the proposed work divides the power profiles of cores into fixed-sized windows. This approach reduces the number of power values to be handled by the test scheduling algorithms while reducing the amount of pessimistic over-estimations of instantaneous power consumption. As a result, the power model can be integrated with more exhaustive meta-search techniques for generating power constrained test schedules. In this paper, the proposed power model has been integrated with a Particle Swarm Optimization (PSO) based 3-dimensional (3-D) bin packing technique to generate test schedules. Experimental results prove the quality of the approach to be high compared to the existing scheduling techniques.

Disrupted right ventricular force–frequency relationships in adults operated for ventricular septal defect as toddlers: Abnormal peak force predicts peak oxygen uptake during exercise

Recent studies have shown markedly reduced functional capacity in long-term survivors of ventricular septal defect (VSD), and in order to explore possible mechanisms, we performed non-invasive assessment of ventricular force–frequency relationships during exercise in adults operated for VSD in early childhood.We conducted a prospective study at a tertiary referral center. Patients (n=23) and healthy controls (n=20) underwent continuous Doppler-echocardiographic imaging during supine bicycle ergometry. The cycling workload was individually and manually incremented during the test session in response to heart rate. The heart was imaged in an apical 4-chamber view, and color-coded myocardial velocities were recorded. Post hoc, peak systolic velocity and isovolumetric acceleration (IVA) were blindly determined in the basal ventricular segments.VSD-operated patients differed markedly in all right ventricular endpoints compared with controls. IVA was lower prior to the test, 70±30cm/s2 vs. 150±60cm/s2 among controls, and during the entire test session ending at a heart rate of 160beats/min; 140±50cm/s2 vs. 300±30cm/s2, p<0.01 at both points. A similar pattern was revealed in terms of peak right ventricular systolic velocity. Left ventricular and septal measurements showed a similar, although less significant, tendency with a clearly lower left ventricular optimum heart rate among patients: 140beats/min vs. 154beats/min among controls. In the diseased cohort biventricular force–frequency relationships were directly correlated to peak oxygen uptake.VSD repair in early childhood is associated with disruption of the right ventricular force–frequency relationship, which may contribute to the previously observed reduction in functional capacity.

Range of motion (ROM) restriction influences quipazine-induced stepping behavior in postnatal day one and day ten rats

Previous research has shown that neonatal rats can adapt their stepping behavior in response to sensory feedback in real-time. The current study examined real-time and persistent effects of ROM (range of motion) restriction on stepping in P1 and P10 rats. On the day of testing, rat pups were suspended in a sling. After a 5-min baseline, they were treated with the serotonergic receptor agonist quipazine (3.0mg/kg) or saline (vehicle control). Half of the pups had a Plexiglas plate placed beneath them at 50% of limb length to induce a period of ROM restriction during stepping. The entire test session included a 5-min baseline, 15-min ROM restriction, and 15-min post-ROM restriction periods. Following treatment with quipazine, there was an increase in both fore- and hindlimb total movement and alternated steps in P1 and P10 pups. P10 pups also showed more synchronized steps than P1 pups. During the ROM restriction period, there was a suppression of forelimb movement and synchronized steps. We did not find evidence of persistent effects of ROM restriction on the amount of stepping. However, real-time and persistent changes in intralimb coordination occurred. Developmental differences also were seen in the time course of stepping between P1 and P10 pups, with P10 subjects showing show less stepping than younger pups. These results suggest that sensory feedback modulates locomotor activity during the period of development in which the neural mechanisms of locomotion are undergoing rapid development.

A new approach for detecting and analyzing cutaneous reflexes during locomotion

During human walking, due to their small amplitude, individual cutaneous reflex responses are difficult to detect in surface EMG recordings. In this study, we present a new algorithm to automatically detect individual cutaneous reflex responses and to extract their corresponding onset latency, amplitude, duration, and sign. To discriminate reflex responses from the intrinsic variability of the background EMG, each stimulated cycle is compared with 10 adjacent nonstimulated cycles, looking for consistent differences. In the first 200 ms after stimulation, reflex responses are detected when ≥ 9/10 of these differences are either positive or negative. This approach does not require amplitude thresholds or fixed time windows for reflex detection. To reduce false detections, a postprocessing step selects 50 nonstimulated cycles randomly, processes them through the algorithm as stimulated cycles, and establishes a minimal reflex duration criterion that it then used to validate the detected responses. Validated responses from an entire test session are then reported on a colormap (reflex activity map) from which specific responses can be identified and quantified. The new method was validated in ten participants, three cutaneous nerves, and two protocols (phase modulation and recruitment curves). Compared with the classical method, the new algorithm showed better performance in terms of detection accuracy, specificity, and reliability. Although tested here to evaluate cutaneous reflexes during human walking, the simplicity of this method is such that it could easily be used with other reflexes, signals, and preparations.

Possible entrainment of ghrelin to habitual meal patterns in humans

Ghrelin is reportedly a meal-initiation signal based on observations that concentrations increase before meals coincident with rising hunger. However, evidence that ghrelin peaks vary with feeding schedules suggests that it rises in anticipation of an expected meal, rather than eliciting feeding. To explore the entrainment of ghrelin profiles, this study investigated the association between varying habitual meal patterns and plasma ghrelin concentrations. Lean and obese adults following either a short intermeal interval (SII) pattern, with 2.5-3.5 h between their habitual breakfast and lunch times, or a long intermeal interval (LII) pattern, with 5.5-6.5 h between these eating occasions, participated. Food intake and appetite were recorded for 2 baseline days. On the subsequent test day, blood samples were collected over 8 h while participants ate a breakfast and lunch matched to their customary meals and pattern. Appetite ratings were obtained and ghrelin, insulin, glucose, and leptin concentrations were measured. Peak ghrelin concentrations differed significantly by group and occurred prior to each group's respective lunch time. Ghrelin concentrations directly correlated with subjective hunger. This association was stronger when hunger preceded ghrelin, a pattern inconsistent with ghrelin causing the hunger rise. Ghrelin concentrations were inversely correlated with insulin, and peak insulin concentrations preceded nadir ghrelin concentrations postprandially. Ghrelin concentrations periprandially, and over the entire test session, did not differ by meal group, likely because of similar intakes between groups. These data demonstrate that the timing of ghrelin peaks is related to habitual meal patterns and may rise in anticipation of eating rather than eliciting feeding.

The effects of nucleus accumbens dopamine depletions on continuously reinforced operant responding: Contrasts with the effects of extinction

Two experiments were undertaken to study the role of nucleus accumbens dopamine (DA) in instrumental lever pressing on a continuous reinforcement schedule (CRF). In the first experiment, the neurotoxic agent 6-hydroxydopamine was infused directly into the nucleus accumbens to investigate the effects of DA depletion on lever pressing performance. DA depletion had only a modest effect on the total number of lever presses, and there was a significant effect on total lever presses only on the first test day (third day postsurgery). Analyses also were performed on responding across the 45-min session by breaking down the session into three 15-min periods. During the test session on day 3 postsurgery, there was a significant group × time interaction, with DA-depleted rats showing a significant reduction in the numbers of responses in the first 15-min period, but no significant effects over the second or third 15-min period within the session. Although control rats showed a within-session decline in responding, the DA-depleted rats did not. In addition, analysis of interresponse times (IRTs) indicated that accumbens DA depletions produced a slowing of the local rate of responding as indicated by a significant decrease in high rate (i.e., short-duration IRT) responses and an increase in low rate (i.e., long-duration IRT) responses. In a second experiment, the effects of extinction on CRF performance were investigated. Unlike the effects of nucleus accumbens DA depletion, extinction produced lower levels of responding throughout the entire test session. In contrast to the effects of accumbens DA depletions, analysis of IRTs indicated that extinction produced a significant increase in high-rate responses (low IRTs), which is probably indicative of an extinction “burst.” These results indicate that accumbens DA depletions produce a response slowing that does not closely resemble the effects of extinction.

Large-Scale Assessment of Motor Activity in Rodents: Procedures for Routine Use in Toxicology Studies

An automated system for the routine large-scale assessment of motor activity in rats has been established in this laboratory for use in toxicity testing. This study was designed to evaluate the validity and sensitivity of motor activity measurements for routine use in toxicology studies. The effects of two known neurotoxins, acrylamide (ACR) and 3'3'-iminodipropionitrile (IDPN), were measured in rats using an automated photocell device in the context of a routine toxicology study. One hundred Sprague-Dawley rats (10/sex/group) were dosed with vehicle, ACR (10 and 30 mg/kg/day) or IDPN (50 or 125 mg/kg/day), by oral gavage 7 days per week for 5 weeks (except where otherwise indicated). Motor activity was measured in 5-min test sessions prior to initiating treatment, 6 and 24 h after the first dose, and weekly thereafter. Significant mortality occurred in high-dose ACR animals during Week 3. A 10-or 7-day recovery period was initiated after 20 or 22 daily doses for high-dose ACR and IDPN animals, respectively; after which, the high dose ACR and IDPN animals, respectively; after which, the high dose of ACE: was lowered to 20 mg/kg/day. Rapid habituation to the test environment occurred over the 5-imin testing sessions. Significant depressions in activity were observed in high-dose ACR males during Weeks 3 and 5 and in high-dose ACR females during Weeks 2-5. High-dose IDPN females showed no significant changes in activity. However, significant activity depressions were noted in males during weeks 1, 3, and 5. When depressions in activity occurred, they were apparent over the entire test session. The sensitivity of activity measures was sufficient to detect a 15% change in activity levels as compared with controls, with sufficient statistical power to meet regulatory requirements. Inclusion of motor activity assessments complements the additional parameters routinely measured in toxicology studies, augmenting hazard identification.

Ethanol and diazepam interactions on conflict behavior in rats

Twenty-four adult male rats trained on the Geller-Seifter conflict procedure received: 1.0, 2.0, or 4.0 mg/kg diazepam at 15 min, 0.25, 0.5, 1.0, 2.0, or 4.0 g/kg of ethanol (EtOH) at 30 min prior to the test session, or combinations of the same diazepam doses and 0.5 g/kg of EtOH. Ethanol administration produced a significant ( p<0.05) dose-related decrease in lever pressing during the periods prior to the introduction of the tone stimulus, compared to lever pressing during the corresponding control periods on the day prior to drug treatment. During the posttone periods 0.25 g/kg increased lever pressing ( p<0.05), while doses of EtOH from 0.5 to 4.0 g/kg resulted in significantly lower levels of lever pressing in periods following the discontinuation of the tone. In the presence of the conflict evoking tone stimulus, rats treated with 2.0 g/kg of EtOH increased their rate of lever pressing, while animals receiving the other EtOH doses exhibited lever pressing comparable to that observed during the corresponding control periods. Administration of EtOH had no effect on the number of reinforcements received during the entire test session, except for a significant ( p<0.05) reduction at the highest dose of 4.0 g/kg. Diazepam increased the number of reinforcements received during the entire test session as compared to those obtained during control sessions. Lever pressing was not affected by diazepam treatment during pretone or tone periods. During the posttone periods responses were significantly ( p<0.05) increased in rats receiving the lowest dose of 1.0 mg/kg of diazepam but the other doses were without effect. Combined exposure to 0.5 g/kg of EtOH and either 1.0, 2.0 or 4.0 mg/kg of diazepam resulted in significant ( p<0.05) reductions in lever pressing during the pretone periods compared to that observed with diazepam alone. The combination of EtOH with these doses of diazepam had no further effect on lever pressing during the posttone periods, or on the number of reinforcements received during the entire test session, compared to effects observed with diazepam alone. However, a significant ( p<0.01) interactive effect of EtOH and diazepam was observed for lever pressing in the presence of the conflict evoking tone stimulus. Exposure to 4.0 mg/kg of diazepam and 0.5 g/kg EtOH resulted in a marked increase in lever pressing in the presence of the tone stimulus, whereas either of these drug doses alone, as well as combinations of other diazepam doses and EtOH, had no effect on lever pressing during the tone periods. These results support an anxiolytic action of EtOH, defined as an increase in punished responding; as well as a sedative action, defined as a decrease in unpunished responding. In addition, diazepam potentiates anxiolytic and sedative actions of EtOH.

Judgments of aircraft noise in a traffic noise background

An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.