Bryant C. Silbaugh

Age-related changes in conditioned flavor preference in rats

Age-related changes have been documented in regions of the brain shown to process reward information. However, few studies have examined the effects of aging on associative memory for reward. The present study tested 7- and 24-month-old rats on a conditioned flavor preference task. Half of the rats in each age group received an unsweetened grape-flavored solution (CS-) on odd-numbered days and a sweetened cherry-flavored solution (CS+) on even-numbered days. The remaining rats in each age group received a sweetened grape-flavored solution (CS+) on odd-numbered days and an unsweetened cherry-flavored solution (CS-) on even-numbered days. During the acquisition phase of testing, the designated solution (CS+ or CS-) was presented to each rat for 15 min daily across six consecutive days. On the preference phase, each rat received unsweetened cherry and unsweetened grape-flavored solutions simultaneously for 15 min daily across four consecutive days. The 7-month-old rats showed a significant preference for the flavor that was previously sweetened during the acquisition phase (CS+) compared to the previously unsweetened solution (CS-) when the two unsweetened solutions were presented simultaneously during the preference phase of testing. In contrast, the 24-month-old rats did not show a preference and consumed roughly equal amounts of the previously sweetened (CS+) and unsweetened (CS-) solutions. Thus, the data suggest that the ability to form flavor-reward associations declines with increasing age, resulting in impaired conditioned flavor preference.

Chemosensory responsiveness to ethanol and its individual sensory components in alcohol-preferring, alcohol-nonpreferring and genetically heterogeneous rats

Alcohol activates orosensory circuits that project to motivationally relevant limbic forebrain areas that control appetite, feeding and drinking. To date, limited data exists regarding the contribution of chemosensory‐derived ethanol reinforcement to ethanol preference and consumption. Measures of taste reactivity to intra‐orally infused ethanol have not found differences in initial orofacial responses to alcohol between alcohol‐preferring (P) and alcohol‐non‐preferring (NP) genetically selected rat lines. Yet, in voluntary intake tests, P rats prefer highly concentrated ethanol upon initial exposure, suggesting an early sensory‐mediated attraction. Here, we directly compared self‐initiated chemosensory responding for alcohol and prototypic sweet, bitter and oral trigeminal stimuli among selectively bred P, NP and non‐selected Wistar (WI) outbred lines to determine whether differential sensory responsiveness to ethanol and its putative sensory components are phenotypically associated with genetically influenced alcohol preference. Rats were tested for immediate short‐term lick responses to alcohol (3–40%), sucrose (0.01–1 M), quinine (0.01–3 mM) and capsaicin (0.003–1 mM) in a brief‐access assay designed to index orosensory‐guided behavior. P rats exhibited elevated short‐term lick responses to both alcohol and sucrose relative to NP and WI lines across a broad range of concentrations of each stimulus and in the absence of blood alcohol levels that would produce significant post‐absorptive effects. There was no consistent relationship between genetically mediated alcohol preference and orosensory avoidance of quinine or capsaicin. These data indicate that enhanced initial chemosensory attraction to ethanol and sweet stimuli are phenotypes associated with genetic alcohol preference and are considered within the framework of downstream activation of oral appetitive reward circuits.

Translational evaluation of a lag schedule and variability in food consumed by a boy with autism and food selectivity

ABSTRACT Purpose: To evaluate the effects of a lag schedule of positive reinforcement on variability in food consumed by a boy with autism and food selectivity. Methods: Using single-subject experimental design methodology, an ABAB design was employed. During lag 0 (condition A), high-preferred toys were delivered contingent on consumption of any food. During lag 1 (condition B), high-preferred toys were delivered contingent on consumption of different foods within session. Results: Higher levels of variability in within-session consumption were observed during lag 1 conditions. Conclusions: The lag 1 schedule of reinforcement increased variability in food consumed. This finding adds to the literature by demonstrating a novel experimental arrangement that may be used in applied studies to evaluate the clinical utility of differentially reinforcing variability in the treatment of food selectivity associated with autism.

Failure to Replicate the Effects of the High-Probability Instructional Sequence on Feeding in Children With Autism and Food Selectivity

Behavioral intervention has positive effects on feeding problems of children with autism and food selectivity (FS), and researchers have evaluated a variety of specific behavioral interventions. Confidence in the effects of some specific interventions on feeding such as the high-probability instructional sequence (HPS) is limited by a lack of replication. Therefore, we assessed the generality of the HPS by replicating the intervention in children with autism and FS. Contrary to prior research, the HPS did not improve feeding responses for three consecutive children enrolled in the study. We discuss the results in relation to publishing failures to replicate without experimental control in applied behavior analysis research.

Effects of a lag schedule of reinforcement with progressive time delay on topographical mand variability in children with autism

ABSTRACT Objective: Evaluate the effects of a Lag 1 schedule of reinforcement and progressive time delay (TD) on topographical mand variability in children with autism. Methods: Using single-subject design methodology, a multiple baseline across behaviors with embedded reversal design was employed. During Lag 0, reinforcement was delivered contingent on any independent instances of manding. During Lag 1 + TD, prompts were faded and reinforcement was delivered contingent on independent or prompted variant mand topographies. Results: Higher levels of topographical mand variability were observed during Lag 1 + TD for both participants. Conclusions: A Lag 1 schedule of reinforcement with progressive TD increased variability across functionally equivalent vocal mand topographies for both participants. This finding extends prior literature by providing a novel model for studying reinforced mand variability in children, and by demonstrating how practitioners could use prompts and differential reinforcement to increase topographical mand variability in children with autism.

Lag Schedules and Functional Communication Training: Persistence of Mands and Relapse of Problem Behavior:

We evaluated the effects of lag schedules of reinforcement and functional communication training (FCT) on mand variability and problem behavior in two children with autism spectrum disorder. Specifically, we implemented FCT with increasing lag schedules and compared its effects on problem behavior with baseline conditions. The results showed that both participants exhibited low rates of problem behavior during treatment relative to baseline during and following schedule thinning (up to a Lag 5 schedule arrangement). Variable and total mands remained high during schedule thinning. With one participant, variable manding persisted when the value of the lag schedule was reduced to zero. The current results are discussed in terms of implications for training multiple mand topographies during FCT for the potential prevention and/or mitigation of clinical relapse during challenges to treatment.

Effects of a Lag Schedule with Progressive Time Delay on Sign Mand Variability in a Boy with Autism

For some children with autism, mand training can produce highly repetitive manding unless the environment is arranged in a manner that promotes mand variability. Prior research demonstrated that mand training using a lag schedule and progressive time delay increased variability in vocal manding in children with autism. Whether lag schedules have similar effects on sign mand topographies is unknown. The current study evaluated the effects of mand training with a Lag 1 schedule of reinforcement and progressive time delay (TD) on topographical variability and the development of a sign mand response class hierarchy in a boy with autism. The results suggest independent use of all sign mand topographies occurred, a mand response class hierarchy was developed, and topographically variant sign manding increased under the Lag 1 + TD schedule compared to a Lag 0 schedule of reinforcement. Implications for practitioners, limitations, and directions for future research are discussed.

Synthesis of Applied Behavior Analytic Interventions for Packing in Pediatric Feeding Disorders

Packing, which consists of holding food in the mouth for an extended time during meals, is a form of disordered feeding associated with pediatric feeding disorders. The behavior can disrupt the pace and completion of a meal and lead to increased risk of choking, inadequate food and liquid intake, and elevated caregiver stress associated with mealtimes. Applied behavior analysis research has developed and evaluated behavioral interventions to improve feeding by reducing packing. This systematic review extends prior research by synthesizing characteristics of the packing intervention literature, evaluating the certainty of the evidence provided by studies, identifying potential directions for future research, and discussing the results in the context of evidence-based practice.