Behavioral, affective, and cognitive alterations induced by individual and combined environmental stressors in rats

Objective: To evaluate whether exposing rats to individual or combined environmental stressors triggers endophenotypes related to mood and anxiety disorders, and whether this effect depends on the nature of the behavior (i.e., innate or learned). Methods: We conducted a three-phase experimental protocol. In phase I (baseline), animals subjected to mixed schedule of reinforcement were trained to press a lever with a fixed interval of 1 minute and a limited hold of 3 seconds. On the last day of phase I, an open-field test was performed and the animals were divided into four experimental groups (n=8/group). In phase II (repeated stress), each group was exposed to either hot air blast (HAB), paradoxical sleep deprivation (PSD) or both (HAB+PSD group) on alternate days over a 10-day period. Control group animals were not exposed to stressors. In phase III (post-stress evaluation), behavior was analyzed on the first (short-term effects), third (mid-term effects), and fifth (long-term effects) days after repeated stress. Results: The PSD group presented operant hyperactivity, the HAB group presented spontaneous hypoactivity and anxiety, and the HAB+PSD group presented spontaneous hyperactivity, operant hypoactivity, impulsivity, loss of interest, and cognitive impairment. Conclusion: A combination of environmental stressors (HAB and PSD) may induce endophenotypes related to bipolar disorder.

Análise funcional do comportamento autolesivo / Functional analysis of self-injurious behaviors

OBJETIVO: Apresentar e analisar estudos que mostram como o comportamento autolesivo (SIB) relaciona-se funcionalmente com mudanças no ambiente, em geral dependentes do comportamento. Essa descrição tem sido chamada de análise funcional e torna possível, por meio de estratégias experimentais, determinar quais são as mudanças ambientais relevantes na manutenção do SIB. MÉTODO: Quarenta e seis artigos empíricos, publicados entre 1991 e 2010, foram encontrados na revisão feita nos seguintes bancos de dados: Science Citation Index Expanded, Social Sciences Citation Index e Arts & Humanities Citation Index. Foram analisados em mais detalhes 25 artigos aplicados que se baseiam em métodos empíricos de análise funcional e propõem tratamentos para SIB. Artigos teóricos, de revisão ou que discutiam criticamente o procedimento de análise funcional não foram incluídos na revisão. RESULTADOS: Entre as mudanças ambientais relevantes na manutenção do SIB, a literatura analisada mostra que o SIB pode depender de apresentação de atenção, evitação (ou fuga) de demandas, ou não depender de qualquer fonte externa de estimulação. Esses resultados esclarecem sobre os princípios comportamentais básicos envolvidos na manutenção do SIB: reforçamento positivo, reforçamento negativo ou reforçamento automático. CONCLUSÃO: É apontada a necessidade da análise funcional de SIB para tratamentos que visem reduzir esse comportamento. Por fim, defende-se que intervenções comportamentais podem ser inseridas em programas de saúde.

OBJECTIVE: To present and analyze studies that sought to describe how self-injurious behavior (SIB) is functionally related to environment changes. This description has been called functional analysis and makes it possible, by means of experimental strategies, to determine which environmental changes are relevant to the maintenance of SIB. METHOD: Forty-six empirical articles published between 1991 and 2010 were found in the review based on studies indexed in the Science Citation Index Expanded, Social Sciences Citation Index and Arts & Humanities Citation Index databases. We analyzed, in more detail, 25 applied articles that have used empirical methods of functional analysis and treatments for SIB. RESULTS: The literature reviewed shows that the SIB may depend on presentation of attention, avoidance (or escape) of demands, or do not depend on any external source of stimulation. These results shed new light on the basic behavioral principles that can contribute to the maintenance of SIB: positive reinforcement, negative reinforcement, or automatic reinforcement. DISCUSSION: It is pointed out the necessity of functional analysis of SIB to base treatments that reduce this behavior. Finally, we argue that behavioral interventions can be put into health programs.