The irrelevancy of the inter-trial interval in delay-discounting experiments on an animal model of ADHD

Sjoberg, Espen A.; Ramos, Sérgio; López-Tolsa, Gabriela E.; Johansen, Espen Borgå; Pellón, Ricardo

doi:10.1016/j.bbr.2021.113236

Cited by 7 publications

(10 citation statements)

References 57 publications

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“…One possibility is that both the SHRs and Lphn3 KO rats exhibit impulsive choice, but they present the impairment differently. As previously mentioned, DD deficits have been previously reported in SHRs (Fox et al, 2008;Sjoberg et al, 2021). These results and ours indicate that the SHRs have a substantial problem with delay of gratification.…”

Section: Figuresupporting

confidence: 90%

“…Rather, the delivery of the reinforcer needed to occur soon after lever selection, so they choose the smaller, but immediate reward. As mentioned by Sjoberg et al DD performance by SHRs strongly supports Dynamic Developmental Behavioral Theory, which argues the salience of a reinforcer decreases as it is separated in time from the response made to achieve it (Sagvolden et al, 2005a;Sjoberg et al, 2021).…”

Section: Figuresupporting

confidence: 57%

“…In Experiment II, we incorporated a 1-s ITI immediately after delivery of either the immediate (1 pellet) or delayed (3 pellet) reinforcer. Because previous research has already shown the length of the ITI does not appear to influence choice behavior in SHRs (Sjoberg et al, 2021), we only tested Lphn3 KO and WT rats in Experiment II. We predicted that the Lphn3 KO rats would choose the small, immediate reward more often that the larger, delayed reward relative to the WT rats, thereby demonstrating an increase Percent choice for the larger reward during acquisition (top) and maintenance responding (bottom) for the Lphn3 −/− (knockout) and Lphn3 +/+ (wildtype) rats with equal trial lengths.…”

Section: Experiments IImentioning

confidence: 99%

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Impulsive choice in two different rat models of ADHD—Spontaneously hypertensive and Lphn3 knockout rats

et al. 2023

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IntroductionImpulsivity is a symptom of attention-deficit/hyperactivity disorder (ADHD) and variants in the Lphn3 (Adgrl3) gene (OMIM 616417) have been linked to ADHD. This project utilized a delay-discounting (DD) task to examine the impact of Lphn3 deletion in rats on impulsive choice. “Positive control” measures were also collected in spontaneously hypertensive rats (SHRs), another animal model of ADHD.MethodsFor Experiment I, rats were given the option to press one lever for a delayed reward of 3 food pellets or the other lever for an immediate reward of 1 pellet. Impulsive choice was measured as the tendency to discount the larger, delayed reward. We hypothesized that impulsive choice would be greater in the SHR and Lphn3 knockout (KO) rats relative to their control strains - Wistar-Kyoto (WKY) and Lphn3 wildtype (WT) rats, respectively.ResultsThe results did not completely support the hypothesis, as only the SHRs (but not the Lphn3 KO rats) demonstrated a decrease in the percent choice for the larger reward. Because subsequent trials did not begin until the end of the delay period regardless of which lever was selected, rats were required to wait for the next trial to start even if they picked the immediate lever. Experiment II examined whether the rate of reinforcement influenced impulsive choice by using a DD task that incorporated a 1 s inter-trial interval (ITI) immediately after delivery of either the immediate (1 pellet) or delayed (3 pellet) reinforcer. The results of Experiment II found no difference in the percent choice for the larger reward between Lphn3 KO and WT rats, demonstrating reinforcement rate did not influence impulsive choice in Lphn3 KO rats.DiscussionOverall, there were impulsivity differences among the ADHD models, as SHRs exhibited deficits in impulsive choice, while the Lphn3 KO rats did not.

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Section: Figuresupporting

confidence: 90%

Section: Figuresupporting

confidence: 57%

Section: Experiments IImentioning

confidence: 99%

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Impulsive choice in two different rat models of ADHD—Spontaneously hypertensive and Lphn3 knockout rats

et al. 2023

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“…Humans, though, may be different than other animals. Blanchard and others (Blanchard et al, 2013) showed, for instance, that monkeys do not optimize overall rate of reinforcement in discounting tasks, because they do not take into account the post reward ITI after the short delay, unless it is cued; nor do rats, even when cued (Sjoberg et al, 2021; but see Smethells & Reilly, 2015). That they do is a key assumption of Equations 2 and 3.…”

Section: Rachlin's Basic Model For Probabilistic Outcomesmentioning

confidence: 99%

“…To fit his data Mazur had to develop Equation 2 differently: The time variable had to include cumulative trial time until an eventual reinforcer, even if interrupted by time when the other alternative was chosen; but did not include the ITI (if differentially signalled: Mazur, 1991). For pigeons, it is the trial time, not the ITI, that matters, as it largely did for Blanchard et al (2013) and Sjoberg et al (2021). For these subjects, Rachlin et al (1986;1991) dropped the wrong interval: They should have dropped t ITI , not t T .…”

Section: Rachlin's Basic Model For Probabilisticmentioning

confidence: 99%

Variations on a theme by Rachlin: Probability discounting

Killeen

2022

J Exper Analysis Behavior

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Rachlin and colleagues laid the groundwork for treating the discounting of probabilistic goods as a variant of the discounting of delayed goods. This approach was seminal for a large body of subsequent research. The present paper finds the original development problematic: In converting probability to delay, the authors incorrectly dropped trial duration. The subsumption of probability by delay is also empirically questionable, as those are different functions of variables such as magnitude of outcome and commodity versus money. A variant of Rachlin's theme treats human discounting studies as psychophysical matching experiments, in which one compound stimulus is adjusted to equal another. It is assumed that a function of amount (its utility) is multiplied by a function of probability (its weight).Conjoint measurement establishes the nature of these functions, yielding a logarithmic transform on amount, and a Prelec function on probability. This model provides a good and parsimonious account of probability discounting in diverse data sets. Variant representations of the data are explored. By inserting the probabilistically discounted utility into the additive utility theory of delay discounting, a general theory of probabilistic intertemporal choice is achieved.

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Timing and delay discounting in attention‐deficit/hyperactivity disorder: A translational approach

Fox,

Nicholson,

Singha

et al. 2023

Developmental Psychobiology

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Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that often presents with abnormal time perception and increased impulsive choice behavior. The spontaneously hypertensive rat (SHR) is the most widely used preclinical model of the ADHD-Combined and ADHD-Hyperactive/Impulsive subtypes of the disorder. However, when testing the spontaneously hypertensive rat from Charles River (SHR/NCrl) on timing and impulsive choice tasks, the appropriate control strain is not clear, and it is possible that one of the possible control strains, the Wistar Kyoto from Charles River (WKY/NCrl), is an appropriate model for ADHD-Predominately Inattentive. Our goals were to test the SHR/NCrl, WKY/NCrl, and Wistar (WI; the progenitor strain for the SHR/NCrl and WKY/NCrl) strains on time perception and impulsive choice tasks to assess the validity of SHR/NCrl and WKY/NCrl as models of ADHD, and the validity of the WI strain as a control. We also sought to assess impulsive choice behavior in humans diagnosed with the three subtypes of ADHD and compare them with our findings from the preclinical models. We found SHR/NCrl rats timed faster and were more impulsive than WKY/NCrl and WI rats, and human participants diagnosed with ADHD were more impulsive compared to controls, but there were no differences between the three ADHD subtypes.

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The irrelevancy of the inter-trial interval in delay-discounting experiments on an animal model of ADHD

Cited by 7 publications

References 57 publications

Impulsive choice in two different rat models of ADHD—Spontaneously hypertensive and Lphn3 knockout rats

Impulsive choice in two different rat models of ADHD—Spontaneously hypertensive and Lphn3 knockout rats

Variations on a theme by Rachlin: Probability discounting

Timing and delay discounting in attention‐deficit/hyperactivity disorder: A translational approach

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