Natividad Sánchez

Involvement of D1 and D2 dopamine receptor in the retrieval processes in latent inhibition

RationaleContemporary theories propose that latent inhibition (LI) is due to a process of interference with the context playing a key role as recovery cue. Physiological studies have demonstrated that LI is a process dependent on striatal dopamine. D2 dopamine receptors have been specifically associated with its expression, while D1 receptor has shown a limited function. However, to evaluate the role of dopamine receptors in LI, it is necessary to analyse their activity during recovery phase, where the mechanisms involved in interference processes are performed.ObjectiveThe experiments studied the involvement of the dopaminergic system in the retrieval process of LI. We analysed the effect of the systemic administration of dopaminergic D1 (SCH-23390) and D2 (sulpiride) antagonist during the test phase on LI and on its contextual specificity.MethodsAnimals were pre-exposed to saccharin solution and conditioned with a LiCl administration in conditioning phase. Dopaminergic antagonist drugs were administered during the test phase. Experiment 2 used the same context in all the phases. Experiment 3 used a new context during conditioning and test phase.ResultsThe D2 antagonist increased the LI effect and, in turn, diminished the normally suppressant effect of the context shift on LI. The opposite effect was observed under the D1 antagonist administration. This drug disrupted LI and enhanced the effect that the context shift had on this cognitive process.ConclusionsD2 receptor had a relevant role on retrieval processes of pre-exposure learning, while D1 receptor was related with the contextual control of conditioning.

Pavlov in America: A Heterodox Approach to the Study of his Influence

This work presents a critical analysis of Pavlovs influence that goes beyond the conventional view: that which reduces his influence in American psychology to the behaviorism of Watson and Hull. In order to understand the nature of the Russian physiologists influence in American psychology, we propose a distinction between three approaches to it: 1) the symbolic approach, on representing a model of the possibility of constructing an objective psychology; 2) the methodological approach, given the importance of the technique of conditional reflexes; and 3) the theoretical approach, which is derived from his theory of higher nervous activity. This perspective permits us to suggest that most of Pavlovs influence on behaviorism was of a symbolic and methodological nature--though the methodological influence also reached other authors that did not belong to the behaviorist traditions, as was the case of Mateer. As far as the theoretical influence is concerned, our work proposes that it is more visible in authors such as Gantt and Liddell, or even in authors such as Boldirev, Director of the Pavlovian Laboratory at the Battle Creek Sanitarium in Michigan. The case of Gantt is especially interesting because, in addition to his important contributions, he played an essential role in the foundation of the Pavlovian Society, and the journal Conditional Reflex. What our work proposes is that to understand the nature of Pavlovs influence in American psychology it is necessary to take into account the very characteristics of that psychology: its pragmatic interests, its methodological rigor, the dominant systems of neo-behavioral theory and the changes that occurred after the Second World War.

I. P. Pavlov, la actividad nerviosa superior y la psicología

ResumenEn el presente trabajo se realiza un analisis historico de la obra del reflexologo I. P. Pavlov en el que se persiguen tres objetivos fundamentales: el primero es tratar de describir el cambio de intereses que, durante los primeros anos del siglo XX, se produce en las investigaciones llevadas a cabo por Pavlov y sus colaboradores desde el estudio de los procesos digestivos al estudio de la actividad nerviosa superior. En segundo lugar, analizamos algunos de los aspectos fundamentales de la teoria pavloviana incidiendo en su alto grado de sistematizacion. Por ultimo, reflejamos el interes mostrado por Pavlov ante la psiquiatria, interes que se hace patente en sus opiniones y debates con algunos de los mas prestigiosos psiquiatras de su epoca. En este sentido se abordan las consideraciones que de las aportaciones realizadas por Janet, Freud y Schilder realiza Pavlov.