Acquisition Of Discrimination Research Articles

Effects of Feedback Modality Upon the Acquisition and Transfer of a Second-Order Conditional Discrimination

Dos grupos de participantes fueron expuestos a una tarea de igualación de la muestra de segundo orden y varias pruebas de transferencia con estímulos y relaciones de igualación familiares y novedosos. Las respuestas de igualación correctas e incorrectas produjeron retroalimentación en modalidad visual, escrita o auditiva para ambos grupos. Cada modalidad de retroalimentación se correlacionó con un estímulo de muestra particular para el grupo experimental, mientras que para el grupo control las modalidades de retroalimentación no se correlacionaron con los estímulos de muestra. La retroalimentación auditiva produjo ejecuciones bajas sólo en el grupo control. En general, la velocidad de adquisición durante el entrenamiento y el porcentaje de respuestas correctas en las pruebas de transferencia fueron mayores para el grupo experimental que para el grupo control. En el caso del grupo experimental, el desempeño en las pruebas de transferencia no se vio afectado por el carácter familiar o novedoso de los estímulos ni por la relación de igualación agregada. Los resultados sugieren la aparición de un efecto de consecuencias diferenciales que parece ser inmune al comportamiento lingüístico que presumiblemente medió el desempeño en las pruebas.

A comparison of stimulus fading and stimulus shaping on perceptual category learning.

Errorless learning strategies such as stimulus fading and stimulus shaping are commonly used to teach complex skills like categorisation and concept formation. Despite widespread use, very few studies have explored the comparative effectiveness of these procedures in well-controlled analyses. The vast majority of existing studies have been undertaken with clinical populations and have involved small numbers of participants (e.g., Single-case designs). The present study sought to compare stimulus fading, stimulus shaping, and trial-and-error learning in a perceptual categorisation task. In Experiment 1, we found robust benefits of stimulus shaping when compared to stimulus fading or trial-and-error learning on measures of initial acquisition of discrimination and one measure of stimulus generalisation. These findings were replicated in a second experiment in which the dimension of fading/shaping was changed from a modification of the comparison stimuli (S-) to a modification of the target stimulus (S +). We discuss the implications of our findings for the selection of errorless learning strategies in clinical settings.

Discrimination and equivalence class formation in adults using non-differential and differential consequences

ABSTRACT The purpose of the current study was to (1) compare the acquisition of baseline conditional discriminations in younger and older adults, (2) study the effect of the differential outcome procedure (DOP) on the establishment of baseline conditional discriminations, and (3) compare equivalence class formation in younger and older adults. Twenty-four participants, 12 younger adults (20–30 years old) and 12 older adults (67+ years old), participated in the study. In the conditional discrimination training, we gave the participants a break following 180 training trials, and the experimenter evaluated their progress. Participants with overall 50% correct responses or more after those 180 trials continued with the study as planned, with baseline conditional discrimination presented in accordance with the one-to-many (OTM) training structure and serialized training, followed by thinning of programmed consequences across training blocks before a test for the emergence of equivalence classes. If a participant was still training AB-conditional discriminations when the break was presented, with overall correct responses below 50% correct, the participant was exposed to a DOP to evaluate whether such a procedure may facilitate the establishment of the baseline conditional discrimination. Five participants in the older adult group received additional DOP training trials. The results show that two out of the five participants receiving DOP training established the AB baseline conditional discrimination. Neither of those responded in accordance with stimulus equivalence. Two out of the other seven participants in the older adults group and six out of 12 participants in the younger group formed equivalence classes.

Acute stress persistently alters instrumental motivation without affecting appetitive Pavlovian conditioning, extinction, or contextual renewal

In two experiments, we adapted the stress-enhanced fear learning approach to evaluate the persistent effects of acute stress on appetitive learning and motivation in adult male Long Evans rats. In Experiment 1, we found that exposure to a battery of footshocks in one context had no effect on the acquisition, extinction, or contextual renewal of an appetitive Pavlovian discrimination in different contexts. However, when rats were subsequently trained to respond on a progressive ratio instrumental schedule, rats with a history of shock showed lower response rates and progressive ratio break points. Extinction of the shock-associated context had little effect on progressive ratio responding. In Experiment 2, we replicated this instrumental responding deficit with a continuous reinforcement schedule when the Pavlovian phases did not intervene in the time between shock and instrumental testing. Our findings here demonstrate that highly stressful acute experiences produce long-lasting deficits in instrumental motivation for food in male rats.

Combining robust level extraction and unsupervised adaptive classification for high-accuracy fNIRS-BCI: An evidence on single-trial differentiation between mentally arithmetic- and singing-tasks.

Functional near-infrared spectroscopy (fNIRS) is a safe and non-invasive optical imaging technique that is being increasingly used in brain-computer interfaces (BCIs) to recognize mental tasks. Unlike electroencephalography (EEG) which directly measures neural activation, fNIRS signals reflect neurovascular-coupling inducing hemodynamic response that can be slow in time and varying in the pattern. The established classifiers extend the EEG-ones by mostly employing the feature based supervised models such as the support vector machine (SVM) and linear discriminant analysis (LDA), and fail to timely characterize the level-sensitive hemodynamic pattern. A dedicated classifier is desired for intentional activity recognition of fNIRS-BCI, including the adaptive acquisition of response relevant features and accurate discrimination of implied ideas. To this end, we herein propose a specifically-designed joint adaptive classification method that combines a Kalman filtering (KF) for robust level extraction and an adaptive Gaussian mixture model (a-GMM) for enhanced pattern recognition. The simulative investigations and paradigm experiments have shown that the proposed KF/a-GMM classification method can effectively track the random variations of task-evoked brain activation patterns, and improve the accuracy of single-trial classification task of mental arithmetic vs. mental singing, as compared to the conventional methods, e.g., those that employ combinations of the band-pass filtering (BPF) based feature extractors (mean, slope, and variance, etc.) and the classical recognizers (GMM, SVM, and LDA). The proposed approach paves a promising way for developing the real-time fNIRS-BCI technique.

Anterior thalamic nuclei: A critical substrate for non-spatial paired-associate memory in rats.

Injury or dysfunction in the anterior thalamic nuclei (ATN) may be the key contributory factor in many instances of diencephalic amnesia. Experimental ATN lesions impair spatial memory and temporal discriminations, but there is only limited support for a more general role in non-spatial memory. To extend evidence on the effects of ATN lesions, we examined the acquisition of biconditional associations between odour and object pairings presented in a runway, either with or without a temporal gap between these items. Intact adult male rats acquired both the no-trace and 10-s trace versions of this non-spatial task. Intact rats trained in the trace version showed elevated Zif268 activation in the dorsal CA1 of the hippocampus, suggesting that the temporal component recruited additional neural processing. ATN lesions completely blocked acquisition on both versions of this association-memory task. This deficit was not due to poor inhibition to non-rewarded cues or impaired sensory processing, because rats with ATN lesions were unimpaired in the acquisition of simple odour discriminations and simple object discriminations using similar task demands in the same apparatus. This evidence challenges the view that impairments in arbitrary paired-associate learning after ATN lesions require the use of multimodal spatial stimuli. It suggests that diencephalic amnesia associated with the ATN stems from degraded attention to stimulus-stimulus associations and their representation across a distributed memory system.

Potential trade-off between olfactory and visual discrimination learning in common marmosets (Callithrix jacchus): Implications for the assessment of age-related cognitive decline.

Olfactory dysfunction has been identified as an early biomarker for dementia risk but has rarely been assessed in nonhuman primate models of human aging. To better characterize common marmosets as such models, we assessed olfactory discrimination performance in a sample of 10 animals (5 females), aged 2.5-8.9 years old. The monkeys were proficient in the discrimination and reversal of visual stimuli but naïve to odor stimuli. For olfactory discrimination, the monkeys performed a series of six discriminations of increasing difficulty between two odor stimuli. We found no evidence for an age-related decline as both young and older individuals were able to perform the discriminations in roughly the same number of trials. In addition, the older monkeys had faster responses than the younger animals. However, we noted that when adjusted for age, the speed of acquisition of the first discrimination in the olfactory modality was inversely correlated to the speed of acquisition of their first discrimination of two visual stimuli months earlier. These results suggest that marmosets may compensate for sensory deficits in one modality with higher sensory performance in another. These data have broad implications for the assessment of age-related cognitive decline and the categorization of animals as impaired or nonimpaired.

Flexible learning of matching and mismatching by pigeons

When pigeons learn a conditional discrimination in which a sample stimulus indicates which of two comparison stimuli is correct Skinner (1950) proposed that they learn a chain involving the sample, the correct comparison stimulus, and the reinforcer. This implies that they do not learn to reject the incorrect comparison stimulus and the sameness relation between the sample and the correct or the incorrect comparison stimulus plays little role in learning. There is, however, considerable evidence that learning to match or mismatch the sample can transfer to novel stimuli. But there is little evidence that the sameness relation facilitates acquisition. In the present research, pigeons were trained on two 0-s delay conditional discriminations: two matching tasks, two mismatching tasks, or one of each. No differences were found in acquisition, suggesting that consistent matching or mismatching does not facilitate acquisition of conditional discriminations. In testing, when either the correct or the incorrect comparison stimulus in each discrimination was replaced with one of the stimuli from the other task, results suggested that when learning both tasks, the pigeons in all three groups had learned both to select the correct stimulus and to reject the incorrect stimulus. It appears that the pigeons may have had learned the tasks based on sample/comparison-stimulus configurations with the sample serving as an occasion setter.

Sphingolipids and DHA Improve Cognitive Deficits in Aged Beagle Dogs

Canine cognitive dysfunction syndrome (CDS) is a disorder found in senior dogs that is typically defined by the development of specific behavioral signs which are attributed to pathological brain aging and no other medical causes. One way of objectively characterizing CDS is with the use of validated neuropsychological test batteries in aged Beagle dogs, which are a natural model of this condition. This study used a series of neuropsychological tests to evaluate the effectiveness of supplementation with a novel lipid extract containing porcine brain-derived sphingolipids (Biosfeen®) and docosahexaenoic acid (DHA) for attenuating cognitive deficits in aged Beagles. Two groups (n = 12), balanced for baseline cognitive test performance, received a daily oral dose of either test supplement, or placebo over a 6-month treatment phase. Cognitive function was evaluated using the following tasks: delayed non-matching to position (DNMP), selective attention, discrimination learning retention, discrimination reversal learning, and spatial discrimination acquisition and reversal learning. The effect of the supplement on brain metabolism using magnetic resonance spectroscopy (MRS) was also examined. A significant decline (p = 0.02) in DNMP performance was seen in placebo-treated dogs, but not in dogs receiving the supplement, suggesting attenuation of working memory performance decline. Compared to placebo, the supplemented group also demonstrated significantly improved (p = 0.01) performance on the most difficult pattern of the spatial discrimination task and on reversal learning of the same pattern (p = 0.01), potentially reflecting improved spatial recognition and executive function, respectively. MRS revealed a significant increase (p = 0.048) in frontal lobe glutamate and glutamine in the treatment group compared to placebo, indicating a physiological change which may be attributed to the supplement. Decreased levels of glutamate and glutamine have been correlated with cognitive decline, suggesting the observed increase in these metabolites might be linked to the positive cognitive effects found in the present study. Results of this study suggest the novel lipid extract may be beneficial for counteracting age-dependent deficits in Beagle dogs and supports further investigation into its use for treatment of CDS. Additionally, due to parallels between canine and human aging, these results might also have applicability for the use of the supplement in human cognitive health.

Does clozapine affect the discriminative stimulus effects of food deprivation in rats trained to discriminate between 2 and 22 hours food deprivation?

In humans, weight gain is a side effect of several atypical antipsychotics. Previous research with rodents indicates clozapine may increase food consumption for the first 2‐4 hours after injection (Antelman et al. 1977; Benvenga & Leander 1997; Lee & Clifton 2002) as well as increase motivation to acquire food under a progressive ratio schedule (Abela et al. 2020; Loh et al. 1992; Mobini et al. 2000). In other studies, however, clozapine has been shown to reduce response rates in lever pressing operant procedures (Ford et al., 1997; Kaempf & Porter, 1997; Varvel et al., 2002; Wiley et al., 1994; Abela 2020) and decrease food intake in rodents (Baptista et al., 1993). The current study investigated if clozapine would affect the discriminative stimulus effects of food deprivation. Male, Sprague‐Dawley rats (n = 11) were trained to discriminate 22 hrs of food deprivation from 2 hrs of food deprivation in a two‐lever, operant choice task. Rats were trained to respond on the right lever after 2 hrs of food deprivation to earn a 45 mg food pellet under an FR 15 schedule. Left lever presses were punished with 8 seconds of darkness. Under 22 hr deprivation conditions, the contingencies were reversed (left lever presses were reinforced with food delivery and right lever presses resulted in 8 seconds of darkness). Training sessions lasted until subjects earned 10 reinforcers or 15 minutes elapsed. Acquisition of discrimination was defined as 80% or greater condition appropriate responding both before the first reinforcer was earned and for the entire session for 8 out of 10 consecutive days. After acquiring the discrimination, subjects were food deprived for 2 or 22 hrs and administered clozapine (1.0 ‐ 5.6 mg/kg, s.c.). or vehicle (30% DMSO; 1.0 ml/kg, s.c.). During test sessions, responses toward either lever were reinforced under the FR 15. The session lasted until subjects earned 5 reinforcers or 5 minutes elapsed, whichever occurred first. The discriminative stimulus effects of food deprivation and response rates were assessed every 15 min for the succeeding 2 hrs. After test sessions, each subjects’ food intake was recorded for 1 hour. Clozapine had no effect on the discriminative stimulus effects of 2 hr deprivation, however, clozapine (1.0 ‐ 5.6 mg/kg) significantly decreased response rates. After 22 hrs food deprivation, clozapine (1.0 ‐ 5.6 mg/kg) significantly decreased % 22 hr deprivation‐appropriate responding. Response rates were significantly increased by 1.0 mg/kg clozapine, whereas response rates were decreased by 5.6 mg/kg clozapine compared to rates of responding following 30% DMSO. Clozapine (3.2 ‐ 5.6 mg/kg) decreased food intake in rats under both food deprivation conditions. These data provide further support for the notion that clozapine decreases feeding‐related behaviors in rats.

Impaired discrimination of a subanesthetic dose of ketamine in a maternal immune activation model of schizophrenia risk.

Animal models of psychiatric diseases suffer from a lack of reliable methods for accurate assessment of subjective internal states in nonhumans. This gap makes translation of results from animal models to patients particularly challenging. Here, we used the drug-discrimination paradigm to allow rats that model a risk factor for schizophrenia (maternal immune activation, MIA) to report on the subjective internal state produced by a subanesthetic dose of the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine. The MIA rats' discrimination of ketamine was impaired relative to controls, both in the total number of rats that acquired and the asymptotic level of discrimination accuracy. This deficit was not due to a general inability to learn to discriminate an internal drug cue or internal state generally, as MIA rats were unimpaired in the learning and acquisition of a morphine drug discrimination and were as sensitive to the internal state of satiety as controls. Furthermore, the deficit was not due to a decreased sensitivity to the physiological effects of ketamine, as MIA rats showed increased ketamine-induced locomotor activity. Finally, impaired discrimination of ketamine was only seen at subanesthetic doses which functionally correspond to psychotomimetic doses in humans. These data link changes in NMDA responses to the MIA model. Furthermore, they confirm the utility of the drug-discrimination paradigm for future inquiries into the subjective internal state produced in models of schizophrenia and other developmental diseases.

Dissociative Effects of Neuropeptide S Receptor Deficiency and Nasal Neuropeptide S Administration on T-Maze Discrimination and Reversal Learning.

Cognitive flexibility refers to the ability to modify learned behavior in response to changes in the environment. In laboratory rodents, cognitive flexibility can be assessed in reversal learning, i.e., the change of contingencies, for example in T-maze discrimination learning. The present study investigated the role of the neuropeptide S (NPS) system in cognitive flexibility. In the first experiment, mice deficient of NPS receptors (NPSR) were tested in T-maze discrimination and reversal learning. In the second experiment, C57BL/6J mice were tested in the T-maze after nasal administration of NPS. Finally, the effect of nasal NPS on locomotor activity was evaluated. NPSR deficiency positively affected the acquisition of T-maze discrimination but had no effects on reversal learning. Nasal NPS administration facilitated reversal learning and supported an allocentric learning strategy without affecting acquisition of the task or locomotor activity. Taken together, the present data show that the NPS system is able to modulate both acquisition of T-maze discrimination and its reversal learning. However, NPSR deficiency only improved discrimination learning, while nasal NPS administration only improved reversal learning, i.e., cognitive flexibility. These effects, which at first glance appear to be contradictory, could be due to the different roles of the NPS system in the brain regions that are important for learning and cognitive flexibility.

Locus Coeruleus Activation Patterns Differentially Modulate Odor Discrimination Learning and Odor Valence in Rats.

ABSTRACTThe locus coeruleus (LC) produces phasic and tonic firing patterns that are theorized to have distinct functional consequences. However, how different firing modes affect learning and valence encoding of sensory information are unknown. Here, we show bilateral optogenetic activation of rat LC neurons using 10-Hz phasic trains of either 300 ms or 10 s accelerated acquisition of a similar odor discrimination. Similar odor discrimination learning was impaired by noradrenergic blockade in the piriform cortex (PC). However, 10-Hz phasic light-mediated learning facilitation was prevented by a dopaminergic antagonist in the PC, or by ventral tegmental area (VTA) silencing with lidocaine, suggesting a LC–VTA–PC dopamine circuitry involvement. Ten-hertz tonic stimulation did not alter odor discrimination acquisition, and was ineffective in activating VTA DA neurons. For valence encoding, tonic stimulation at 25 Hz induced conditioned odor aversion, whereas 10-Hz phasic stimulations produced an odor preference. Both conditionings were prevented by noradrenergic blockade in the basolateral amygdala (BLA). Cholera Toxin B retro-labeling showed larger engagement of nucleus accumbens-projecting neurons in the BLA with 10-Hz phasic activation, and larger engagement of central amygdala projecting cells with 25-Hz tonic light. These outcomes argue that the LC activation patterns differentially influence both target networks and behavior.

Comparison of sounds and words as sample stimuli for discrimination training.

A portion of children diagnosed with autism spectrum disorder (ASD) have difficulty acquiring conditional discrimination. However, previous researchers suggested that the discrimination of nonverbal auditory stimuli may be acquired more efficiently (Eikeseth & Hayward, 2009; Uwer, et al., 2002). For example, a child may learn to touch a picture of a piano after hearing the musical instrument more quickly than when the auditory stimulus is the spoken word "piano." The purpose of the present study was to extend previous research by assessing the acquisition of conditional discriminations with sample stimuli presented as either automated spoken words or high- and low-disparity nonverbal auditory stimuli (i.e., environmental sounds). Conditional discriminations with high-disparity environmental sounds as sample stimuli were acquired rather than or more efficiently than those trained with low-disparity environmental sounds and words as sample stimuli.

When do errors in reinforcer delivery affect learning? A parametric analysis of treatment integrity.

Treatment integrity is the extent to which components of an intervention are implemented as intended (Gresham, 1989). Recent behavior-analytic literature has begun to evaluate the effects of reduced-treatment integrity on the efficacy and efficiency of skill-acquisition interventions. This study extended the current literature on the effects of errors of omission and commission of reinforcer delivery by replicating and extending Hirst and DiGennaro Reed (2015). Using a randomized-control group design, we compared undergraduate student participants' acquisition of conditional discriminations in a parametric analysis of different error values. A computer program erred in reinforcer delivery on 0%, 5%, 10%, 15%, 20%, 25% and 50% of trials. The purpose of the current study was to identify which levels of reduced integrity slowed or prevented acquisition. Our data replicated the findings of Hirst and DiGennaro Reed, and extended parametric analyses by identifying that errors in reinforcer delivery occurring on 15% or fewer trials (i.e., 85% integrity) were unlikely to prevent participants' responding from meeting the mastery criterion. These results could inform future research on how treatment-integrity errors change behavior-analytic procedures and the effects on skill acquisition for consumers of applied behavior analysis.

Discrimination of Driver Fatigue Based on Distortion Energy Density Theory and Multiple Physiological Signals

Driver fatigue is an important contributor to traffic accidents, and driver fatigue is significant for the safety of people’s lives. Aiming to prevent traffic accidents caused by driver fatigue, a series of real driving experiments was carried out in the present work. First, based on an analysis with respect to distortion energy density (DED) theory and the experimental results, the upper trapezius at 6th neck vertebrae is more sensitive to driver fatigue and easier to fatigue than that at 7th neck vertebrae in a real driving. And then 2 cm from the 6th vertebrae on both sides were selected as the locations of data acquisition for electromyography (EMG) signal. The experimental results show that the approximate entropy (ApEn) from the electroencephalography (EEG), EMG, and respiration (RESP) signals decreases with increasing driving time, indicating that the degree of fatigue increases. After approximately 90 min, the rate of decrease in ApEn becomes slow, indicating deeper driver fatigue. According to three-D analysis, principal component analysis, and fuzzy C-means clustering analysis, the EEG-EMG combination effectively reflects the state of drivers. Finally, the ApEns from EEG and EMG were selected as independent variables, and a discriminant model of driver fatigue based on Mahalanobis distance theory was built. The accuracy of the model is up to 90.92% by 10-fold cross validation. The reasons for the high accuracy are the reasonable selection of the locations of EMG data acquisition and better degree of discrimination of EEG and EMG. The main contributions of this study are to provide a theoretical foundation for establishing internationally recognized standard locations for neck EMG data acquisition, and to provide a feasible method for discriminating driver fatigue in real driving tasks.

Equivalence Class Formation in Individuals With Autism: Predictions From ABLA-R Levels.

Children who are diagnosed with autism spectrum disorder (ASD) often fail to show equivalence class formation. This may be related to their difficulty in learning the programmed baseline conditional discriminations. The present study investigated equivalence class formation after training visual identity-matching performance with auditory class-specific consequences in 6 individuals who were diagnosed with ASD and who achieved different levels (Levels 4, 5, and 6) on the Assessment of Basic Learning Abilities-Revised (ABLA-R). The potentially emergent relations were all arbitrary (relations between completely dissimilar stimuli): visual-visual (AB and BA) and auditory-visual (SA and SB). None of the participants who achieved ABLA-R Level 4 or 5 responded in accord with equivalence class formation. They did not present any emergent arbitrary conditional relations (either visual-visual relations or auditory-visual relations). Only participants who achieved ABLA-R Level 6 demonstrated equivalence class formation. These findings are consistent with the predictive ability of the ABLA-R with regard to the acquisition of discriminations and to the emergence of the same type of conditional relations and the same hierarchy of complexity.

Blockade of the M1 muscarinic acetylcholine receptors impairs eyeblink serial feature-positive discrimination learning in mice.

The serial feature-positive discrimination task requires the subjects to respond differentially to the identical stimulus depending on the temporal context given by a preceding cue stimulus. In the present study, we examined the involvement of the M1 muscarinic acetylcholine receptors using a selective M1 antagonist VU0255035 in the serial feature-positive discrimination task of eyeblink conditioning in mice. In this task, mice received a 2-s light stimulus as the conditional cue 5 or 6 s before the presentation of a 350-ms tone conditioned stimulus (CS) paired with a 100-ms peri-orbital electrical shock (cued trials), while they did not receive the cue before the presentation of the CS alone (non-cued trials). Each day mice randomly received 30 cued and 30 non-cued trials. We found that VU0255035 impaired acquisition of the conditional discrimination as well as the overall acquisition of the conditioned response (CR) and diminished the difference in onset latency of the CR between the cued and non-cued trials. VU0255035 administration to the control mice after sufficient learning did not impair the pre-acquired conditional discrimination or the CR expression itself. These effects of VU0255035 were almost similar to those with the scopolamine in our previous study, suggesting that among the several types of muscarinic acetylcholine receptors, the M1 receptors may play an important role in the acquisition of the conditional discrimination memory but not in mediating the discrimination itself after the memory had formed in the eyeblink serial feature-positive discrimination learning.

Sex chromosome complement affects multiple aspects of reversal-learning task performance in mice.

Determining the mechanisms by which the sex-chromosome complement (SCC) affects learning, attention, and impulsivity has implications for observed sex differences in prevalence, severity, and prognosis of psychiatric/neurodevelopmental disorders and syndromes associated with sex-chromosome aneuploidy. Here, Four Core Genotypes (FCG) mice were evaluated in order to assess the separable and/or interacting effects of gonads (testes vs. ovaries) and their secretions and/or SCC (XX vs. XY) acting via non-gonadal mechanisms on behavior. We tested FCG mice on a reversal-learning task that enables the quantification of aspects of learning, attention and impulsivity. Across testing phases (involving the initial acquisition of a spatial discrimination and subsequent reversal learning), overall error rate was larger in XY compared with XX mice. Although XX and XY groups did not differ in the total number of trials required in order to reach a preset performance criterion, analyses of reversal error types showed more perseverative errors in XY than XX mice, with no difference in regressive errors. Additionally, prepotent-response latencies during the reversal phase were shorter in XY males, as compared with both XX gonadal males and females of either SCC, and failures to sustain the observing response were more frequent in XY mice than XX mice during the acquisition phase. These results indicate that SCC affects the characteristic pattern of response selection during acquisition and reversal performance without affecting the overall learning rate. More broadly, these results show direct effects of the SCC on cognitive processes that are relevant to psychiatric/neurodevelopmental disorders and syndromes associated with sex-chromosome aneuploidies.

Preliminary evidence suggests that functional reinforcement contingencies may result in more rapid acquisition of initial auditory-visual discriminations for some individuals with autism spectrum disorder1

Q(1) Which is more effective at establishing initial auditory-visual discriminations for individuals with autism spectrum disorder: functional reinforcement or arbitrary reinforcement contingencies...