Modeling behavioral recovery following lesion induction in the rat dentate gyrus

Unilateral entorhinal lesions have enjoyed immense popularity as a model of recovery from damage. In part, the popularity has been supported the laminar organization of the hippocampal formation, which allows for the dissection of the contribution of individual afferent pathways to the recovery process. The commissural/associational pathway is of particular interest, since electrophysiological and gross anatomical data, although limited, have correlated sprouting in this pathway with behavioral recovery. Unfortunately, information relating recovery to synaptic structure is lacking. Addressing this issue, two analyses were conducted. Initially, a quantitative review of the literature reporting behavioral recovery following this type of lesion was conducted using meta-analytic techniques. Using this detailed information across decades of research, multiple linear regression analysis was conducted to address whether the morphological correlates of recovery could predict behavioral recovery. This resulted in an equation relating morphology and recovery that stood up well to several diagnostic tests. Moreover, this model suggests that synapse structure (in particular, synapse size and curvature, as well as terminal compartmentalization and the density of multi-synaptic terminals) holds a greater potential to predict behavioral recovery than increases in synapse number, which is typically seen as the optimal anatomical measure of recovery. This initial attempt to identify, quantify, and validate a model of lesion recovery is an important initial step in understanding how synaptic morphology may help mediate recovery of function.     

Genetic approaches to the study of synaptic plasticity and memory storage

Long-term memory is believed to depend on long-lasting changes in the strength of synaptic transmission known as synaptic plasticity. Understanding the molecular mechanisms of long-term synaptic plasticity is one of the principle goals of neuroscience. Among the most powerful tools being brought to bear on this question are genetically modified mice with changes in the expression or biological activity of genes thought to contribute to these processes. This article reviews how strains of mice with alterations in the cyclic adenosine monophosphate/protein kinase A/cyclic adenosine monophosphate-response element-binding protein signaling pathway have advanced our understanding of the biological basis of learning and memory.     

Macro-contexts for learning: Initial findings and issues

The purpose of this paper is to explore the use of video-based technologies to create macro-contexts that can facilitate comprehension and learning. A theoretical rationale for the use of macro-contexts is considered, and the results of three experiments are described. The experiments involve very simple uses of technology yet show positive results. The results suggest that more sophisticated uses of technology, especially computer-controlled interactive videodiscs, should have even greater benefits on comprehension and learning. The findings provide a rationale for conducting more extensive investigations that utilize sophisticated technologies.     

FUNCTIONAL ANALYSIS OF A PROGRAM FOR TRAINING HIGH AND LOW PREFERENCE PEERS TO MODIFY DISRUPTIVE CLASSROOM BEHAVIOR1

Although considerable evidence has accumulated regarding the effectivenes of peers as behavior managers, little attention has been directed toward the analysis of components of training programs. Also, it is not known whether high and low preference peers have different reinforcing effects. In this study, a two-phase peer training program was introduced to five high preference and five low preference peer managers. The Managers were assigned one to each of 10 grade-four elementary pupils with high rates of disruptive behavior. Peer Training I was composed of instructions to monitor and reinforce target subject behavior on a time-sample schedule, to record this reinforcement, and to ignore inappropriate behavior in target subjects. Peer Training II introduced, in addition, backup reinforcement for the monitoring behavior of managers. Measures were taken of target subject behavior, antecedent and consequent attention from managers and other peers, monitoring behavior of managers, teacher behavior, and preference ratings of peer managers by target subjects. Significant improvements in target subject behavior occurred following Peer Training I and further improvements occurred following Peer Training II. These changes were paralleled by decreases in the frequency of antecedent and consequent manager attention to problem behaviors, and improvements in the number and accuracy of monitoring checks. Recorded reductions in teacher attention to individual children and to target subjects were not statistically significant. Posttest preference scores improved significantly over pretest scores for low preference managers, while remaining high for high preference managers.