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Article ; Online: Patterns of motor activity in spontaneously hypertensive rats compared to Wistar Kyoto rats.

Fasmer, Ole Bernt / Johansen, Espen Borgå

Behavioral and brain functions : BBF

2016 Volume 12, Issue 1, Page(s) 32

Abstract: Background: Increased motor activity is a defining characteristic of patients with ADHD, and spontaneously hypertensive rats have been suggested to be an animal model of this disorder. In the present study, we wanted to use linear and non-linear methods ...

Abstract	Background: Increased motor activity is a defining characteristic of patients with ADHD, and spontaneously hypertensive rats have been suggested to be an animal model of this disorder. In the present study, we wanted to use linear and non-linear methods to explore differences in motor activity patterns in SHR/NCrl rats compared to Wistar Kyoto (WKY/NHsd) rats. Methods: A total number of 42 rats (23 SHR/NCrl and 19 WKY/NHsd, male and female) were tested. At PND 51, the animals' movements were video-recorded during an operant test procedure that lasted 90 min. Total activity level and velocity (mean and maximum), standard deviation (SD) and root mean square successive differences (RMSSD) were calculated. In addition, we used Fourier analysis, autocorrelations and two measures of complexity to characterize the time series; sample entropy and symbolic dynamics. Results: The SHR/NCrl rats showed increased total activity levels in addition to increased mean and maximum velocity of movements. The variability measures, SD and RMSSD, were markedly lower in the SHR/NCrl compared to the WKY/NHsd rats. At the same time, the SHR/NCrl rats displayed a higher complexity of the time series, particularly with regard to the total activity level as evidenced by analyses of sample entropy and symbolic dynamics. Autocorrelation analyses also showed differences between the two strains. In the Fourier analysis, the SHR/NCrl rats had an increased variance in the high frequency part of the spectrum, corresponding to the time period of 9-17 s. Conclusion: The findings show that in addition to increased total activity and velocity of movement, the organization of behavior is different in SHR/NCrl relative to WKY/NHsd controls. Compared to controls, behavioral variability is reduced in SHR/NCrl at an aggregate level, and, concomitantly, more complex and unpredictable from moment-to-moment. These finding emphasize the importance of the measures and methods used when characterizing behavioral variability. If valid for ADHD, the results indicate that decreased behavioral variability can co-exist with increased behavioral complexity, thus representing a challenge to current theories of variability in ADHD.
MeSH term(s)	Animals ; Attention Deficit Disorder with Hyperactivity/genetics ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Female ; Hypertension/genetics ; Hypertension/physiopathology ; Male ; Motor Activity/physiology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Species Specificity
Language	English
Publishing date	2016-12-01
Publishing country	England
Document type	Comparative Study ; Journal Article
ISSN	1744-9081
ISSN (online)	1744-9081
DOI	10.1186/s12993-016-0117-9
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: The irrelevancy of the inter-trial interval in delay-discounting experiments on an animal model of ADHD.

Sjoberg, Espen A / Ramos, Sergio / López-Tolsa, Gabriela E / Johansen, Espen Borgå / Pellón, Ricardo

Behavioural brain research

2021 Volume 408, Page(s) 113236

Abstract: Delay discounting involves choosing between a small, immediate reward, and a larger but delayed one. As the delay between choice and large reward gets longer, people with ADHD tend to become impulsive faster than controls, indicated by a switch in ... ...

Abstract	Delay discounting involves choosing between a small, immediate reward, and a larger but delayed one. As the delay between choice and large reward gets longer, people with ADHD tend to become impulsive faster than controls, indicated by a switch in preference from the large to the smaller reward. Choosing the smaller reward when the larger is considered reward maximizing is labeled impulsive behaviour. It is well documented that increased delays between choice and reward affects choice preference in both humans and other animals. Other variables such as the inter-trial interval or trial length are observed to have an effect on human discounting, but their effect on discounting in other animals is largely assumed rather than tested. In the current experiment, we tested this assumption. One group of rats was exposed to increasing delays between choosing the large reward and receiving it, while another group experienced longer inter-trial intervals that were equal in length to the delays in the other group. This ensured that trial length was controlled for in delay discounting, but that the delay function and inter-trial intervals could be manipulated and measured separately. Results showed that while the delay between choice and reward caused impulsive behaviour in rats, the length of the inter-trial interval (and by extension trial length) had no impact on choice behaviour. A follow-up experiment found this to be the case even if the length of the inter-trial interval was signaled with audio cues. These results suggest that rats, and possibly animals in general, are insensitive to time between trials, and therefore cannot easily represent human counterparts on the task.
MeSH term(s)	Animals ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Behavior, Animal/physiology ; Delay Discounting/physiology ; Disease Models, Animal ; Impulsive Behavior/physiology ; Male ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reward ; Time Factors ; Rats
Language	English
Publishing date	2021-03-13
Publishing country	Netherlands
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	449927-x
ISSN	1872-7549 ; 0166-4328
ISSN (online)	1872-7549
ISSN	0166-4328
DOI	10.1016/j.bbr.2021.113236
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Article: Rat models of ADHD.

Sagvolden, Terje / Johansen, Espen Borgå

Current topics in behavioral neurosciences

2012 Volume 9, Page(s) 301–315

Abstract: Showing that an animal is hyperactive is not sufficient for it to be accepted as a model of ADHD. Based on behavioral, genetic, and neurobiological data, the spontaneously hypertensive rat (SHR) obtained from Charles River, Germany, (SHR/NCrl) is at ... ...

Abstract	Showing that an animal is hyperactive is not sufficient for it to be accepted as a model of ADHD. Based on behavioral, genetic, and neurobiological data, the spontaneously hypertensive rat (SHR) obtained from Charles River, Germany, (SHR/NCrl) is at present the best-validated animal model of ADHD. One Wistar Kyoto substrain (WKY/NHsd), obtained from Harlan, UK, is its most appropriate control. Another WKY substrain (WKY/NCrl) obtained from Charles River, Germany, is inattentive, has distinctly different genetics and neurobiology, and provides a promising model for the predominantly inattentive subtype of ADHD (ADHD-I) if one wants to investigate categorical ADHD subtypes. In this case, also, the WKY/NHsd substrain should be used as control. Although other rat strains may behave like WKY/NHsd rats, neurobiological results indicate significant differences when compared to the WKY/NHsd substrain, making them less suitable as controls for the SHR/NCrl. Thus, there are no obvious behavioral differences among the various SHRs, but there are behavioral and neurobiological differences among the WKY strains. The use of WKY/NCrl, outbred Wistar, Sprague Dawley, or other rat strains as controls for SHR/NCrl may produce spurious neurobiological effects and erroneous conclusions. Finally, model data yield support to independent hyperactivity and inattention dimensions in ADHD behavior.
MeSH term(s)	Animals ; Attention Deficit Disorder with Hyperactivity/genetics ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Disease Models, Animal ; Rats ; Species Specificity
Language	English
Publishing date	2012
Publishing country	Germany
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1866-3370
ISSN	1866-3370
DOI	10.1007/7854_2011_126
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Article: Slower extinction of responses maintained by intra-cranial self-stimulation (ICSS) in an animal model of attention-deficit/hyperactivity disorder (ADHD).

Johansen, Espen Borgå / Sagvolden, Terje

Behavioural brain research

2005 Volume 162, Issue 1, Page(s) 22–31

Abstract: Children with attention-deficit/hyperactivity disorder (ADHD) show performance deficits and excessive motor activity during extinction and in situations where no reinforcer can be identified, suggesting an extinction deficit in ADHD possibly linked to ... ...

Abstract	Children with attention-deficit/hyperactivity disorder (ADHD) show performance deficits and excessive motor activity during extinction and in situations where no reinforcer can be identified, suggesting an extinction deficit in ADHD possibly linked to dopamine dysfunction. The present study examined extinction of responding previously maintained by intra-cranial self-stimulation (ICSS) in spontaneously hypertensive rats (SHR), an animal model of ADHD using three different extinction procedures. Delivery of electrical pulses were terminated altogether or presented independently of responding using two different current intensities. The results showed that more responses were retained in the SHR, especially during the initial transition from ICSS-maintained responding to response-independent delivery of electrical pulses with current reduced relative to that given during reinforcement. Slower extinction of previously reinforced behavior is suggested as an alternative explanation for the frequently observed increased behavioral output that has previously been interpreted as "disinhibition" of behavior in ADHD.
MeSH term(s)	Analysis of Variance ; Animals ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Behavior, Animal ; Conditioning, Operant/physiology ; Disease Models, Animal ; Dose-Response Relationship, Radiation ; Electric Stimulation/methods ; Extinction, Psychological/physiology ; Male ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reaction Time/physiology ; Reinforcement (Psychology) ; Reinforcement Schedule ; Self Stimulation/physiology ; Species Specificity ; Time Factors ; Ventral Tegmental Area/physiopathology ; Ventral Tegmental Area/radiation effects
Language	English
Publishing date	2005-07-01
Publishing country	Netherlands
Document type	Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	449927-x
ISSN	1872-7549 ; 0166-4328
ISSN (online)	1872-7549
ISSN	0166-4328
DOI	10.1016/j.bbr.2005.02.035
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Article: Behavioral effects of intra-cranial self-stimulation in an animal model of attention-deficit/hyperactivity disorder (ADHD).

Johansen, Espen Borgå / Sagvolden, Terje

Behavioural brain research

2005 Volume 162, Issue 1, Page(s) 32–46

Abstract: Attention deficit/hyperactivity disorder (ADHD), characterized by inappropriate levels of activity, attention, and impulsivity, has been suggested to be caused by changes in reinforcement and extinction processes possibly linked to dysfunctioning ... ...

Abstract	Attention deficit/hyperactivity disorder (ADHD), characterized by inappropriate levels of activity, attention, and impulsivity, has been suggested to be caused by changes in reinforcement and extinction processes possibly linked to dysfunctioning dopamine systems. The present study investigated reinforcement processes in spontaneously hypertensive rats (SHR), an animal model of ADHD. Using intra-cranial self-stimulation (ICSS), behavioral effects of varying current intensity, reinforcer density, and reinforcer delay were tested. Current was varied in order to find the weakest current producing the maximal response rate (optimal current) in the SHR and the controls during high (120 reinforcers/min) and low reinforcer densities (1 reinforcer/min). The results showed that optimal current was significantly lower in the SHR than in the controls during high reinforcer density while maximal response rates were not significantly different. During low reinforcer density, optimal current was not significantly different in the two strains, but maximal response rate was significantly higher in the SHR than in the controls. The SHR produced more responses during the testing of reinforcer density, but changes in reinforcer density affected response rates similarly in the two strains. The decrease in response rate as a function of reinforcer delay was more pronounced in the SHR than in the controls. Overall, more responses with short inter-response times (IRT) were found in the SHR compared to the controls during intermittent reinforcement. The results are consistent with a steepened delay-of-reinforcement gradient in SHR.
MeSH term(s)	Analysis of Variance ; Animals ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Behavior, Animal/physiology ; Brain/radiation effects ; Conditioning, Operant/physiology ; Disease Models, Animal ; Dose-Response Relationship, Radiation ; Electrodes ; Extinction, Psychological ; Inhibition (Psychology) ; Psychomotor Performance/physiology ; Random Allocation ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reaction Time ; Reinforcement (Psychology) ; Reinforcement Schedule ; Self Stimulation/physiology ; Species Specificity ; Time Factors
Language	English
Publishing date	2005-07-01
Publishing country	Netherlands
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	449927-x
ISSN	1872-7549 ; 0166-4328
ISSN (online)	1872-7549
ISSN	0166-4328
DOI	10.1016/j.bbr.2005.02.033
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Article: Response disinhibition may be explained as an extinction deficit in an animal model of attention-deficit/hyperactivity disorder (ADHD).

Johansen, Espen Borgå / Sagvolden, Terje

Behavioural brain research

2004 Volume 149, Issue 2, Page(s) 183–196

Abstract: Attention-deficit/hyperactivity disorder (ADHD) is a disorder affecting between 2 and 12% of grade-school children disturbing social, academic, and occupational functioning. Problems related to social adjustment and functioning and/or psychiatric ... ...

Abstract	Attention-deficit/hyperactivity disorder (ADHD) is a disorder affecting between 2 and 12% of grade-school children disturbing social, academic, and occupational functioning. Problems related to social adjustment and functioning and/or psychiatric problems will exist in 50-70% of adolescents and young adults diagnosed with ADHD as children. It has been suggested that altered reinforcement and extinction processes may cause the symptoms of ADHD. The present study investigated extinction processes in spontaneously hypertensive rats (SHR), possibly the best-validated animal model of ADHD. Extinction was tested after either a variable interval (VI) or a fixed interval (FI) schedule of reinforcement with and without the presence of a conditioned reinforcer (light in the water cubicle). The results indicate a slower extinction process in the SHR compared to the normal controls, especially during the initial transition from scheduled reinforcement to extinction. Also, more responses were retained in the SHR during the later part of extinction. The extinction deficit in the SHR may be linked to reinforcer unpredictability and the presence of conditioned reinforcers, and may explain response disinhibition seen in children with ADHD.
MeSH term(s)	Analysis of Variance ; Animals ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Behavior, Animal ; Conditioning, Operant/physiology ; Disease Models, Animal ; Extinction, Psychological/physiology ; Inhibition (Psychology) ; Male ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reinforcement (Psychology) ; Reinforcement Schedule
Language	English
Publishing date	2004-04-15
Publishing country	Netherlands
Document type	Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	449927-x
ISSN	1872-7549 ; 0166-4328
ISSN (online)	1872-7549
ISSN	0166-4328
DOI	10.1016/s0166-4328(03)00229-8
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Article ; Online: Animal models of attention-deficit hyperactivity disorder.

Russell, Vivienne A / Sagvolden, Terje / Johansen, Espen Borgå

Behavioral and brain functions : BBF

2005 Volume 1, Page(s) 9

Abstract: Although animals cannot be used to study complex human behaviour such as language, they do have similar basic functions. In fact, human disorders that have animal models are better understood than disorders that do not. ADHD is a heterogeneous disorder. ... ...

Abstract	Although animals cannot be used to study complex human behaviour such as language, they do have similar basic functions. In fact, human disorders that have animal models are better understood than disorders that do not. ADHD is a heterogeneous disorder. The relatively simple nervous systems of rodent models have enabled identification of neurobiological changes that underlie certain aspects of ADHD behaviour. Several animal models of ADHD suggest that the dopaminergic system is functionally impaired. Some animal models have decreased extracellular dopamine concentrations and upregulated postsynaptic dopamine D1 receptors (DRD1) while others have increased extracellular dopamine concentrations. In the latter case, dopamine pathways are suggested to be hyperactive. However, stimulus-evoked release of dopamine is often decreased in these models, which is consistent with impaired dopamine transmission. It is possible that the behavioural characteristics of ADHD result from impaired dopamine modulation of neurotransmission in cortico-striato-thalamo-cortical circuits. There is considerable evidence to suggest that the noradrenergic system is poorly controlled by hypofunctional alpha2-autoreceptors in some models, giving rise to inappropriately increased release of norepinephrine. Aspects of ADHD behaviour may result from an imbalance between increased noradrenergic and decreased dopaminergic regulation of neural circuits that involve the prefrontal cortex. Animal models of ADHD also suggest that neural circuits may be altered in the brains of children with ADHD. It is therefore of particular importance to study animal models of the disorder and not normal animals. Evidence obtained from animal models suggests that psychostimulants may not be acting on the dopamine transporter to produce the expected increase in extracellular dopamine concentration in ADHD. There is evidence to suggest that psychostimulants may decrease motor activity by increasing serotonin levels. In addition to providing unique insights into the neurobiology of ADHD, animal models are also being used to test new drugs that can be used to alleviate the symptoms of ADHD.
Language	English
Publishing date	2005-07-15
Publishing country	England
Document type	Journal Article
ISSN	1744-9081
ISSN (online)	1744-9081
DOI	10.1186/1744-9081-1-9
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Article: Effects of delayed reinforcers on the behavior of an animal model of attention-deficit/hyperactivity disorder (ADHD).

Johansen, Espen Borgå / Sagvolden, Terje / Kvande, Grethe

Behavioural brain research

2005 Volume 162, Issue 1, Page(s) 47–61

Abstract: Attention-deficit/hyperactivity disorder (ADHD), affecting 3-5% of grade-school children, is a behavioral disorder characterized by developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. It has been suggested that the ... ...

Abstract	Attention-deficit/hyperactivity disorder (ADHD), affecting 3-5% of grade-school children, is a behavioral disorder characterized by developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. It has been suggested that the symptoms are caused by altered reinforcement and extinction processes, behaviorally described as an abnormally short and steep delay-of-reinforcement gradient in ADHD. The present study tested predictions from the suggested shortened and steepened delay gradient in ADHD in an animal model, the spontaneously hypertensive rats (SHRs). It was predicted that SHR responding during baseline would mainly consist of responses with short inter-response times, and that responding would be more rapidly reduced in the SHR than in the controls by the introduction of a time interval between the response and reinforcer delivery. Effects of a resetting delay of reinforcement procedure with water as the reinforcer were tested on two baseline reinforcement schedules: variable interval 30 s (VI 30 s) and conjoint variable interval 60 s differential reinforcement of high rate 1s (VI 60 s DRH 1 s). The results showed a higher rate of responses in the SHR than in the controls during baseline, mainly consisting of responses with short inter-response times. The statistical analyses showed that response rates decreased more rapidly as a function of reinforcer delay in the SHR than in the controls. The analyses of the estimates of the reinforcer decay parameter showed no strain differences during the VI 30 s schedule but showed a significant strain difference at the end, but not at the start, of the sessions during the VI 60 s DRH 1 s schedule. In general, the results support predictions from the suggested steepened delay gradient in SHR. However, the predictions were only partly confirmed by the analyses of the decay parameter.
MeSH term(s)	Analysis of Variance ; Animals ; Attention Deficit Disorder with Hyperactivity/physiopathology ; Behavior, Animal/physiology ; Brain/radiation effects ; Conditioning, Operant/physiology ; Disease Models, Animal ; Dose-Response Relationship, Radiation ; Electrodes ; Extinction, Psychological ; Inhibition (Psychology) ; Male ; Predictive Value of Tests ; Psychomotor Performance/physiology ; Random Allocation ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reaction Time ; Reinforcement (Psychology) ; Reinforcement Schedule ; Self Stimulation/physiology ; Species Specificity ; Time Factors
Language	English
Publishing date	2005-07-01
Publishing country	Netherlands
Document type	Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	449927-x
ISSN	1872-7549 ; 0166-4328
ISSN (online)	1872-7549
ISSN	0166-4328
DOI	10.1016/j.bbr.2005.02.034
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Article ; Online: Behavioral changes following PCB 153 exposure in the spontaneously hypertensive rat - an animal model of Attention-Deficit/Hyperactivity Disorder.

Johansen, Espen Borgå / Fonnum, Frode / Lausund, Per L / Walaas, S Ivar / Bærland, Nora Elise / Wøien, Grete / Sagvolden, Terje

Behavioral and brain functions : BBF

2014 Volume 10, Page(s) 1

Abstract: Background: Attention-Deficit/Hyperactivity Disorder (ADHD) is a behavioral disorder affecting 3-5% of children. Although ADHD is highly heritable, environmental factors like exposure during early development to various toxic substances like ... ...

Abstract	Background: Attention-Deficit/Hyperactivity Disorder (ADHD) is a behavioral disorder affecting 3-5% of children. Although ADHD is highly heritable, environmental factors like exposure during early development to various toxic substances like polychlorinated biphenyls (PCBs) may contribute to the prevalence. PCBs are a group of chemical industrial compounds with adverse effects on neurobiological and cognitive functioning, and may produce behavioral impairments that share significant similarities with ADHD. The present study examined the relation between exposure to PCB 153 and changes in ADHD-like behavior in an animal model of ADHD, the spontaneously hypertensive rats (SHR/NCrl), and in Wistar Kyoto (WKY/NHsd) controls. Methods: SHR/NCrl and WKY/NHsd, males and females, were orally given PCB 153 dissolved in corn oil at around postnatal day (PND) 8, 14, and 20 at a dosage of 1, 3 or 6 mg/kg bodyweight at each exposure. The control groups were orally administered corn oil only. The animals were behaviorally tested for exposure effects from PND 37 to 64 using an operant procedure. Results: Exposure to PCB 153 was associated with pronounced and long-lasting behavioral changes in SHR/NCrl. Exposure effects in the SHR/NCrl depended on dose, where 1 mg/kg tended to reduce ADHD-like behaviors and produce opposite behavioral effects compared to 3 mg/kg and 6 mg/kg, especially in the females. In the WKY/NHsd controls and for the three doses tested, PCB 153 exposure produced a few specific behavioral changes only in males. The data suggest that PCB 153 exposure interacts with strain and sex, and also indicate a non-linear dose-response relation for the behaviors observed. Conclusions: Exposure to PCB 153 seems to interact with several variables including strain, sex, dose, and time of testing. To the extent that the present findings can be generalized to humans, exposure effects of PCB 153 on ADHD behavior depends on amount of exposure, where high doses may aggravate ADHD symptoms in genetically vulnerable individuals. In normal controls, exposure may not constitute an environmental risk factor for developing the full range of ADHD symptoms, but can produce specific behavioral changes.
MeSH term(s)	Animals ; Attention Deficit Disorder with Hyperactivity/psychology ; Behavior, Animal/drug effects ; Conditioning, Operant/drug effects ; Disease Models, Animal ; Female ; Habituation, Psychophysiologic/drug effects ; Humans ; Male ; Polychlorinated Biphenyls/pharmacology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Species Specificity
Chemical Substances	Polychlorinated Biphenyls (DFC2HB4I0K) ; 2,4,5,2',4',5'-hexachlorobiphenyl (ZRU0C9E32O)
Language	English
Publishing date	2014-01-09
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1744-9081
ISSN (online)	1744-9081
DOI	10.1186/1744-9081-10-1
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Progressive ratio schedules of reinforcement.

Killeen, Peter R / Posadas-Sanchez, Diana / Johansen, Espen Borgå / Thrailkill, Eric A

Journal of experimental psychology. Animal behavior processes

2009 Volume 35, Issue 1, Page(s) 35–50

Abstract: Pigeons' pecks produced grain under progressive ratio (PR) schedules, whose response requirements increased systematically within sessions. Experiment 1 compared arithmetic (AP) and geometric (GP) progressions. Response rates increased as a function of ... ...

Abstract	Pigeons' pecks produced grain under progressive ratio (PR) schedules, whose response requirements increased systematically within sessions. Experiment 1 compared arithmetic (AP) and geometric (GP) progressions. Response rates increased as a function of the component ratio requirement, then decreased linearly (AP) or asymptotically (GP). Experiment 2 found the linear decrease in AP rates to be relatively independent of step size. Experiment 3 showed pausing to be controlled by the prior component length, which predicted the differences between PR and regressive ratio schedules found in Experiment 4. When the longest component ratios were signaled by different key colors, rates at moderate ratios increased, demonstrating control by forthcoming context. Models for response rate and pause duration based on Bizo and Killeen (1997) described performance on AP schedules; GP schedules required an additional parameter representing the contextual reinforcement.
MeSH term(s)	Animals ; Behavior, Animal ; Columbidae ; Male ; Models, Psychological ; Reaction Time ; Reinforcement Schedule
Language	English
Publishing date	2009-01-22
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	2067423-5
ISSN	1939-2184 ; 0097-7403
ISSN (online)	1939-2184
ISSN	0097-7403
DOI	10.1037/a0012497
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