Neural correlates of schema-dependent episodic memory and association with behavioral flexibility in autism spectrum disorders and typical development

Background Conceptual knowledge frameworks termed schemas facilitate memory formation and are posited to support flexible behavior. In adults, the medial temporal lobe (MTL) and medial prefrontal cortex (mPFC) trade-off in supporting schema-based memory formation, such that encoding of subsequently remembered schema-congruent information relies on mPFC, whereas schema-incongruent information relies on MTL. Whether this is true in the immature brain and relates to behavioral flexibility is unknown. In this preliminary investigation, we aimed to replicate the adult findings in typically developing (TD) children and to investigate the relevance to behavioral flexibility by examining a disorder with pathognomonic behavioral rigidity, autism spectrum disorder (ASD). Methods Children completed an associative subsequent memory paradigm, encoding object-scene pairs in an MRI scanner and subsequently completing a recognition test outside the scanner after a delay. Recognition performance was back sorted to construct remembered vs forgotten contrasts. One-way ANOVAS were conducted in MTL and mPFC masks for schema-congruency, followed by congruency by flexibility scores. Exploratory analyses were then conducted within the whole brain. Results As reported in adults, episodic memory was strongest for schema-congruent object-scene pairs, followed by intermediate pairs, and lowest for schema-incongruent pairs in both TD and ASD groups. However, the trade-off between mPFC and MTL in TD children differed from adult reports such that mPFC supported memory for intermediate schema-congruency and left anterior MTL supported memory for schema-congruent pairs. In ASD, mPFC engagement interacted with flexibility such that activation supporting memory for intermediate schema-congruency varied with parent-reported flexibility and was higher in those with more flexible behavior. A similar interaction was also observed in both the left dorsolateral and rostrolateral PFC in whole-brain analysis. Conclusion Our findings provide the first preliminary evidence for the association of schema-based episodic memory formation and behavioral flexibility, an executive function impaired in multiple developmental disorders. Upon replication, this line of research holds promise for memory-based interventions addressing executive problems of behavioral rigidity.

Introduction to the symposium. The concept of protean power: change we can believe in?

This introductory article to the symposium first presents and then critiques the protean power concept of the Katzenstein and Seybert volume. Although the volume underestimates the value of rational choice models to explain some cases of protean power, it rightly demonstrates that our conventional theoretical toolkit insufficiently anticipates many such disruptions. Drawing on the examples of post-World War I veterans' movements and India's 1998 decision to test nuclear weapons, I argue that the protean power research agenda should focus on the reciprocal relationship between radical uncertainty and psychological and behavioral rigidity.

Contrafreeloading in Rats Is Adaptive and Flexible: Support for an Animal Model of Compulsive Checking

Contrafreeloading involves working unnecessarily to obtain a reward that is otherwise freely available. It has been observed in numerous species and can be adaptive when it provides an organism with updated information about available resources. Humans frequently update their knowledge of the environment through checking behaviors. Compulsive checking occurs when such actions are performed with excessive frequency. In a putative animal model of compulsive checking, rats treated chronically with the dopamine agonist quinpirole display exaggerated contrafreeloading for water. Although this effect has been attributed to behavioral rigidity, some evidence suggests the behavior remains somewhat flexible and may be adaptive under certain conditions. We assessed the ability of quinpirole-treated rats with contrafreeloading experience to adapt to changing contingencies by requiring them to alternate between response levers. Rats treated with quinpirole or saline were first trained to obtain water by pressing either of two levers. Next, free water was made available for 8 days, and contrafreeloading was measured. Rates of contrafreeloading were significantly higher in the drug-treated rats than in controls. On the following 5 days, each reward caused the associated lever to become inactive until a reward was earned from the alternate lever. Quinpirole-treated rats learned this new response requirement more quickly than controls. Thus, exaggerated checking behavior induced by chronic quinpirole treatment can be advantageous when environmental contingencies change. These results provide support for this animal model of compulsive checking and hint at the presence of a specialized neural checking module involving the dopamine system.

Behavioral Rigidity between Traditional and Nontraditional College Students

The Test of Behavioral Rigidity was administered to a group of Traditional (age ≤ 22 years) and Nontraditional (age ≥ 25 years) college students to assess the significance of mean differences in rigidity scores between the groups. Analysis indicated significant differences between the groups on Personality-Perceptual Rigidity and the Composite Rigidity Quotient, with the Nontraditional students scoring as less rigid (more flexible). Within each group, women were significantly less rigid (more flexible) on Psychomotor Speed Rigidity and on the Composite Rigidity Quotient. Results argue against the belief that Nontraditional students find it difficult to adjust readily to new situations and tasks and that rigidity increases with age. Further, within both groups of students women scored as more flexible than men. Implications of these results for higher education are discussed.

Decision-Making in Old Age: Cautiousness and Rigidity

The purpose of the present study was to test the findings of Botwinick's work on cautiousness and decision-making in old age [1, 2], along with an examination of two factors not previously studied: rigidity and certainty of decision outcome. Sixty-four elderly participants of both sexes participated in filling out the Choice Dilemmas Questionnaire (CDQ) after having been classified as high or low on Schaie's Test of Behavioral Rigidity [3]. In general, Botwinick's conclusions were supported: 1. when given the opportunity to avoid making decisions on the CDQ, the elderly did so, even under conditions of no risk at all concerning the outcome of the decision; 2. elderly individuals appeared to become more conservative and cautious in their decisions when the outcome was directed at the lives of young individuals than when older individual's lifestyles were of concern. This latter phenomenon, however, was not seen when the elderly participant was required to make a decision and could not elect to abstain. In addition, rigidity was found to be related to risky decisions made by the elderly individual.

Correlates of Behavioral Rigidity

The present study investigated the correlations between measures of behavioral rigidity and aptitudes. Forty-two male institutionalized delinquents were tested on the Test of Behavioral Rigidity and the General Aptitude Test Battery. Significant but small correlations were found between most aptitudes and the Psychomotor and Composite scales of the Test of Behavioral Rigidity and suggest that greater rigidity appears to be related to lower aptitudes.