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operant conditioning [keywords]
- Validation of operant social motivation paradigms using BTBR T+tf/J and C57BL/6J inbred mouse strains. [Journal Article]
- Brain Behav 2014 Sep; 4(5):754-64.
As purported causal factors are identified for autism spectrum disorder (ASD), new assays are needed to better phenotype animal models designed to explore these factors. With recent evidence suggesting that deficits in social motivation are at the core of ASD behavior, the development of quantitative measures of social motivation is particularly important. The goal of our study was to develop and validate novel assays to quantitatively measure social motivation in mice.In order to test the validity of our paradigms, we compared the BTBR strain, with documented social deficits, to the prosocial C57BL/6J strain. Two novel conditioning paradigms were developed that allowed the test mouse to control access to a social partner. In the social motivation task, the test mice lever pressed for a social reward. The reward contingency was set on a progressive ratio of reinforcement and the number of lever presses achieved in the final trial of a testing session (breakpoint) was used as an index of social motivation. In the valence comparison task, motivation for a food reward was compared to a social reward. We also explored activity, social affiliation, and preference for social novelty through a series of tasks using an ANY-Maze video-tracking system in an open-field arena.BTBR mice had significantly lower breakpoints in the social motivation paradigm than C57BL/6J mice. However, the valence comparison task revealed that BTBR mice also made significantly fewer lever presses for a food reward.The results of the conditioning paradigms suggest that the BTBR strain has an overall deficit in motivated behavior. Furthermore, the results of the open-field observations may suggest that social differences in the BTBR strain are anxiety induced.
- Enhanced discriminative fear learning of phobia-irrelevant stimuli in spider-fearful individuals. [Journal Article]
- Front Behav Neurosci 2014.:328.
Avoidance is considered as a central hallmark of all anxiety disorders. The acquisition and expression of avoidance, which leads to the maintenance and exacerbation of pathological fear is closely linked to Pavlovian and operant conditioning processes. Changes in conditionability might represent a key feature of all anxiety disorders but the exact nature of these alterations might vary across different disorders. To date, no information is available on specific changes in conditionability for disorder-irrelevant stimuli in specific phobia (SP). The first aim of this study was to investigate changes in fear acquisition and extinction in spider-fearful individuals as compared to non-fearful participants by using the de novo fear conditioning paradigm. Secondly, we aimed to determine whether differences in the magnitude of context-dependent fear retrieval exist between spider-fearful and non-fearful individuals. Our findings point to an enhanced fear discrimination in spider-fearful individuals as compared to non-fearful individuals at both the physiological and subjective level. The enhanced fear discrimination in spider-fearful individuals was neither mediated by increased state anxiety, depression, nor stress tension. Spider-fearful individuals displayed no changes in extinction learning and/or fear retrieval. Surprisingly, we found no evidence for context-dependent modulation of fear retrieval in either group. Here, we provide first evidence that spider-fearful individuals show an enhanced discriminative fear learning of phobia-irrelevant (de novo) stimuli. Our findings provide novel insights into the role of fear acquisition and expression for the development and maintenance of maladaptive responses in the course of SP.
- Spectral and spatial selectivity of luminance vision in reef fish. [Journal Article]
- Front Neural Circuits 2014.:118.
Luminance vision has high spatial resolution and is used for form vision and texture discrimination. In humans, birds and bees luminance channel is spectrally selective-it depends on the signals of the long-wavelength sensitive photoreceptors (bees) or on the sum of long- and middle-wavelength sensitive cones (humans), but not on the signal of the short-wavelength sensitive (blue) photoreceptors. The reasons of such selectivity are not fully understood. The aim of this study is to reveal the inputs of cone signals to high resolution luminance vision in reef fish. Sixteen freshly caught damselfish, Pomacentrus amboinensis, were trained to discriminate stimuli differing either in their color or in their fine patterns (stripes vs. cheques). Three colors ("bright green", "dark green" and "blue") were used to create two sets of color and two sets of pattern stimuli. The "bright green" and "dark green" were similar in their chromatic properties for fish, but differed in their lightness; the "dark green" differed from "blue" in the signal for the blue cone, but yielded similar signals in the long-wavelength and middle-wavelength cones. Fish easily learned to discriminate "bright green" from "dark green" and "dark green" from "blue" stimuli. Fish also could discriminate the fine patterns created from "dark green" and "bright green". However, fish failed to discriminate fine patterns created from "blue" and "dark green" colors, i.e., the colors that provided contrast for the blue-sensitive photoreceptor, but not for the long-wavelength sensitive one. High resolution luminance vision in damselfish, Pomacentrus amboinensis, does not have input from the blue-sensitive cone, which may indicate that the spectral selectivity of luminance channel is a general feature of visual processing in both aquatic and terrestrial animals.
- Therapeutic Potential of 5-HT6 Antagonist SB399885 in Traumatic Stress Disorder. [JOURNAL ARTICLE]
- Drug Res (Stuttg) 2014 Oct 13.
Background: Post-traumatic stress disorder is an anxiety disorder for which current therapies are not effective. The 5-Hydroxytryptamine6 receptor antagonist SB399885 has been reported to have an anxiolytic effect. Hence, the current investigation was undertaken to evaluate its efficacy in post-traumatic stress disorder. Methods: Rats were placed in the operant box and given 3 foot shocks at intervals of 1 min. The following day the duration of freezing was recorded. For the enhanced sustained prolonged stress (ESPS), the rats were subjected to various stressors such as restraint stress (2 h), forced swim (20 min), and anesthesia, followed by a foot shock for 4 s. The rats were then subjected to the elevated plus maze. Results: Treatment with SB399885 (1 and 3 mg/kg, i. p.) was found to significantly decrease the freezing time in the contextual fear conditioning model. Rats subjected to ESPS spent greater time in the open arm of the elevated plus maze when administered SB399885 at the above mentioned doses. The treatment had no effect on locomotor activity. SB399885 decreased the 5-hydroxytryptamine levels in the amygdala at doses that were effective in the above animal models. Conclusion: 5-Hydroxytryptamine6 antagonists may hold potential in the treatment of post-traumatic stress.
- Corrigendum: Validation and extension of the reward-mountain model. [PUBLISHED ERRATUM]
- Front Behav Neurosci 2014.:310.
[This corrects the article on p. 125 in vol. 7, PMID: 24098275.].
- Self-recognition in pigeons revisited. [JOURNAL ARTICLE]
- J Exp Anal Behav 2014 Oct 13.
Recognition of a self-image in a mirror is investigated using the mark test during which a mark is placed onto a point on the body that is not directly visible, and the presence or absence of self-directed behaviors is evaluated for the mirror-observing subjects. Great apes, dolphins, possibly elephants, and magpies have all passed the mark test, that is, displayed self-directed behaviors, whereas monkeys, crows, and other animals have failed the test even though they were able to use a mirror to find a not-directly-visible object. Self-directed behavior and mirror use are prerequisites of a successful mark test, and the absence of these behaviors may lead to false negative results. Epstein, Lanza, and Skinner (1981) reported self-directed behavior of pigeons in front of a mirror after explicit training of self-directed pecking and of pecking an object with the aid of a mirror, but certain other researchers could not confirm the results. The aim of the present study was to conduct the mark test with two pigeons that had received extensive training of the prerequisite behaviors. Crucial points of the training were identical topography (pecking) and the same reinforcement (food) in the prerequisite behaviors as well as sufficient training of these behaviors. After training for the prerequisite behaviors, both pigeons spontaneously integrated the learned self-directed and mirror-use behavior and displayed self-directed behavior in a mark test. This indicates that pigeons display mirror self-recognition after training of suitable ontogenetic contingency.
- New epistemological foundations for cultural psychology: from an atomistic to a self-organizing view of living systems. [Journal Article]
- Ann Ist Super Sanita 2014; 50(3):268-77.
An epistemological foundation for cultural psychology is essential to neuro- and behavioural sciences for the challenge psychological sciences must currently face: searching for an explanation of how a brain can become a mind and how individuals assign a sense to the world and their life. Biological systems are very likely determined by physical and chemical laws of spontaneous self-organization and endogenous constraints but, even if the major result of the Darwinian revolution is "the discovery that living species are their story", the modern synthesis of the evolution theory adopted only continuist and gradualist hypotheses. This nourished the analogy between the theory of natural selection and the theory of operant conditioning, thereby supporting empiricist associationism and the methodological positivism of behavioural and "classical" cognitive psychologists. Current scientific contributions provide evidence to the need for psychotherapy and psychopathology of a new epistemological approach in order to connect research stemming from animal models, up to the most abstract levels of personal meaning. The complex system oriented approach, here described, called "post-rationalism", shaped by a change initiated by evolutionary epistemology. The regulation of emotions initially develops within interpersonal relationships and evolves during both phylogeny and ontogeny, according to complex self-organization processes, leading to the acquisition of Self-organizing abilities and the construction of personal meaning. Endorsing the epistemological similarities of neo-Darwinism and behaviourism, and differentiating from this, the above mentioned approach, emphasises the fact that clinical and psycho-therapeutical practice must be founded on the laws of biological organisation: the ongoing activity of neurobiological systems, including the more abstract domains of thought and language.
- Behavioral models of tinnitus and hyperacusis in animals. [Journal Article, Review]
- Front Neurol 2014.:179.
The phantom perception of tinnitus and reduced sound-level tolerance associated with hyperacusis have a high comorbidity and can be debilitating conditions for which there are no widely accepted treatments. One factor limiting the development of treatments for tinnitus and hyperacusis is the lack of reliable animal behavioral models of these disorders. Therefore, the purpose of this review is to highlight the current animal models of tinnitus and hyperacusis, and to detail the advantages and disadvantages of each paradigm. To date, this is the first review to include models of both tinnitus and hyperacusis.
- Reward components of feeding behavior are preserved during mouse aging. [Journal Article]
- Front Aging Neurosci 2014.:242.
Eating behavior depends on associations between the sensory and energetic properties of foods. Healthful balance of these factors is a challenge for industrialized societies that have an abundance of food, food choices and food-related cues. Here, we were interested in whether appetitive conditioning changes as a function of age. Operant and pavlovian conditioning experiments (rewarding stimulus was a palatable food) in male mice (aged 3, 6, and 15 months) showed that implicit (non-declarative) memory remains intact during aging. Two other essential components of eating behavior, motivation and hedonic preference for rewarding foods, were also found not to be altered in aging mice. Specifically, hedonic responding by satiated mice to isocaloric foods of differing sensory properties (sucrose, milk) was similar in all age groups; importantly, however, this paradigm disclosed that older animals adjust their energy intake according to energetic need. Based on the assumption that the mechanisms that control feeding are conserved across species, it would appear that overeating and obesity in humans reflects a mismatch between ancient physiological mechanisms and today's cue-laden environment. The implication of the present results showing that aging does not impair the ability to learn stimulus-food associations is that the risk of overeating in response to food cues is maintained through to old age.
- Repeated episodes of chronic intermittent ethanol promote insensitivity to devaluation of the reinforcing effect of ethanol. [JOURNAL ARTICLE]
- Alcohol 2014 Sep 6.
Studies in animal models have shown that repeated episodes of alcohol dependence and withdrawal promote escalation of drinking that is presumably associated with alterations in the addiction neurocircuitry. Using a lithium chloride-ethanol pairing procedure to devalue the reinforcing properties of ethanol, the present study determined whether multiple cycles of chronic intermittent ethanol (CIE) exposure by vapor inhalation also alters the sensitivity of drinking behavior to the devaluation of ethanol's reinforcing effects. The effect of devaluation on operant ethanol self-administration and extinction was examined in mice prior to initiation of CIE (short drinking history) and after repeated cycles of CIE or air control exposure (long drinking history). Devaluation significantly attenuated the recovery of baseline ethanol self-administration when tested either prior to CIE or in the air-exposed controls that had experienced repeated bouts of drinking but no CIE. In contrast, in mice that had undergone repeated cycles of CIE exposure that promoted escalation of ethanol drinking, self-administration was completely resistant to the effect of devaluation. Devaluation had no effect on the time course of extinction training in either pre-CIE or post-CIE mice. Taken together, these results are consistent with the suggestion that repeated cycles of ethanol dependence and withdrawal produce escalation of ethanol self-administration that is associated with a change in sensitivity to devaluation of the reinforcing properties of ethanol.