Modulation of an activity response with associative and nonassociative fear in the rat: A lighting differential influences the form of defensive behavior evoked after fear conditioning

Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion, the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive responses to the same stimulus.     

CS and US duration effects in one-trial simultaneous fear conditioning as assessed by conditioned suppression of licking in rats

In three experiments, rats received a single presentation of an auditory conditioned stimulus (CS) beginning simultaneously with an electric grid-shock unconditioned stimulus (US). Later, the CS was presented while the rats licked a drinking tube for water, and CS-elicited suppression of licking was taken as an index of the excitation conditioned to the CS. It was found that conditioning increased as a joint function of the duration of CS-US overlap and US duration. The evidence suggested that weak conditioning due to a brief CS-US overlap could be increased by extending the US beyond CS termination. Extending CS duration beyond US termination, however, did not strengthen conditioning; indeed, extending the CS 60 sec beyond US termination weakened conditioning significantly. It is suggested that these results shed light on a discrepancy in the recent literature on simultaneous conditioning.     

Mixed-methods exploration of students' motivation in using augmented reality in neuroanatomy education with prosected specimens

The use of augmented reality (AR) in teaching and studying neuroanatomy has been well researched. Previous research showed that AR-based learning of neuroanatomy has both alleviated cognitive load and was attractive to young learners. However, how the attractiveness of AR effects student motivation has not been discovered. Therefore, the motivational effects of AR were investigated in this research by the use of quantitative and qualitative methods. Motivation elicited by the GreyMapp-AR, an AR application, was investigated in medical and biomedical sciences students (n = 222; mean age: 19.7 ± 1.4 years) using the instructional measure of motivation survey (IMMS). Additional components (i.e., attention, relevance, confidence, and satisfaction) were also evaluated with motivation as measured by IMMS. Additionally, 19 students underwent audio-recorded individual interviews which were transcribed for qualitative analysis. Males regarded the relevance of AR significantly higher than females (P < 0.024). Appreciation of the GreyMapp-AR program was found to be significantly higher in students studying biomedical sciences as compared to students studying medicine (P < 0.011). Other components and scores did not show significant differences between student groups. Students expressed that AR was beneficial in increasing their motivation to study subcortical structures, and that AR could be helpful and motivating for preparing an anatomy examination. This study suggests that students are motivated to study neuroanatomy by the use of AR, although the components that make up their individual motivation can differ significantly between groups of students.     

Who can benefit from augmented reality in chemistry? Sex differences in solving stereochemistry problems using augmented reality

This paper is about augmented reality (AR) and its potentials to support students in handling scientific representations. For this purpose, first representations are examined from a science educational and instructional psychology perspective. After giving a short overview of AR in general and how it can be delineated from virtual reality (VR), potential advantages of an educational use of AR are outlined considering typical difficulties of students when learning with scientific representations. Since literature frequently reports sex differences in spatial abilities, this study focuses on potential differential effects in the use of AR depending on sex. Against this background, AR might be a tool which can help to compensate for disadvantages in spatial abilities. In order to investigate this question, chemistry students had to answer 20 items related to stereochemistry, a concept that places high demands on mental spatial rotation skills. While one half of the items had to be solved using two-dimensional (2D) ball-and-stick figures of molecules, the other half had to be answered with the help of AR representations. Due to the aforementioned sex differences regarding visuo-spatial abilities between males and females found in the literature, it is hypothesized that AR representations will support all students but females in particular by reducing cognitive load. If this assumption is correct, the AR items would have to be correctly solved by the students more often than the 2D items. The results of analyses of variance indeed reveal a significant effect of the sex variable dependent on the type of representation. In addition, a questionnaire was administered to survey the students’ attitudes towards learning with the AR app used.     

The role of trial tracking in rats’ working memory

The experiments reported in the present study tested whether decreasing intertrial intervals (ITIs) intensifies the disruptive effects of increasing retention intervals (RIs) in a delayed conditional discrimination by decreasing the animal’s trial tracking accuracy (Cohen & Armstrong, 1996; Cohen & Roberts, 1996). Rats responded on a fixed ratio (FR) 1 or fixed interval (FI) 10-sec reinforcement schedule at a second light or tone stimulus, S2, when the first light or tone stimulus, S1, had signaled an FI 10-sec or FR 1 schedule, respectively. RIs between S1 and S2 were increased from 3 to 24 sec and never exceeded ITIs that were reduced from 24 to 6 sec. For some rats, the trials were separated from each other by extending the lever at S1 and retracting it at the end of S2 (ITI lever-retracted group). For other, control rats, the lever remained extended throughout the session (lever-extended group, Experiment 1) or was extended and retracted with the onset and offset of each stimulus (RI/ITI lever-retracted group, Experiment 2). The rats under all trial conditions learned to delay leverpressing on the FI 10-sec schedule. Latency to begin leverpressing on the FI 10-sec schedule declined as RIs were increased, but this effect was attenuated in the ITI lever-retracted groups in both experiments, as would be predicted by thetrial tracking hypothesis. Decreasing ITIs from 24 to 6 sec intensified the disruptive effects of increasing RIs from 3 to 6 sec in the RI/ITI lever-retracted group (Experiment 2), as would be predicted by the trial tracking hypothesis.     

Concurrent observations of barpress suppression and freezing: Effects of CS modality and on-line vs. off-line training upon posttrial behavior

In a conditioned suppression study with rats, CS modality (light vs. noise) and type of conditioning (on-line vs. off-line training) were manipulated. All rats were then tested on-line with only half the test trials reinforced. Some results and conclusions were as follows: (1) During initial training, suppression following reinforced noise trials was moderately strong at first but weakened over days; for the light, it was weak from the start. It was suggested that this strong influence of CS modality might complicate interpretations of posttrial suppression as a measure of US effectiveness. (2) During testing, posttrial suppression and freezing were greater following non-reinforced trials than following reinforced trials (US-omission effect), and this effect was stronger for noise than for light. Since noise also produced more freezing than light, this result favors the hypothesis that the US-omission effect is due to persistent CS-elicited freezing that is un-disrupted by a shock US. (3) Although noise produced more freezing, both noise and light produced similar barpress suppression. This result is consistent with the suggestion that noise and light acquire equal associative strength but elicit different defensive behaviors.     

车灯线光源的计算

本文给出了“2002年全国大学生数学建模竞赛”中关于“车灯线光源”一题的解决方案。首先,通过同一球面上两球冠面积之比,解决了车灯中直射光与反射光的能量之比问题;其次,通过建立锥面方程,求出了线光源上任意一点发出的直射光在测试屏上的亮区,进而解决了整个线光源在测试屏上的直射光的亮区问题;最后,求出了线光源上任意一点发出的光线经过旋转抛物面上截线圆反射后,在测试屏上留下的反射光的亮区,然后使用数学软件绘出了整个线光源在测试屏上反射光的亮区。     

Additive summation by stimulus compounding irrespective of behavioral contrast during discrimination training: An investigation with positive reinforcement and avoidance schedules

The similarity in the discrimination training leading to behavioral contrast and that preceding tests producing response enhancement to combined discriminative stimuli suggested that the two phenomena might be related. This was investigated by determining if contrast indiscrimination training was necessary for this outcome of stimulus compounding. Responding to tone, light, and to the simultaneous absence of tone and light (T + L) was maintained during baseline training by food reinforcement in Experiment I and by shock avoidance in Experiment II. During subsequent discrimination training, responding was reduced in T + L by programming nonreinforcement in Experiment I and safety or response-punishment in Experiment II. In the first experiment, one rat exhibited positive behavioral contrast, i.e., tone and light rates increased while his T + L rate decreased. In Experiment II, rats punished in T + L showed contrast in tone and light, this being the first demonstration of punishment contrast on an avoidance baseline with rats. The discrimination acquisition data are discussed in the light of current explanations of contrast by Gamzu and Schwartz (1973) and Terrace (1972). During stimulus compounding tests, all subjects in both experiments emitted more responses to tone-plus-light than to tone or light (additive summation). An analysis of the terminal training baselines suggests that the factors producing these test results seem unrelated to whether or not contrast occurred during discrimination training. It was concluded that the stimulus compounding test reveals the operation of the terminal baseline response associations and reinforcement associations conditioned on these multicomponent free-operant schedules of reinforcement.

     

Specificity of cue to consequence in aversion learning in the rat: Control for US-induced differential orientations

In four experiments, each using a single conditioning trial, rats avoided a light more than a saccharin solution after these stimuli had been paired with footshock, whereas saccharin was avoided more than the light after these stimuli had been paired with lithium injection. The use of a single conditioning trial precludes possible US-induced differential orientations from influencing which stimuli will be associated on the conditioning trial. This cue-consequence specificity effect was obtained even when subjects conditioned with lithium received a non-contingent footshock prior to the test session, and when subjects conditioned with footshock received a noncontingent lithium injection before testing (Experiments 2–4). Weak aversions to the light in rats given a light-lithium pairing and noncontingent footshock and to the saccharin in subjects that received a saccharin-footshock pairing and noncontingent lithium administration were obtained in Experiment 2. However, these weak aversions were not obtained when subjects were given three nonreinforced exposures to the test chamber before the test session (Experiments 3 and 4). These results indicate that US-induced differential orientations do not mediate the cue-consequence effect in aversion learning.     

Postresponse exposure to warning signal in avoidance extinction

Delayed termination of the warning signal following extinction responses has been shown to facilitate extinction of discriminative avoidance. In order to determine the relative roles in extinction of delayed termination per se and postresponse exposure to the warning signal, which is necessarily confounded with delayed termination treatment, seven groups of rats were first trained on a one-way avoidance task in which a buzzer served as part of the warning-signal complex. Then, on nonshock extinction trials, the buzzer (a) terminated immediately with a response and was not reinstated in the postresponse interval, (b) terminated immediately with a response and was reinstated for a 5- or 10-sec period 5 or 15 sec following the response, or (c) terminated 5 or 10 sec following a response (delayed termination). Results indicated that exposure to the buzzer at postresponse intervals greater than 5 sec following responses was critically involved in reducing resistance to extinction. This finding supports a conditioned relief interpretation of the delayed warning signal termination effect and is consistent with the effect of response prevention techniques on extinction.     

One-trial excitatory backward conditioning as assessed by conditioned suppression of licking in rats: Concurrent observations of lick suppression and defensive behaviors

Twenty-eight male albino rats were given a single 4-sec 1-mA electric-grid-shock unconditioned stimulus (US). In the same session they received two 12-sec conditioned stimuli (CSs). One CS (explicitly unpaired) terminated 180 sec before the US began; the other (backward paired) began immediately after the US terminated. The CSs used were a 1000-Hz 85-dB tone and an 84-dB click; their roles were counterbalanced. Over the next 2 days, each CS was presented for 2 min while the rats drank from a water bottle. The backward-paired CS was found to suppress licking more than the explicitly unpaired CS. This suppression was accompanied by an increase in defensive behavior (freezing and freeze/nod) and by a decrease in other activity. The suppression did not seem to be due to a maintained or enhanced CS-orienting response reflex, nor could it be attributed to an adventitiously reinforced interfering operant. The results support the presumption made in previous reports that the lick suppression evoked by a backward CS reflected one-trial backward excitatory fear conditioning.     

Cognitive Strategies and Computer‐supported Learning Environments

ABSTRACT The purpose was to investigate cognitive strategies as differential determinants of co‐operative learning in peer‐based interaction environments. Computer‐supported Intentional Learning Environment (CSILE) was used. Participants were 51 students who studied in 3rd Grade classrooms. There were three individual working conditions: optimistic, pessimistic and defensive pessimistic. A total of 52 homogeneously or heterogeneously paired dyads on a measure of cognitive strategies were observed. Results show that individual working conditions are more productive than dyadic conditions. Specifically, optimistic strategy is related to better processing of ideas in databases than the other strategies. Moreover, heterogeneous dyads are not so beneficial configurations. Pessimistic strategy is not so debilitating a strategy as is usually assumed. This study shows that different cognitive strategies, and configurations of them, produce different kinds of results in the processing of ideas with computer‐supported learning environments.     

Blocking as a function of added cue intensity

Twelve rats were initially trained to leverpress for water in the presence of a tone. Responses in the absence of the tone were never reinforced. Following this pretraining, a novel light cue was simultaneously compounded with all presentations of the tone as a relevant but redundant predictor of reinforcement. For three different groups of subjects, the light cue was of either bright, moderate, or dim intensity. After compound training, all subjects experienced nonreinforced presentations of each of the two components of the compound. Results indicated that the relative degree of control exerted by the light over behavior increased with increases in light (added cue) intensity.     

Action research on a collegial model of peer observations

Observing peers for professional development is a familiar and valuable practice but not always favoured in many educational institutions. This small-scale action research (AR) was conducted in an institution where teachers are accustomed to regular peer observation, requiring each teacher to conduct peer observation and to reflect in their teachers’ portfolios. Conventionally, to fulfil the requirement each teacher finds a colleague to observe them either with or mostly without a certain focus. This study, however, employed action research methodology to inquire into a collegial peer observation model to improve this organisational practice. It aimed to promote mutual growth of the participating faculty members in an agreed area. Including the author, five faculty members, who are midcareer and experienced English language teachers, acted as members of the consultation group. In the AR project, appreciative inquiry was used when reflecting on the observed classes and during focus group interviews. As a result of this AR, at least two levels of knowledge were generated: first-person (author) and second-person (the team). The knowledge claim that this practitioner research constructed is ‘When small groups of teachers conduct peer observations focusing on a common concern, learning and collegial growth may increase.’ It is expected to lead to a third-person stage in the department and the academic community in general.     

Evaluating the integration of body donor imaging into anatomical dissection using augmented reality

Augmented reality (AR) has recently been utilized as an integrative teaching tool in medical curricula given its ability to view virtual objects while interacting with the physical environment. The evidence for AR in medical training, however, is limited. For this reason, the purpose of this mixed method study was to evaluate the implementation of overlaying donor-specific diagnostic imaging (DSDI) onto corresponding body donors in a fourth-year, dissection-based, medical elective course entitled anatomy for surgeons (AFS). Students registered in AFS course were separated into groups, receiving either DSDI displayed on Microsoft HoloLens AR head-mounted display (n = 12) or DSDI displayed on iPad (n = 15). To test for the change in spatial ability, students completed an anatomical mental rotation test (AMRT) prior to and following the AFS course. Students also participated in a focus group discussion and completed a survey at the end of AFS, analyzed through thematic triangulation and an unpaired, Mann Whitney U test respectively, both addressing dissection experience, DSDI relevancy to dissection, and use of AR in anatomical education. Although statistically significant differences were not found when comparing student group AMRT scores, survey and discussion data suggest that the HoloLens had improved the students' understanding of, and their spatial orientation of, anatomical relationships. Trunk dissection quality grades were significantly higher with students using the HoloLens. Although students mentioned difficulties with HoloLens software, with faculty assistance, training, and enhanced software development, there is potential for this AR tool to contribute to improved dissection quality and an immersive learning experience.     

Differential second-order aversive conditioning using contextual stimuli

Two experiments were conducted to determine if contextual stimuli used as S₂ in a higher-order differential conditioning procedure would control the performance of rats. Discrete stimuli were first paired with footshock in a separate training context. During second-order training, a shock-associated discrete stimulus was presented in one of two discriminable observation chambers. Over 4 days of training, subjects engaged in more freezing in the context associated with an excitatory discrete S₁, relative to a context in which no discrete stimulus, or a stimulus that had been explicitly unpaired with shock delivery, was presented. After acquisition of the second-order discrimination, animals were returned to the original training context where they received a “signaled inflation” treatment designed to change the current value of S₁, and the US. This postconditioning manipulation did not selectively affect performance of defensive freezing or conditional analgesia in S₂.     

Visual and social determinants of shock-elicited aggressive responding in rats

Light and dark reared, social and isolate housed, male Long-Evans hooded rats were tested in bright and dim light for aggressive response to footshock. Test lighting and socialization main effects were significant, with greater fighting in dim light than in bright light and greater fighting by isolates than by socially housed animals. Test lighting interacted with prior visual experience and socialization interacted with past and present illumination variables. The results suggest an inhibitory effect of test illumination dependent upon prior social and visual experience.     

The Effect of Stereoscopic Augmented Reality Visualization on Learning Anatomy and the Modifying Effect of Visual-Spatial Abilities: A Double-Center Randomized Controlled Trial

Monoscopically projected three-dimensional (3D) visualization technology may have significant disadvantages for students with lower visual-spatial abilities despite its overall effectiveness in teaching anatomy. Previous research suggests that stereopsis may facilitate a better comprehension of anatomical knowledge. This study evaluated the educational effectiveness of stereoscopic augmented reality (AR) visualization and the modifying effect of visual-spatial abilities on learning. In a double-center randomized controlled trial, first- and second-year (bio)medical undergraduates studied lower limb anatomy with stereoscopic 3D AR model (n = 20), monoscopic 3D desktop model (n = 20), or two-dimensional (2D) anatomical atlas (n = 18). Visual-spatial abilities were tested with Mental Rotation Test (MRT), Paper Folding Test (PFT), and Mechanical Reasoning (MR) Test. Anatomical knowledge was assessed by the validated 30-item paper posttest. The overall posttest scores in the stereoscopic 3D AR group (47.8%) were similar to those in the monoscopic 3D desktop group (38.5%; P = 0.240) and the 2D anatomical atlas group (50.9%; P = 1.00). When stratified by visual-spatial abilities test scores, students with lower MRT scores achieved higher posttest scores in the stereoscopic 3D AR group (49.2%) as compared to the monoscopic 3D desktop group (33.4%; P = 0.015) and similar to the scores in the 2D group (46.4%; P = 0.99). Participants with higher MRT scores performed equally well in all conditions. It is instrumental to consider an aptitude–treatment interaction caused by visual-spatial abilities when designing research into 3D learning. Further research is needed to identify contributing features and the most effective way of introducing this technology into current educational programs.     

The contribution of visual and inertial mechanisms to navigation in total darkness

Rats were trained in the Morris water maze to reach a platform in darkness after they had been provided with some information on their initial location. They were given trials with (1) the light on (light condition) and (2) light followed by darkness (dark condition). In this latter condition, the dark period was preceded by either a brief (short group) or a long (long group) initial light period. Although the rats in the short group first oriented accurately toward the platform, their trajectory rapidly deviated in darkness. In contrast, the rats in the long group were able to navigate accurately over a longer distance, but finally also deviated. In transfer trials, the rats in the short group were less accurate than the rats in the long group in the dark; however, both groups performed well in light. This suggests that navigation in darkness depends not only on the use of recent visual and locomotor memory but also on the activation of an inertia-based navigation process.     

How does the ecological foraging behavior of desert kangaroo rats (Dipodomys deserti) relate to their behavior on radial mazes?

Experiment 1 showed that laboratory-reared desert kangaroo rats, like domestic Norway rats, efficiently search for food on a radial arm maze (RAM) by avoiding revisiting arms within a trial. By placing an RAM on the floor so the animals could approach food from any direction, Experiment 2 tested whether efficient search by kangaroo rats was based on tactics of distance minimizing, central-place foraging, trail following, or meandering. In contrast to the dominant trail-following tactic of domestic Norway rats (Hoffman, Timberlake, Leffel, & Gont, 1999), kangaroo rats tended to distance minimize, whether maze arms were present or not. Experiment 3 indicated that kangaroo rats treated a floor configuration of eight food cups as twopatches of four, based on beeline travel between patches and meandering within them. We conclude that similar performance in an elevated RAM by different species can be based on different tactics, and we suggest that a laboratory apparatus can be used to cast light on niche-related mechanisms.