Single‐case experimental designs for behavioral neuroscience

Abstract

Single-case experimental designs (SCEDs) are commonly used in behavior analytic research but rarely used in behavioral neuroscience research. The recent development of technologies that allow control of the timing of neurobiological events such as gene expression and neuronal firing enable the fruitful application of SCEDs for the study of brain-behavior relations. There are at least 3 benefits expected from applying SCEDs to study how neurobiological events affect behavior. First, SCEDs entail direct within-and across-subject assessments of reliability, likely increasing the probability of replication across studies and encouraging a search for the causes of replication failure when they occur. Second, SCEDs focus on behavior in individual organisms producing a body of knowledge that applies to individuals rather than population parameters. Finally, SCEDs require fewer animals, decreasing costs and effort and addressing the ethical obligation to reduce the number of animals used for research. Examples are provided using hypothetical data generated based on published research. Collaborations between behavior analysts and behavioral neuroscientists will bring the world within the skin under direct experimental control and broaden our understanding of the determinants of behavior.

A method for studying reinforcement factors controlling impulsive choice for use in behavioral neuroscience

“…Unfortunately, the steady‐state methods that have been so useful in behavior analysis can be quite time‐consuming, particularly when experiments involve parametric investigations, and thus, in many cases, they are not very practical for investigating effects of neurobiological manipulations on behavioral processes. We believe the type of procedure described here overcomes this practical limitation, while retaining some of the key advantages of single‐subject experimental designs (see Soto, 2020 for an excellent case for using single‐subject designs in behavioral neuroscience). The data presented here illustrate that behavior comes under good control of the dimensions of reinforcement and does so relatively rapidly.…”

Dynamic effects of dietary protein restriction on body weights, food consumption, and protein preference in C57BL/6J and Fgf21‐KO mice

“…Second, as described by many authors, group average results do not necessarily predict effects at the individual level (Branch, 2019; Branch & Pennypacker, 2013; Gallistel et al, 2004; Iversen, 2021; Sidman, 1960), whereas the current data allow direct estimation of the magnitude of effect that can be expected in individual mice and the reliability of those effects across mice. Third, these results indicate that individual animals can serve as their own controls for experiments on protein restriction, which can be extremely useful for labor‐, time‐, and resource‐intensive studies of the neurobiology underlying the effects of protein restriction (see Soto, 2020).…”

“…magnitude of effect that can be expected in individual mice and the reliability of those effects across mice. Third, these results indicate that individual animals can serve as their own controls for experiments on protein restriction, which can be extremely useful for labor-, time-, and resource-intensive studies of the neurobiology underlying the effects of protein restriction (see Soto, 2020).…”

“…Single-case experimental designs (SCEDs) are rarely used in behavioral neuroscience research despite their potential benefits (Soto, 2020). In their most basic forms, SCEDs rely on the comparisons from conditions across which an experimental variable is manipulated within the same participant or subject to assess the effects of the experimental variable on behavior or another dependent variable of interest.…”

“…A SCED approach to answer the same question could feasibly reduce the number of groups and therefore mice by half if the effects of dietary protein restriction could be investigated within each genotype. Further, as described above, investigations of the neurobiological substrates underlying the effects of protein restriction that rely on labor‐ and resource‐intensive technologies (e.g., fiber photometry, optogenetics, chemogenetics) similarly would benefit from using a SCED approach (see Soto, 2020), but such an approach requires that experimental manipulations produce reliable effects in individual animals.…”