Experience-dependent plasticity: differential changes in activation associated with repeated reinforcement.

Experience-dependent change in blood-oxygen-level-dependent (BOLD) signal is increasingly being employed in neuroimaging research to examine questions about function and plasticity. In this investigation, plasticity was examined during consecutive visual cue presentations that preceded correct button presses and subsequent reinforcer deliveries. Using functional neuroimaging and a modified repeated acquisition methodology, 10 adult subjects learned, through trial and error, a series of novel cue-response-reinforcer relations. Separate BOLD responses were obtained to consecutive cues and reinforcers. Repeated measures analysis of variance highlighted differential BOLD response changes. Consecutive visual cue presentations elicited rapid bilateral increases in activation in the anterior cingulate and medial frontal gyrus and moderate increases in medial temporal lobe structures and the striatum. Consecutive reinforcer presentations elicited rapid increases in activation in the left precuneus, lingual and fusiform gyri and moderate increases in medial temporal lobe structures and striatum. Within the medial temporal lobe, cues elicited a gradual increase then an abrupt decrease in activation and rewards elicited abrupt and then sustained activation. Consideration of experience-dependent BOLD response change and variability provides basic research a new perspective from which to examine regional plasticity and further explore dynamic experience-dependent shifts among cognitive processes. Furthermore, BOLD change and variability offer many clinical research areas novel supplemental indices of neuropathology.

Loading the problem loader: the effects of target training and shaping on trailer-loading behavior of horses.

The purpose of this study was to develop an effective method for trailer loading horses based on principles of positive reinforcement. Target training and shaping were used to teach trailer-loading behavior to 5 quarter horse mares in a natural setting. All 5 had been trailer loaded before through the use of aversive stimulation. Successive approximations to loading and inappropriate behaviors were the dependent variables. After training a horse to approach a target, the target was moved to various locations inside the trailer. Horses started training on the left side of a two-horse trailer. After a horse was loading on the left side, she was moved to the right side, then to loading half on the right and half on the left. A limited-hold procedure and the presence of a companion horse seemed to facilitate training for 1 horse. Inappropriate behaviors fell to zero immediately after target training, and all the horses successfully completed the shaping sequence. Finally, these effects were observed to generalize to novel conditions (a different trainer and a different trailer).

Behavioral cusps: a developmental and pragmatic concept for behavior analysis.

Most concepts of development explain certain behavior changes as products or markers of the invariable succession of emerging periods, stages, refinements, or achievements that define and order much of an individual's life. A different but comparable concept can be derived from the most basic mechanisms of behavior analysis, which are its environmental contingencies, and from its most basic strategy, which is to study behavior as its subject matter. From a behavior-analytic perspective, the most fundamental developmental questions are (a) whether these contingencies vary in any systematic way across the life span, and thus make behavior change in a correspondingly systematic way; (b) whether some of these contingencies and their changes have more far-reaching consequences than others, in terms of the importance to the organism and others, of the behavior classes they change. Certain behavior changes open the door to especially broad or especially important further behavior change, leading to the concept of the behavioral cusp. A behavioral cusp, then, is any behavior change that brings the organism's behavior into contact with new contingencies that have even more far-reaching consequences. Of all the environmental contingencies that change or maintain behavior, those that accomplish cusps are developmental. Behavior change remains the fundamental phenomenon of development for a behavior-analytic view; a cusp is a special instance of behavior change, a change crucial to what can come next.

The effect of object preferences on task performance and stereotypy in a child with autism.

The relationship between preferred objects associated with stereotypy, stereotypic behavior, and accuracy of responding during a counting task by a child with autism was analyzed. Object preference was determined by presenting the child with different sets of objects and asking him to choose one. His choices were then rank ordered into three groups: low, medium, and high preference objects. Counting performance within each of the three object groups was then analyzed in a multi-element design, alternating preference groups. Teaching with high-preference objects occasioned more stereotypic behavior and less accurate counting than teaching with medium- and low-preference objects. Thus, there exists the possibility that teaching may be less successful with certain teaching materials, especially if those materials evoke high rates of incompatible behaviors.